Understanding the role of a Genetic Counselor in HBOC:
Hereditary Breast and Ovarian Cancer (HBOC) syndrome is a cancer pre-disposition syndrome which indicates high risk of breast and ovarian cancer in adults. It is to be noted that only 5-10% breast or ovarian cancers are hereditary in nature, others are sporadic or non-hereditary. HBOC is an inherited genetic condition, in which the disease is passed from one generation to another in a family. There are 2 primary genes associated with HBOC syndrome: BRCA1 and BRCA2 but there are other genes contributing to breast/ovarian cancer like TP53, PTEN, CDH1, ATM, CHEK2, PALB2 etc. Mutation (or defect) in BRCA1 or BRCA2 genes increases the risk of breast/ovarian cancer in women whereas men have high risk of developing breast/prostate cancer. HBOC also poses a slight risk of developing other cancers such as pancreatic cancer and melanoma.
Prevalence of HBOC in India: According to a research study, screening of over 1000 Indian patients with breast and/or ovarian cancer employing a multi-gene panel indicated that there is a high prevalence of mutations in the high-risk breast cancer genes: BRCA1, BRCA2, TP53, and PALB2.
Inheritance Pattern for HBOC: There are more than 20,000 genes in human body and each gene is normally present in 2 copies. In general, one copy is inherited from the mother and the other is inherited from the father. HBOC follows autosomal dominant inheritance pattern, i.e. the mutation (defect) in single copy of a gene is sufficient to increase the risk of cancer. For example, if one parent has gene mutation, then their children will have 50% chance of inheriting the mutation/disease.
BRCA1 & BRCA2 Genetic Testing: Testing negative for BRCA1 and BRCA2 does not eliminate the possibility of developing HBOC since the other genes contributing can be responsible for cancer.
Risk Prevention & Treatment Options: National Comprehensive Cancer Network (NCCN) guidelines suggest that women with a BRCA1/2 pathogenic variant could consider mastectomy as a primary surgical treatment for breast cancer. Treatment of ovarian and other cancers in individuals with a BRCA1/2 pathogenic variant is similar to that for sporadic cancers. Prophylactic bilateral mastectomy, prophylactic oophorectomy, and chemoprevention are also advised for women.
Annual Checks & Self-assessment: Breast self-examination, annual clinical breast examination, annual mammography, and MRI for breast cancer assessment. Annual trans-vaginal ultrasound and CA-125 concentration might be considered for ovarian cancer screening. Annual prostate cancer screening is recommended in case of males.
Role of a Genetic Counselor in HBOC Management: Genetic counselors help patients to understand and treat the condition by discussing necessary course of actions. They also give relevant information about people related to patients who could be at risk, providing both pre-test and post-test counseling.
Ms. Jeanny Dominic, B.Tech – Genetic Engineering and PG Diploma in Genetic Counseling , Kamineni Hospital, Hyderabad, India.
February 19, 2020
1. Singh J, Thota N, Singh S, Padhi S, Mohan P, Deshwal S, Sur S, Ghosh M, Agarwal A, Sarin R, Ahmed R. Screening of over 1000 Indian patients with breast and/or ovarian cancer with a multi-gene panel: prevalence of BRCA1/2 and non-BRCA mutations. Breast cancer research and treatment. 2018 Jul 1;170(1):189-96.
2. Saxena S, Szabo CI, Chopin S, Barjhoux L, Sinilnikova O, Lenoir G, Goldgar DE, Bhatanager D. BRCA1 and BRCA2 in Indian breast cancer patients. Human mutation. 2002 Dec;20(6):473-4.
Dr. Nida Rehmani, Ph.D
Scientific Editor at Bio-Services,