Pathogenesis of Cancer

• The pathogenesis of cancer involves a complex interplay of genetic, environmental, and lifestyle factors leading to the transformation of normal cells into malignant ones.
• Key mechanisms and processes of Pathogenesis of Cancer include:

1. Genetic Mutations

• Oncogenes: Mutations activate genes like RAS and MYC, causing uncontrolled cell proliferation.
• Tumor Suppressor Genes: Inactivation of genes like TP53 removes growth restraints.
• DNA Repair Genes: Mutations in genes such as BRCA1 and BRCA2 lead to genomic instability.

2. Environmental and Lifestyle Factors

• Carcinogens: Substances like tobacco smoke and asbestos cause mutations.
• Radiation: UV and ionizing radiation damage DNA.
• Infections: Viruses (e.g., HPV, HBV, HCV) and bacteria (e.g., Helicobacter pylori) contribute to cancer.
• Diet and Physical Activity: Poor diet, obesity, and lack of exercise increase cancer risk.

3. Epigenetic Changes

• DNA Methylation: Aberrant patterns can silence tumor suppressor genes or activate oncogenes.
• Histone Modification: Affects gene expression and contributes to carcinogenesis.
• Non-coding RNAs: Regulate gene expression and play roles in cancer development.

4. Tumor Microenvironment

• Cancer Stem Cells: Self-renewing cells drive tumorigenesis.
• Angiogenesis: New blood vessel formation supplies the tumor; VEGF is key.
• Immune Evasion: Tumors express proteins like PD-L1 to evade the immune system.

5. Progression and Metastasis

• Invasion: Cancer cells degrade the extracellular matrix using enzymes like MMPs.
• Metastasis: Spread of cancer cells to distant organs involves detachment, invasion, survival in circulation, and colonization of new sites.

6. Clonal Evolution

• Genetic Heterogeneity: Diverse cell populations within tumors drive clonal evolution and therapy resistance.

Thank you for reading from Firsthope's notes, don't forget to check YouTube videos!