Oncology: Genetics, Tumor Markers & Associations
Genetics
Tumor Suppressor Genes
- Retinoblastoma (Rb): Cell Cycle Regulation
- p53: Induces Cell Cycle Arrest & Apoptosis
- APC: Cell Cycle Regulation
- DCC: Cell Adhesion
- BCL: Apoptosis
- BRCA: DNA Repair
- Associated with BReast CAncer & Ovarian Cancer
- BRCA 1 – Increased Breast Cancer & Ovarian Cancer
- BRCA 2 – Increased Breast Cancer & Ovarian Cancer, Also Associated with Pancreas, Melanoma & Prostate
Proto-Oncogenes
- RAS: G Protein
- K-RAS – Associated with Pancreatic & Colorectal Cancer
- SRC: Tyrosine & Kinase
- c-KIT: Tyrosine Kinase – Seen in GIST
- SIS: PDGF
- ERB B: EGF
- MYC: Transcription Factors (c-myc, n-myc & l-myc)
- RET
Tumor Markers
General Tumor Markers Mn
- CEA: Colorectal & Gastric
- Also Elevated in Stomach, Thyroid, Breast, Ovary, Pancreas and Lung
- Can Be Falsely Elevated in Smokers
- AFP: Liver (Most Specific Tumor Marker)
- Also Elevated in Yolk Sac Ovary Tumors
- CA 19-9: Pancreas & Biliary
- NSE: SCLC & Neuroblastoma
- Chromogranin A: Carcinoid
- Calcitonin: Medullary Thyroid Cancer
- β-HCG: Testicular & Choriocarcinoma
- PSA: Prostate
- Most Sensitive Tumor Marker
- LDH: Metastatic Melanoma
- AFP: Yolk Sac
- HCG: Germ Cell
- Inhibin: Epithelial & Sex Cord Stromal
- CA 125: Epithelial Type Only, Ovarian Cancer
Associations & Risks
Infectious Association
- HPV: Cervical CA
- Inactivates p53
- H. pylori: Gastric CA
- HBV & HCV: HCC
- EBV: Nasopharyngeal CA & Burkitt’s Lymphoma
- HIV: Lymphoma
Carcinogens
- Coal: Larynx, Bronchus & Skin
- Benzene: Leukemia
- Asbestos: Lung CA #1 & Mesothelioma
UV Radiation
- Mechanism: Damages DNA & Repair Mechanisms
- Responsible for Chronic Damage: UV-B
- Best Protecting Factor: High Melanin
Mnemonics
Tumor Markers
- C-C: CEA Colorectal
- P-P: PSA Prostate
- Br-Br: BRCA Breast
- CA 19-9: 9 Laid on Left Side Looks Like a Pancreas
- CA 125: 25 Look Like Uterus with Ovaries Hanging Off
- AFP: Fetal Feeds Fetus – Yolk Sac in Gyn