Alternative names: breast cancer gene, identification of the 5382insC mutation.
Breast cancer remains the most common form of malignant neoplasm in women, with an incidence of 1 case in every 9-13 women aged 13-90 years. You should know that breast cancer also occurs in men - approximately 1% of all patients with this pathology are men.
The study of tumor markers, such as HER2, CA27-29, allows us to identify the disease at an early stage. However, there are research methods that can be used to determine the likelihood of developing breast cancer in a particular person and his children. A similar method is a genetic study of the breast cancer gene - BRCA1, during which mutations of this gene are identified.
Material for research: blood from a vein or scraping of the buccal epithelium (from the inner surface of the cheek).
Why do you need genetic testing for breast cancer?
The goal of genetic research is to identify people at high risk of developing genetically determined (predetermined) cancer. This provides an opportunity to make efforts to reduce risk. Normal BRCA genes provide the synthesis of proteins responsible for protecting DNA from spontaneous mutations that contribute to the degeneration of cells into cancer.
Patients with defective BRCA genes should be protected from exposure to mutagenic factors - ionizing radiation, chemical agents, etc. This will significantly reduce the risk of the disease.
Genetic testing can identify familial cases of cancer. Forms of ovarian and breast cancer associated with BRCA gene mutations have a high degree of malignancy - they are prone to rapid growth and early metastasis.
Analysis results
Typically, when studying the BRCA1 gene, it is checked for the presence of 7 mutations at once, each of which has its own name: 185delAG, 4153delA, 3819delGTAAA, 2080delA, 3875delGTCT, 5382insC. There are no fundamental differences in these mutations - they all lead to disruption of the protein encoded by this gene, which leads to disruption of its functioning and an increase in the likelihood of malignant degeneration of cells.
The result of the analysis is displayed in the form of a table, which lists all variants of the mutation, and for each of them the letter designation of the type is indicated:
- N/N – no mutation;
- N/Del or N/INS – heterozygous mutation;
- Del/Del (Ins/Ins) – homozygous mutation.
Interpretation of results
The presence of a BRCA gene mutation indicates a significant increase in a person's risk of developing breast cancer, as well as some other types of cancer - ovarian cancer, brain tumors, malignant tumors of the prostate and pancreas.
The mutation occurs in only 1% of people, but its presence increases the risk of breast cancer - in the presence of a homozygous mutation, the risk of cancer is 80%, that is, out of 100 patients with a positive result, 80 will develop cancer during their lifetime. With age, the risk of cancer increases.
The detection of mutant genes in parents indicates their possible transmission to offspring, so children born to parents with a positive test result are also recommended to undergo genetic testing.
Additional Information
The absence of mutations in the BRCA1 gene does not guarantee that a person will never develop breast cancer or ovarian cancer, since there are other reasons for the development of cancer. In addition to this analysis, it is recommended to examine the status of the BRCA2 gene, located on a completely different chromosome.
A positive result for mutations, in turn, does not indicate a 100% likelihood of developing cancer. However, the presence of mutations should cause the patient to be on increased alert for cancer - it is recommended to increase the frequency of preventive consultations with doctors, monitor the condition of the mammary glands more closely, and regularly undergo tests for biochemical markers of cancer.
With the most minor symptoms indicating the possible development of cancer, patients with identified BRCA1 gene mutations should urgently undergo an in-depth examination for oncology, including the study of biochemical tumor markers, mammography, and, for men, .
Literature:
- Litvinov S.S., Garkavtseva R.F., Amosenko F.A. and others. Genetic markers for assessing the risk of developing breast cancer. // Abstracts of the XII Russian Oncological Congress. Moscow. November 18-20, 2008. P.159.
- J. Balmaña et al., ESMO Clinical Guidelines for Diagnosis, Treatment and Follow-up of BRCA-positive Breast Cancer, 2010.
Referring to the latest advances in genetics, visitors are asked to determine whether you are at risk for arthritis, hypertension, diabetes, heart attack, stroke... The list of diseases that potential clients are ready to predict includes cancer.
