Gamma-rays-induced death of human cells carrying mutations of BRCA1 or BRCA2

There is now evidence to suggest that BRCA1 and BRCA2 are involved in the r esponse of cells to DNA damage and cell cycle checkpoint control. This repo rt examines the death pathways of human cells with various BRCA1 and BRCA2 genotypes after exposure to gamma-rays, A lack of functional BRCA1 and BRCA 2 led to defective repair of DNA double-strand breaks in irradiated cells. This impairment resulted in a relaxation of cell cycle checkpoints, product ion of micronuclei, and a loss of proliferative capacity, Heterozygous BRCA 1 and BRCA2 mutations also led to enhanced radiosensitivity, with an impair ed proliferative capacity after irradiation. The existence of a phenotype r elated to radiosensitivity in BRCA1(+/-) and BRCA2(+/-) cells raises the qu estion of the response of heterozygous women to radiation.