There are various tumor suppressor genes present in the cell which regulates the activity of the oncogene. As the activity of the tumor suppressor gene reduces or the activity of oncogene increases, the result may be the development of cancer. BRCA gene mutation is the example of reduction in the activity of tumor suppressor gene leading to increased risk of breast and ovarian cancer.
Can BRCA Skip a Generation?
BRCA gene does not skip generation. It is the autosomal dominant gene in which only a single copy of the gene is enough to increase the risk of breast cancer. The chances for transferring the mutated gene to the next generation are 50:50 and the risk increased to 50-80% for the development of breast cancer due to such mutation. In males the mutation of BRCA may lead to breast cancer and prostate cancer.
Various genetic mutation leads to various diseases. The increase in risk of the disease depends upon the activity that the mutated gene performs. The mutation in DNA mismatch repair genes increases the chances of cancer. Both BRCA1 and BRCA2 genes are non-related to each other but are responsible for the prevention of cancer in breast and other tissues. Both these genes work through repairing the faulty DNA to prevent cancer and if the DNA cannot be repaired, both genes express cell death.
They work downstream to the level of chromosome repair and if due to any reason, the BRCA gets mutated, the person has the increased chances of breast cancer. Thus, they are generally performing the function of tumor suppression. The BRCA gene test is done to identify the presence of mutation in BRCA1 and BRCA2 through DNA analysis.
The hereditary factor including the mutation in these gene accounts for approximately 8-10% of the breast cancer. Not all the people with BRCA mutation show the symptoms of cancer. It has been estimated that only about 10% of the people know that they have genetic mutation while the other 90% are living without any knowledge. The chances of this mutation are low, and it is estimated to be 1 in 400. With the mutation in BRCA gene the risk of breast cancer is 50-80% while the risk of ovarian cancer due to this mutation is 30-45%. As this mutation does not confirm the presence of cancer and only increases the risk, proper care and periodic examination is vital for early diagnosis of the cancer.
Symptoms Of Breast Cancer
Breast cancer is the condition in which the cells of the breast continuously divide resulting in the formation of lump in the breast. The formation of lump is generally regarded as the first sign of tumor. Apart for the lump, the other symptoms include blood from the nipples, and change in shape of the breast. The patient may also experience discharge from nipples, and swollen lymph nodes.
Genetic Relationship Of BRCA
Mutation in BRCA gene is autosomal dominant which indicates that only one copy of the faulty gene is sufficient to increase the risk of developing breast and ovarian cancer. In male, mutation in BRCA may cause breast cancer but the risk is high for developing prostate cancer. Almost 1-2% of the patient of prostate cancer is found to have BRCA mutation. As the genetic mutation is autosomal dominant thus the chances of transferring it to the next generation is 50:50. The mutated BRCA gene does not skip generation. Once the mutation is found in any of the family members, the other closely related members such as brother, sister or children should be genetically screened to diagnose the presence of BRCA gene mutation in them. In male, the chances of breast cancer due to mutation in BRCA gene are about 2-5%. If a patient suffering from breast cancer is found to have a negative BRCA test, the chances are that the cancer has been developed due to mutation in a gene other than BRCA. It is to be noted that the genetic mutation of BRCA itself does not cause cancer rather it increases the chances of developing cancer. Thus, the hereditary transfer is not of cancer rather it is increased risk which is transferred.