Those who wish can also carry out full sequencing (that is, determine the sequences of all genes) in order to predict life many years in advance using the genome map. Moreover, the client does not even have to go to the clinic. The courier himself will bring a testing kit to your home, which collects a little saliva, and then in your personal account on the same website, in about a week you will be able to find out the result. True, such pleasure costs 10 thousand dollars. As you can see, the service is not for the poor. And the RG correspondent decided to find out how much of this can be believed.
Where is cancer hiding?
Finding out in advance whether there is a risk of developing cancer seems very tempting - many types of cancer can be successfully treated in the early stages. In addition, scientists have actually already found many genes, mutations in which lead to the development of certain types of cancer.
There are already more than 900 different genetic tests, but the reliability of their results often remains questionable, explains oncologist, head of the NETONCOLOGY.RU project Sergei Gordeev. - Their widespread use can do more harm than good. Yes, in some cases, the tendency to develop a certain type of cancer can be inherited, but this does not mean the disease itself is inevitable.
For example, genetic analysis for predisposition to breast cancer. Even among those women in whom the dangerous gene for breast cancer is found, only 8 out of 10 will actually develop breast cancer by age 65. But they certainly should be aware of this risk. If it is, you need to be regularly examined by a mammologist. Although, unfortunately, those who do not have an inherited gene are not immune from breast cancer. In addition to such breakdowns in genes, spontaneous mutations can also occur under the influence of a variety of reasons, and there are also other risk factors. The picture is approximately the same with other genetic tests for predisposition to cancer and other serious diseases.
Nets without a catch
Is it even possible to identify all predispositions to all types of cancer, of which, let me remind you, there are more than 200? After all, to do this, you need to check all the genes that can in one way or another affect the development of the disease!
In such cases, they study gene polymorphism (that is, their variants found in different people. - Author), and here the situation is even worse,” explains Alexander Karpukhin, head of the laboratory of molecular genetics of complexly inherited diseases of the Medical Genetics Center of the Russian Academy of Medical Sciences, Doctor of Biological Sciences. -Even if there are some changes in genes, the risk of developing cancer is not much higher than the population average. And to say that only a change in lifestyle or something like that will help is profanation, leading away from serious issues.
Nevertheless, there are already several tests that actually help to detect certain types of cancer in the early stages. Some are even included in medical examination programs. An example is a test for prostate cancer markers (PSA - prostate-specific antigens), which all men over 45 years old should undergo.
Tests of this kind must have two important properties - sensitivity and specificity, says Professor Alexander Karpukhin. - That is, to “catch” all suspicious signs of trouble in the prostate and precisely those that are characteristic of cancer. The sensitivity of this test is fine, but the specificity is low: an increase in the level of these antigens is associated with cancer in only 25% of cases, and in the rest with other diseases. Therefore, even a positive result of such a test is not a reason to panic. Only a biopsy, when a piece of tissue is taken for laboratory analysis, can clarify the diagnosis. And so far there are literally only a few at least partially reliable cancer markers.
Non-transferable DNA portrait
Well, how can a complete genetic portrait - genome sequencing - help us?
Today, only a few can afford to order the full sequence of their genes. Thus, some celebrities, such as the great geneticists James Watson or Craig Venter, have already deciphered their genome. They say that genetic self-portraits are ordered by billionaires and Hollywood actors - for the future, you never know... The prospects for this portrait, some scientists say, are boundless. In the future, it will be able to identify our predisposition to certain diseases, our creative and other abilities, and will make it possible to influence life expectancy and self-realization. Others are scary: this information can be used against you by your employer or insurance company, criminals and swindlers of all stripes. What is it really like?
I’m afraid that at the current level of science, all the data obtained are very relative and have significance only as statistical material,” says Evgeniy Platonov, chief researcher at the Institute of General Genetics of the Russian Academy of Sciences, Doctor of Biological Sciences. - Yes, some mutations in the genome will pop up, for example, you will find out that at the end of your life you will develop Alzheimer's disease... But so far medicine cannot treat it, and you will have to pay money in advance.
