Pathophysiology_of_Lung_Cancer power point presentation

Pathophysiology of lung cancer

1. Pathophysiology of Lung Cancer In-depth Explanation

2. Cellular Origin • Lung cancer originates from epithelial cells lining the airways or alveoli. • Most lung cancers (90%-95%) arise from the bronchial epithelium. • Rare cases arise from glandular or neuroendocrine cells.

3. Genetic and Molecular Changes (1) 1. Mutations in Oncogenes: - EGFR mutations: Promote unchecked cell proliferation. - KRAS mutations: Common in smokers. - ALK rearrangements: Found in adenocarcinomas. - Other mutations: ROS1, MET, RET. 2. Inactivation of Tumor Suppressor Genes: - TP53 mutations: Loss of tumor suppression. - RB1 inactivation: Common in SCLC.

4. Genetic and Molecular Changes (2) 3. Epigenetic Alterations: - Methylation of CpG islands in tumor suppressor genes. 4. Angiogenesis Activation: - VEGF promotes new blood vessel formation. - Facilitates tumor growth and survival.

5. Initiation and Progression • Initiation: - Exposure to carcinogens (e.g., tobacco smoke, radon, asbestos). - Induces DNA damage and mutations. • Progression: - Accumulation of genetic and epigenetic changes. - Leads to clonal expansion of malignant cells.

6. Tumor Microenvironment • Cancer-Associated Fibroblasts (CAFs): - Promote tumor growth and resistance to therapy. • Immune Evasion: - Tumor cells express immune checkpoint proteins (e.g., PD-L1). - Suppresses T-cell activity.

7. Spread and Metastasis • Local Spread: - Invades pleura, chest wall, diaphragm. • Lymphatic Spread: - Regional lymph nodes (hilar, mediastinal). • Hematogenous Spread: - Common sites: Brain, liver, bones, adrenal glands.

8. Paraneoplastic Syndromes • SIADH: Hyponatremia due to ectopic ADH secretion (SCLC). • Hypercalcemia: Ectopic PTHrP secretion (NSCLC). • Cushing Syndrome: Ectopic ACTH secretion.

9. Immune Dysregulation • Tumor cells manipulate the immune system to evade detection. • Express immune checkpoint inhibitors (e.g., PD-1/PD-L1). • Suppresses anti-tumor immune responses.