Hereditary cancer

Source: This post on Hereditary cancer has been created based on the article “Genome editing is bringing clarity to the study of hereditary cancers” published in The Hindu on 8^th October 2024.

Why in news?

Recently, the International Agency for Research on Cancer estimates that one in five people worldwide has a lifetime risk of developing cancer, based on data covering 36 types of cancer across 185 countries.

About hereditary cancer

1. Definition: Hereditary cancers are those caused by inherited genetic mutations passed from parent to child. These mutations increase an individual’s predisposition to developing certain types of cancer.

Inheritance Pattern: Hereditary cancer syndromes are most often inherited in an autosomal dominant manner, meaning that an individual only needs one copy of the mutated gene from either parent to have an increased risk of cancer.

2. Prevalence: Around 10% of all cancer cases are believed to result from inherited mutations. The prevalence is higher for certain cancers, such as ovarian (20%) and breast, colorectal, lung, and prostate cancers (10%).

3. Genetic Syndromes: Over 50 genetic syndromes are known to predispose individuals to cancer. These syndromes are collections of specific symptoms caused by inherited genetic variants.

4. BRCA Genes: Mutations in BRCA1 and BRCA2 are linked to a higher risk of breast and ovarian cancers. In men, BRCA mutations increase the risk of prostate and male breast cancer. They can also lead to other cancers like pancreatic, colorectal, and uterine cancers.

5. Founder Effects: Certain populations, like Ashkenazi Jews, have a higher prevalence of specific BRCA mutations due to genetic bottlenecks and founder effects, where small gene pools lead to a higher frequency of certain mutations.

6. Screening and Prevention: Genetic testing for BRCA and other relevant mutations helps identify individuals at higher risk. This allows for preventive strategies, such as increased surveillance, lifestyle changes, preventive surgeries, or targeted therapies.

7. Targeted Therapies: Therapies such as PARP inhibitors are specifically designed for cancers with BRCA mutations, as they disrupt DNA repair mechanisms that these cancers rely on. New therapies continue to emerge based on further genetic research.

8. Role of CRISPR Technology: CRISPR screens allow researchers to create specific mutations in genes like BRCA to study their effects on DNA repair and cancer progression. These tools also help identify resistance to therapies.

9. Saturation Genome Editing: This technique enables detailed analysis of genetic variants within specific genes, as seen in recent studies on the RAD51C gene. Such research expands the understanding of cancer risk and informs the development of new treatments.

10. Early Detection and Public Health: Population prevalence studies highlight hereditary cancer risks within specific communities. Regular genetic screening can aid in early detection, leading to timely intervention and more effective treatment.

UPSC Syllabus: Science and technology