Full genome sequencing is not yet ready for widespread practical use, believes Professor Alexander Karpukhin. - In most cases, it is possible to understand which genes an inherited disease is associated with based on family history and then specifically investigate them. But in cases where this is not clear, sequencing the entire genome is not enough. It is also necessary to prove that the disease is associated precisely with the changes found, that is, to conduct an in-depth study. And this is another level.
It seems that the tempting promises of Internet sites to predict everything about your health for the rest of your life are so far nothing more than a pseudoscientific deception.
Apparently, the promisers themselves understand this. Thus, the site, which until recently promised to predict all risks of cancer, has today moderated its appetites. And it offers only specific programs: “Cancer in women” - 7 types and “Cancer in men” - 5 types. Both for 9945 rubles. But as already said, this only makes sense in cases of familial hereditary types of cancer.
The same site offers a complete genetic study of a person for 24,495 rubles, and genome sequencing - generally for 299,990 rubles. And also with an incomprehensible practical result.
But still, is it possible to predict the development of cancer in time, at the earliest stage? Modern medicine answers: yes, and with a high degree of probability. If you have had cases of cancer in your family, and more than one, you really need to see a doctor, who in most cases will be able to determine the very fact of inheriting the disease and the degree of risk.
Many large medical centers here and abroad today offer special check-up programs, that is, a complete health examination using the most modern diagnostic equipment. In some cases, they also help identify early signs of cancer. True, they also cost a lot of money - from one and a half to two thousand dollars. But the results are completely practical.
As for cancer prevention, here, alas, all the advice seems banal: quit smoking, don’t abuse alcohol, watch your weight, eat right, exercise... Bored? But over all millennia, humanity has not yet come up with anything smarter and more effective. Although we have learned to sequence the genome.
– a heterogeneous group of malignant tumors of various organs, caused by the inheritance of one or more genes that cause a particular form of cancer or increase the likelihood of its development. Diagnosed based on family history, genetic tests, symptoms and additional research data. Treatment tactics are determined by the type and extent of neoplasia. The most important role is given to the prevention of the development of neoplasms, which includes regular examinations of the patient, exclusion of risk factors, treatment of precancerous diseases and removal of target organs.
General information
Hereditary forms of cancer are a group of malignant neoplasms caused by mutations of one or more genes and transmitted by inheritance. They make up about 7% of the total number of cancers. The likelihood of a tumor occurring varies significantly depending on the specific genetic mutation and the living conditions of the carriers of the gene. There are so-called “cancer families” in which up to 40% of blood relatives suffer from malignant neoplasia.
The current level of development of genetic research makes it possible to reliably establish the presence of defective genes in family members at risk of hereditary forms of cancer. In this regard, modern scientists and practitioners are increasingly focusing on preventive measures aimed at preventing diseases of this group. Diagnosis and treatment of hereditary forms of cancer are carried out by geneticists, specialists in the field of oncology, gastroenterology, pulmonology, endocrinology and other fields of medicine.
Causes of hereditary forms of cancer
Modern research reliably confirms the version about the genetic nature of cancer. It has been established that the cause of the development of all forms of cancer is DNA mutations, which result in the formation of a clone of cells capable of uncontrolled reproduction. Despite the genetically determined nature of malignant tumors, not all neoplasias are hereditary forms of cancer. Typically, the occurrence of neoplasia is caused by non-inherited somatic mutations caused by ionizing radiation, contact with carcinogens, certain viral infections, decreased immunity and other factors.
Truly hereditary forms of cancer are less common than sporadic ones. At the same time, the risk of developing malignant neoplasia is extremely rarely 100% - genetic disorders that necessarily cause cancer are found in only 1 person out of 10 thousand of the population, in other cases we are talking about a more or less pronounced predisposition to the occurrence of certain oncological lesions. About 18% of healthy people have two or more relatives suffering from cancer, but some of these cases are caused by coincidences and the influence of unfavorable external factors, and not by hereditary forms of cancer.
Experts were able to identify signs of a hereditary tumor phenotype:
- Young age of patients at the time of onset of symptoms of the disease
- Tendency to multiple lesions of various organs
- Bilateral neoplasia of paired organs
- Inheritance of cancer in accordance with Mendel's laws.
