According to the International Agency for Research on Cancer, 1 in 5 people will likely develop cancer in their lifetime.

Rising Global Cancer Burden: Inherited Risk and Future Projections

• In 2022, there were 20 million new cancer cases and nearly 10 million deaths due to cancer. By 2045, this is expected to increase to 32 million cases and 16 million deaths.
• Asia is predicted to have almost half of the world’s cancer cases by 2045.
• Inherited Cancer Risk:
  • About 10% of cancers are caused by genetic mutations passed down from parents.
  • These inherited mutations are more common in ovarian cancer (20%) and occur in about 10% of people with breast, colorectal, lung, and prostate cancers.

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Genome Editing

• Genome editing refers to technologies that allow scientists to change an organism’s DNA. 
  • This involves adding, removing, or altering genetic material at specific points in the genome.
• CRISPR-Cas9 Technology
  • CRISPR-Cas9 is a popular genome editing tool because it is faster, cheaper, more accurate, and more efficient than other methods.
  • It was adapted from a natural defence mechanism used by bacteria to fight viruses.
• How does CRISPR-Cas9 Works?
  • Bacteria store viral DNA segments in their genome, forming CRISPR arrays. 
    • These arrays help them recognize and cut the DNA of attacking viruses using the Cas9 enzyme.
  • Scientists have adapted this process to target and edit specific DNA sequences in human cells using guide RNA and the Cas9 enzyme.
• Applications in Disease Treatment
• • Genome editing is helpful to treat diseases like cystic fibrosis, haemophilia, and sickle cell disease.
  • It also holds promise for more complex conditions, such as cancer, heart disease, and HIV.

Ethical Concerns

• Most genome editing affects somatic cells (non-reproductive cells), meaning changes aren’t passed to future generations.
• Editing germline cells (egg or sperm) raises ethical concerns since these changes could be inherited.
  • Currently, germline editing is illegal in many countries due to safety and ethical issues, especially regarding enhancing human traits like intelligence or height.

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About Hereditary Cancer Syndromes

• Hereditary cancer syndromes are genetic disorders where mutations in one or more inherited genes increase the risk of developing cancer. 
  • These mutations can also cause cancer to develop at an earlier age.
• Key Features
  • Individuals with hereditary cancer syndromes have a higher lifetime risk of cancer. 
  • They may also develop multiple independent cancers in their lifetime.
• Causes
  • Most of these syndromes are caused by mutations in tumor suppressor genes, which normally protect cells from becoming cancerous. 
    • Other affected genes include those responsible for DNA repair, oncogenes (genes that promote cancer growth), and angiogenesis (the formation of blood vessels).
• Common Syndromes
  • Examples include Hereditary Breast-Ovarian Cancer Syndrome and Lynch Syndrome (Hereditary Non-Polyposis Colon Cancer).

BRCA Genes

• The BRCA1 and BRCA2 genes, discovered in the mid-1990s.
• These are important for understanding hereditary cancer, particularly breast and ovarian cancers.
• BRCA and Cancer Risks
  • Mutations in the BRCA1 and BRCA2 genes increase the risk of breast, ovarian, and fallopian tube cancers in women, as well as prostate and breast cancer in men.
  • These mutations are also linked to a higher risk of cancers like pancreatic, colorectal, and uterine cancers.
• Prevalence of BRCA Mutations
  • BRCA mutations occur in about 1 in 400 people. 
  • However, certain groups, like Ashkenazi Jews, have a much higher prevalence of 1 in 40 individuals.

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Importance of Genetic Testing and Treatment

• Genetic Testing for BRCA Mutations
  • Testing for BRCA mutations is important as it helps identify people at higher risk for cancer. 
    • This allows for personalised prevention strategies, such as regular screening or preventive surgeries.
• Targeted Therapies for BRCA Mutations
  • Treatments like PARP inhibitors have shown promise in treating cancers caused by BRCA mutations.