Skip to content

03.Oncogenes

Regulators of Cell growth

  1. Proto-Oncogenes
  2. Tumor Suppressor Genes
  3. Regulators of Apotosis
  4. other factors

Tumor Suppressor Genes

  1. P53
    • mutation of Both P53 gene causes Cancer
    • One gene mutation Li-Farumani syndrome increase the risk of Cancers.
graph TD
    X[Cell from  G1-Phase to S-phase] ==>X1[P53 detects DNA damage];
    X1 ==> X1a[Upregulate DNA repair Enzymes] & X1b[Upregulate Pro-Apoptotic BAX]
    X1a ==> X1ab[DNA repair];
    X1b ==>X1bc[Blocks Bcl2];
    X1bc ==> X1bcd[Apoptosis];
  1. Retinoblastoma
    • E2F need for cell from G1 to S phase
    • Rb is bound to E2F
    • Cyclin D1/CDK4 phosphorylase's and releases E2f
    • Both gene mutation leads ,Abnormal Rb causes to Free E2F aling all cell to S-phase
    • Good Gemes from prerna
      • one gene mutated , one good gene = no disease
      • One gene mutation ,and other gene mutated on same cell *very rare *** = Unilateral Retinoblastoma
    • Father already had Bad gene , Good mother gene
      • mutation of good gene = Bilateral Retinoblastoma,osteosarcoma

Regulators of Apoptosis

  1. Bcl2 = prevent Cytochrome C from leaks
    • Follicular Lymphoma t(14;18)(heavy chain:BCL2 gene) = Over expression , prevention of Cytochrome C from Leakage ,no cell death if failed in antibody production/Auto-immunity.

Proto-Oncogenes

Categories of Proto-Oncogenes

  1. Growth Factor
  2. Growth Factoer Receptors
  3. Signal Transducers
  4. Transcription factors

  5. Cell cycle Regulators

  6. Cell growth and Differentiation

  7. Mutation of Proto-Oncogene = Uncontrolled Cell growth and Differentiation

Proto-Oncogenses

1.Growth Factors

Growth Factors Cancer
PDGF Astrocytoma - autocrine Loop

2.Growth Factor Receptors

Receptors Type of Cell growth factor bindong Carcinoma
ERBB2/HERs/neu erpidermal growth factor receptor subset of Breast cancer
RET Neural Growth Factor receptor Medullary Carcinoma,MEN2A,MEN2B
KIT stemcell GF receptor Gastrointestinal intestinal stroma

3.Signal Transducers

Transducer function mutation Carcinoma
RAS(most tumours) GTP binding protein GTPase enzyme point mutation melonam,lymphoma,carcinoma
ABL Tyrosine Kinase t(9:22) with BCR CML,types of AML

4.Nucelar Transcription Factors

Factors Mutation Carcinoma
C-myc t(8;14) Burkitt lymphoma
N-myc Nueroblastoma
L-myc Lung Cancer

5.Cell cycle Regualrtors

Regulator Mutaion CAncer
Cyclin-D1 t(11:14) Mantle cell lympoma
CDK4 Melanoma

Other Factors

  1. MHC-1 detecting Abnormal Protein and Killing

    • Down regulation MHC-1 expression
    • Immunodeficiency of other causes

  2. Telomere shortening

    • Telomerase enzyme

  3. Angiogenesis for Nutrients

    • FGF & VEGF