It should be taken into account that in patients with hereditary forms of cancer, not all of the above symptoms may be detected. However, the identification of such parameters allows us to differentiate hereditary tumors from sporadic tumors with sufficient confidence. Taking into account the nature of the inherited trait, the following options for the transmission of genetic abnormalities are distinguished:
- Inheritance of a gene that provokes the development of a certain cancer
- Inheritance of a gene that increases the likelihood of developing a certain cancer lesion
- Inheritance of several genes that cause cancer or increase the risk of cancer.
The mechanisms of development of hereditary forms of cancer have not yet been fully established. Scientists suggest that the most likely are an increase in the number of cellular mutations, a decrease in the efficiency of eliminating mutations at the cellular level, and a decrease in the efficiency of eliminating pathologically altered cells at the body level. The reason for the increase in the number of cellular mutations is a hereditarily determined decrease in the level of protection from external mutagens or a dysfunction of a certain organ, causing increased cell proliferation.
The reason for the decrease in the effectiveness of eliminating mutations at the cellular level in hereditary forms of cancer may be the absence or lack of activity of certain enzymes (for example, in xeroderma pigmentosum). Decreased elimination of altered cells at the body level may be caused by hereditary immune disorders or secondary suppression of the immune system due to familial metabolic disorders.
Hereditary forms of cancer of the female reproductive system
There are several syndromes characterized by a high risk of developing cancer of the female reproductive system. In three syndromes, tumors of one organ are transmitted: ovarian cancer, uterine cancer and breast cancer. In other hereditary forms of cancer, a predisposition to the development of neoplasia of various localizations is revealed. There are familial ovarian and breast cancer; familial ovarian, uterine and breast cancer; familial cancer of the ovaries, uterus, breast, gastrointestinal tract and lungs; familial cancer of the uterus and gastrointestinal tract.
All of these hereditary forms of cancer can be caused by various genetic abnormalities. The most common genetic defects are mutations in the tumor suppressor genes BRCA1 and BRCA2. These mutations are present in 80-90% of patients with hereditary ovarian and breast cancer. At the same time, in some syndromes, these mutations are detected in only 80-45% of patients, which indicates the presence of other, still unstudied genes that provoke the development of hereditary forms of cancer of the female reproductive system.
Patients with hereditary syndromes are characterized by certain features, in particular, early onset of menarche, frequent inflammatory and dysplastic processes (mastopathy, endometriosis, inflammatory diseases of the female genital organs), and a high prevalence of diabetes mellitus. The diagnosis is made based on family history and molecular genetic studies.
If a predisposition to hereditary forms of cancer is identified, an extensive examination is carried out, it is recommended to give up bad habits, a special diet is prescribed, and the hormonal profile is corrected. Upon reaching the age of 35-45 years, according to indications, a bilateral mastectomy or oophorectomy is performed prophylactically. The treatment plan for mature tumors is drawn up in accordance with the general recommendations for neoplasia of the corresponding localization. Hereditary neoplasms of this group proceed quite favorably; the five-year survival rate for such forms of cancer is 2-4 times higher than for sporadic cases of the disease.
Hereditary forms of cancer of the digestive system
There is a large group of hereditary syndromes with a high probability of developing gastrointestinal tumors. The most common is Lynch syndrome - non-polyposis colon cancer, transmitted in an autosomal dominant manner. Along with colon carcinoma, patients with Lynch syndrome may have ureteral cancer, small intestinal cancer, stomach cancer and uterine cancer. The disease can be caused by terminal mutations of various genes, most often MLH1, MSH2 and MSH6. The likelihood of developing Lynch syndrome with abnormalities of these genes ranges from 60 to 80%.
Since patients with this hereditary form of cancer make up only about 3% of the total number of patients with colon cancer, genetic screening tests are considered inappropriate and are carried out only when a predisposition is identified. Healthy patients are advised to regularly undergo extensive examination, including colonoscopy, gastroscopy, abdominal ultrasound and pelvic ultrasound (in women). When a tumor appears, it is recommended to carry out not segmental resection, but subtotal colectomy.
