Table 3 Carriers of mutations affecting pathways mediated by BRCA1/2 in humans have low levels of spontaneous chromatid aberrations, micronuclei and spontaneous SCEs.
From: Evidence That BRCA1- or BRCA2-Associated Cancers Are Not Inevitable
Reference | System | Spontaneous chromatid exchanges, breaks or aberrations | Spontaneous SCEs as measured by BrdU MMC versus spontaneous |
|---|---|---|---|
Fanconi anemia patient whole blood T-lymphocyte cultures | 54% of homozygous Fanconi anemia patients do not have chromosome breakage | Â | |
Fanconi anemia lymphocytes and fibroblasts | Normal | Fivefold increase in the presence of an alkylating agent; fibroblasts were more sensitive than lymphocytes | |
BRCA1breast cancer families | 5 of 9 BRCA 1 mutation carriers had 0 spontaneous chromosome aberrations, including 2/3 carriers in the same family; carriers with aberrations had them in only 2% of cells | Â | |
Peripheral blood lymphocytes from breast cancer patients with BRCA1 or BRCA2 mutation | No significant differences in mean spontaneous chromatid breaks or mean spontaneous micronuclei were observed among BRCA1/2 patients, relatives and controls | Â | |
Human BRCA1-associated breast cancer | No increase in numerical chromosomal instability compared with sporadic tumors | Â | |
Human wild-type versus human homozygous BCA2/FA-D1 and FA-A B lymphoblastoid cell lines and primary fibroblasts | Two Fanconi lymphoblastoid cell lines have only ~1–2 × the number of spontaneous chromatid breaks as wild-type; a third had over 5× normal; FA-A fibroblasts show about 2× greater spontaneous chromatid aberrations; BRCA2/FA-D1 fibroblasts have 4.6 and 7.5× more | Vast majority of MMC-treated cells die but SCE numbers in surviving cells are ~1–2× spontaneous |