pathogenesis of breast cancer

1. genetic changes

1.1. over expression of HER2/NEU proto-oncogene or amplification of RAS & MYC gene

1.2. mutation of tumer suppressor gene RB & TP53

1.3. also, large number of genes including estrogen receptor gene maybe inactivated

1.4. gene expression can separate the breast cancer into 4 sub-types:

1.4.1. luminal A (estrogen receptor–positive, HER2/NEU-negative)

1.4.2. luminal B (estrogen receptor–positive, HER2/NEU overexpressing)

1.4.3. HER2/NEU positive (HER2/NEU over expressing, estrogen receptor–negative)

1.4.4. basal-like (estrogen receptor–negative and HER2/NEU-negative)

1.5. Roughly one third of women with hereditary breast cancer have mutations in BRCA1 (at chromosomal locus 17q21.3) or BRCA2 (located on chromosomal band 13q12-13)

2. hormonal influences

2.1. Endogenous estrogen excess, or more accurately, hormonal imbalance, clearly has a significant role. Many of the risk factors mentioned

3. environmental variable

3.1. Environmental influences are suggested by the variable incidence of breast cancer in genetically homogeneous groups and the geographic differences