The second most common hereditary form of gastrointestinal cancer is familial adenomatosis of the colon (FACA), also transmitted in an autosomal dominant manner. The disease is caused by a mutation in the APC gene. There are three types of SATC: weakened (less than 100 polyps), classic (from 100 to 5000 polyps), severe (more than 5000 polyps). The risk of malignant transformation in the absence of treatment is 100%. Patients with this hereditary form of cancer may also have adenomas of the small intestine, duodenum and stomach, central nervous system tumors, soft tissue neoplasms, multiple osteofibromas and osteomas. All patients undergo an annual colonoscopy. If there is a threat of malignancy, patients with severe and classic hereditary forms of cancer undergo colproctectomy. With a weakened type of SATC, endoscopic polypectomy is possible.
The group of hamartomatous polyposis syndromes includes juvenile polyposis, Peutz-Jeghers syndrome, and Cowden disease. These hereditary forms of cancer are manifested by polyposis of the stomach, small and large intestine. Often combined with skin lesions. Colorectal cancer, tumors of the stomach and small intestine may occur. Regular endoscopic examinations of the gastrointestinal tract are indicated. If there is a threat of malignant degeneration, endoscopic polypectomy is performed.
Hereditary forms of stomach cancer are divided into two types: diffuse and intestinal. Diffuse neoplasms develop with their own hereditary syndrome caused by a mutation of the CDH1 gene. Intestinal tumors are detected in other syndromes, including mutations causing malignant neoplasia of the ovaries and breast, as well as Lynch syndrome. The risk of developing cancer with a mutation in the CDH1 gene is approximately 60%. Patients are recommended to undergo prophylactic gastrectomy). Familial forms of the disease are detected quite rarely. Nephroblastoma is often combined with developmental anomalies of the genitourinary system. Manifested by pain and gross hematuria. Treatment – nephrectomy, radiation therapy, chemotherapy. There are descriptions of successful organ-saving operations in the literature, but such interventions have not yet been introduced into widespread clinical practice.
Li-Fraumeni syndrome is a hereditary form of cancer that is transmitted in an autosomal dominant manner. Manifested by the early occurrence of sarcomas, breast cancer, acute leukemia, neoplasia of the adrenal glands and the central nervous system. Neoplasms are usually diagnosed before the age of 30 and have a high tendency to recur. Regular preventive examinations are indicated. Due to the high risk of other tumors, treatment tactics for existing neoplasia may differ from the generally accepted ones.
Not so long ago, when cancer was diagnosed, patients simply gave up, because it was quite difficult to hope for some kind of positive outcome. But now the treatment of such ailments has become possible. Most neoplasms can be easily cured, but only if detect cancer in time and begin taking action immediately.
Analysis for predisposition to oncology is a faithful ally in health matters. Many countries introduce such a procedure as mandatory.
There are many tools that can detect the disease at a very early stage. During this period, the disease state does not yet manifest itself in symptoms.
There are genes that protect us from cancer, which are inherited from close relatives. However, we do not always receive only positive elements. When twenty or more genes are disrupted, vulnerability to tumor development may increase.
Despite the fact that not everyone talks about this topic in their families, it is necessary to find out for sure whether there were people in your family with cancer. This information will help you decide on a prevention or treatment strategy in the future.
To know exactly about the possible risks, it is necessary to do a test for genetic predisposition to cancer.
By taking a cancer predisposition test, you can, if necessary, set yourself up for a healthier lifestyle and introduce proper nutrition and all the elements that accompany health into it.
The risks associated with the appearance of oncological diseases can be calculated thanks to twenty-two genes, which have their own specific focus. You can check your predisposition to cancer by doing an appropriate test.
Principle of genetic testing
The information contained in human genes helps to detect susceptibility to cancer. In identifying risks, not only the history of diseases of the genus, but also a medical examination: genetic blood test for cancer becomes the best help in determining the complete picture.
A DNA test for diseases remains relevant throughout life, from birth to death. It can be returned to and applied to any appropriate situation. Therefore, it is important, if necessary, to contact specialists and conduct this research.
