Oncology Today | BRCA1 gene

What happens when BRCA1 gene is mutated? 
The diagram below depicts the beginning of mutation.

BRCA1 mutation

What do the statistics show?
Among all the women suffering from breast cancer, almost one third of them have had a close relative, or a first-degree relative with breast cancer.Take the recent example of actor.Angelina Jolie.
Around 4 to 9% people are considered to have hereditary breast cancer.
Hence, individuals who have had first-degree relatives diagnosed with breast cancer, are very likely to be diagnosed with the same.
Preventive Mastectomy is all over the news now, and there are many discussions about whether or not women should opt for it, if they have found out a genetic trait that puts them to a great risk.The responsible genes are BRCA1 and BRCA2 gene.

What are BRCA1 and BRCA2 genes?

• two genes associated with familial breast cancer and also ovarian cancer
• high prevalence seen  in families with breast cancer or ovarian cancer or both.
• in a research, it was found that women whohad breast cancer diagnosed before 35 years of age, BRCA1 mutations were detected in 6.2% of them
• majority of BRCA1 mutations are detected in individuals with moderate- to high-risk families.
• individuals who show BRCA1 or BRCA2 mutations, the lifetime risk of developing breast cancer ranges from 40 to 80% .

 What are the BRCA1-related breast cancers characteristics?

• earlier age at onset,
• lower diploidy rate,
• higher proliferative rate, 
• higher mitotic counts,
• higher proportion of progesterone receptor-negative tumors,
• and more lymphocytic infiltration than sporadic cancers(not related to mutation of this gene)

 What are the BRCA2-related cancer characteristics?

•  cancers had lower mitotic counts,
•  higher score for tubule formation, 
• and greater proportion of continuous pushing margins than sporadic tumors.

 BRCA1 associated cancers usually have poor prognosis, or lesser chance of survival
 but this chance is similar to or better than sporadic tumors of similar stage.

Heriditory or familial breast cancer, however, accounts for less than 10% of all existing breast cancers,
and BRCA1- and BRCA2-related heriditory breast cancers maybe responsible for only two-thirds to
three-quarters of these cases.
Other genetic abnormalities and less common syndromes like Li-Fraumeni, etc are responsible for some small number of breast cancers.
This type of cancer can be prevented , if the genetically predisposed individuals are spotted.

Also read
What are the 12 causes of cancer?
What is metastasis?
What are benign tumors?
What is malignancy?
30 common terminologies in Oncology.