BReast Cancer Associated proteins 1 and 2 (BRCA1, -2) and Partner and Localizer of BRCA2 (PALB2) protein are tumour suppressors linked to a spectrum of malignancies, including breast cancer and Fanconi anemia.
We also find that 18 VOUS BRCA1 and BRCA2 variants that are listed in BRCA Exchange are present at least once in the homozygous state in patients who lack features of Fanconi anemia.
A previously reported molecular interaction between BRCA1 and the FA protein, FANCD2, supports the hypothesis that both breast-cancer-susceptibility genes are components of the FA pathway, functioning in DNA-damage response.
We showed that BRCA1 mediates the recruitment of FANCD2 by gammaH2AX to damaged chromatin and cells deficient or depleted of H2AX exhibit an FA-like phenotype, including an excess of chromatid-type chromosomal aberrations and hypersensitivity to MMC.
Taken together, our results show that loss of Brca1 in murine BM causes hematopoietic defects similar to those seen in people with FA, which provides strong evidence that Brca1 is critical for normal hematopoiesis and that Brca1 is a bona fide FA-like gene.
RAD6B is a major mediator of triple negative breast cancer cisplatin resistance: Regulation of translesion synthesis/Fanconi anemia crosstalk and BRCA1 independence.
FANCD2, a downstream component of the FA pathway, has recently been shown to be ubiquitinated in response to DNA damage and to translocate to nuclear foci containing BRCA1, a breast cancer susceptibility gene product, suggesting a role for this protein in DNA repair functions.
Our data expand the clinical spectrum associated with biallelic BRCA1 mutations, ranging from embryonic lethality to a mild FA-like phenotype and no chromosome fragility.
Genes mutated in patients with Fanconi anemia (FA) interact with the DNA repair genes BRCA1 and BRCA2/FANCD1 to suppress tumorigenesis, but the molecular functions ascribed to them cannot fully explain all of their cellular roles.
Because brip1 mutant cells are proficient for ubiquitination of FANCD2 protein, our data indicate that BRIP1 has a function in the Fanconi anemia pathway that is independent of BRCA1 and downstream of FANCD2 activation.
Crosslinking agents and ionizing radiation induce damage in cancer cells that requires the FA/BRCA pathway to be resolved; thus cancers that are deficient in BRCA1, BRCA2, or any other component of the FA/BRCA pathway are hypersensitive to these agents.
Epigenetic silencing of essential components of DNA repair pathways is a common event in many tumor types, and comprise O6-methylguanine-DNA methyltransferase (MGMT), human mut L homolog 1 (hMLH1), Werner syndrome gene (WRN), breast cancer susceptibility gene 1 (BRCA1), and genes of the Fanconi anemia pathway.
The link between BRCA1 dysfunction and basal-like breast cancer or triple-negative breast cancer (TNBC) has been suggested; however, the associations of other factors involved in the Fanconi anemia (FA)/BRCA pathway with the pathogenesis of basal-like breast cancer remain unidentified.
Here, we report the presence of biallelic BRCA1 mutations in a woman with multiple congenital anomalies consistent with a Fanconi anemia-like disorder and breast cancer at age 23.
Taken together, our results show that loss of Brca1 in murine BM causes hematopoietic defects similar to those seen in people with FA, which provides strong evidence that Brca1 is critical for normal hematopoiesis and that Brca1 is a bona fide FA-like gene.