The history of family illnesses, embedded in DNA, helps determine the degree of likelihood of the disease occurring and identify the predisposition itself. This information becomes fundamental in treatment and prevention.
Knowing your predisposition to cancer in advance means being ready to strike back at the disease. It is thanks to an objective assessment of what is happening that you can build a treatment strategy and, with minimal effort, money and time, cope with the disease at a time when the likelihood of treatment being effective is greatest.
Another significant point in this diagnosis is psychological side. It is quite difficult to maintain inner peace and not worry if you suspect you have cancer. For some, it will be enough to undergo the study once and forever let go of fears and stories associated with genus diseases.
Consulting is divided into several important elements:
- Gathering information about the patient's history.
- Analysis of genetic information.
- Finding tools to reduce risks.
- Psychological consultation.
- Further measures.
If the result of the test for genetic predisposition is negative, this does not mean that visiting medical institutions is no longer necessary. There is always a possibility of neoplasms, so it is very important not to forget about prevention and examinations by a doctor, which are recommended to be carried out systematically.
How to check the mammary gland?
The forecasts in this area are quite disappointing. A large percentage of women are faced with this form of cancer. Only timely detection of the disease and competent therapy provides an almost one hundred percent guarantee of healing.
Every woman must undergo a breast cancer test in the form of an ultrasound examination annually.
After a woman passes the thirty-five year mark, it is recommended to undergo a mammogram, which is also sufficient to do once a year. This procedure is an x-ray of the mammary glands, performed without any pain.
Risk group
- Women should be more careful in this matter if the onset of menstruation occurred in a very early period of life (up to twelve years).
- Those representatives of the fair half of humanity who, having crossed the thirty-year mark, have not given birth, should also take their health seriously.
- This group includes women who have relatives who have experienced this disease.
- Those who have already been diagnosed with breast disease should also be checked periodically.
If you have enlarged lymph nodes in the armpit area, lumps are palpable, some strange changes occur in the skin, and there is also discharge from the nipples, you should immediately consult a doctor and undergo the necessary examination.
"Equipment for fast and accurate analysis"Prostate
Perhaps the most common ailment among the male half, which has crossed forty-five years of age. To feel calm and confident, you just need to undergo it every two years. You will also need a couple of tests for tumor markers of prostate cancer.
These studies reflect the situation quite accurately. It should be borne in mind that before the analysis it is not advisable to eat and the prostate gland should be in a calm state, that is, after other similar studies you must wait at least seven days. In case of prostate adenoma, as well as prostatitis, an annual test to detect cancer is necessary.
Colon
Another major cancer threat is colorectal cancer. The best way to check this area for tumors is through which the colon is examined for pathologies. The process can also take some tissue directly from the intestines for analysis, as well as remove small polyps.
This procedure is recommended for those over fifty every five years. In situations where the pathology was detected in close relatives, colonoscopy should be done starting from the age of forty. It is necessary to carefully monitor any changes in bowel function. Colorectal cancer can cause bleeding, constipation, and diarrhea. If these symptoms are present, you should consult a specialist.
Skin cancer
Melanoma is a fairly serious health threat. Considering current trends, the pursuit of a tan and the popularization of solariums, it is imperative to check the health of your skin. Even a simple examination by a doctor may be enough to detect the disease.
A change in the shade of the skin, as well as the structure of the elements that are on it (moles and age spots, lumps and ulcers) is a signal to think about the state of the body.
Cervical cancer
Unfortunately, not everyone goes to the doctor on time, so the situation often becomes irreparable. This pathology can develop regardless of the woman’s age. Heredity also doesn't matter.
It can be detected during a routine examination by a gynecologist. To respond in a timely manner, simply undergo routine inspections. Diagnosis of this zone is carried out absolutely painlessly. Just one procedure per year is enough from the moment a woman begins to be sexually active.
Diagnosis includes a meeting with a gynecologist, as well as. The last part of the diagnosis is performed in parallel with the doctor’s examination. A woman needs to be wary of various pathologies that are harbingers of cancer.
No matter how confident you are in your health, should not be neglected prevention and regular examinations at the frequency recommended by doctors. The price of carelessness is too high - your health.
[42-019 ] Predisposition to colorectal cancer
2590 rub.
Order
A genetic test that reveals a common hereditary predisposition to colorectal cancer and precancerous adenomatous polyps of the colon. It consists of studying the genetic marker LOC727677 (Location:8q24.21), which is associated with an increased risk of developing colorectal cancer.
What biomaterial can be used for research?
Buccal (buccal) epithelium, venous blood.
How to properly prepare for research?
No preparation required.
General information about the study
Colorectal cancer (cancer of the colon and rectum) is one of the most common cancers in the world. About 10% of the population has a genetic predisposition to it. First of all, the risk group includes people who have had cancer in their family.
Symptoms of colorectal cancer are numerous and nonspecific. It often develops from previously formed adenomatous polyps. Timely detection and removal of colon polyps can prevent the development of cancer and is characterized by a favorable prognosis, which is why regular examination is so important. Diagnostic instrumental studies use irrigoscopy or colonoscopy with biopsy to confirm tumor tissue. Treatment for colorectal cancer depends on its location, size and extent of spread, as well as the patient's age and health. Surgery is a common treatment for colorectal cancer.
The genetic study consists of analyzing the status of the genetic marker LOC727677 G(g.41686854)T, which characterizes the risk of colorectal cancer. The analysis reveals a general predisposition and is not associated with the diagnosis of rare forms of early familial colorectal cancer associated with genes MSH2 And MLH1(hereditary nonpolyposis colon cancer, Lynch syndrome). Locus LOC727677 (8q24) is a region that directly interacts with the gene MYC, which often plays a leading role in the development of malignant neoplasms due to dysregulation of the synthesis of proto-oncogenes (they encode proteins involved in the control of cell growth, division and differentiation).
The inner surface of the colon comes into contact with a large number of factors that can lead to cell damage. Therefore, the cells lining the intestinal wall are constantly renewed. A mutation that affects a gene that controls cell growth can cause cells to divide uncontrollably, usually causing a precancerous tumor (adenomatous polyp). If not treated promptly, it can eventually develop into cancer.
When a genetic risk is identified in the absence of pathology, the main method of prevention is long-term clinical observation, timely treatment of all precancerous conditions and elimination of factors that increase the risk of cancer.
Factors contributing to the development of colorectal cancer:
- dietary habits (high content of meat and foods rich in animal fats in the diet, and low content of plant foods);
- excessive alcohol consumption;
- smoking;
- age over 55 years;
- sedentary lifestyle;
- heredity (the possibility of hereditary transmission of the disease is evidenced by the presence of familial polyposis syndromes; there is an approximately 3-fold increase in the risk of developing colorectal cancer among first-degree relatives of patients with cancer or colon polyps);
- inflammatory bowel diseases (nonspecific ulcerative colitis, Crohn's disease, pancolitis with a disease duration of more than 10 years);
- history of colon adenoma;
- diffuse familial polyposis, single and multiple polyps, villous tumors;
- a history of cancer of the internal genital organs or breast in women;
- familial cancer syndromes;
- immunodeficiency states;
- work in hazardous work (high incidence of colorectal cancer among workers in asbestos production).
When is the study scheduled?
- With a family history of the disease (close relatives have diagnosed colorectal cancer or adenomatous polyposis).
- For primary tumors localized both within the colon and in other organs (breast, uterus, prostate).
What do the results mean?
LOC727677 G(g.41686854)T
|
G/ G |
G/ T |
T/ T |
Clinically significant genotypes associated with increased risk of colorectal cancer: G/ G, G/ T. In patients with such genotype variants, the risk is increased by 1.5-2 times compared to the general population.
Important Notes
The absence of a mutation in the studied genetic marker does not exclude colorectal cancer due to other causes, including hereditary cancer syndromes.
Genetic markers
- LOC727677 (LOC727677). Detection of mutation G(g.41686854)T (regulatory region of the gene)
- Cytological examination of material obtained during endoscopy (FGDS, bronchoscopy, laryngoscopy, cystoscopy, sigmoidoscopy, colonoscopy)
- Histological examination of surgical material