An indirect measure of cancer susceptibility to radiation in Iranian breast cancer patients with different ethnicity

BACKGROUND: Breast cancer is the leading cancer among Iranian women. Iran has citizens from diverse ethnic groups. Candidate genes for increased breast cancer risk are those involved in DNA damage repair pathways, and mutations in these genes are characterized by increased chromosomal radiosensitivity. To investigate the in vitro chromosomal radiosensitivity of patients with breast cancer and the possible influence of ethnicity and clinical parameters on it, the micronucleus assay was used in the present and absent of bleomycin as a radiomimetic agent.METHODS: Chromosomal radiosensitivity was analysed with the micronucleus assay using lymphocytes of breast cancer patients and healthy individuals of different ethnic groups. DNA damages expressed as micronuclei are scored specifically in once-divided binucleated cells arrested at cytokinesis in this technique. The micronucleus is an established biomarker for genomic instability indicating chromosome breakage and/or whole chromosome loss. Lymphocytes were treated with defined doses of bleomycin, and micronuclei (MN) were scored in 1000 binucleated cells in each sample. These MN frequencies were correlated with the ethnicity and clinical parameters of the breast cancer patients.RESULTS: MN values were higher in breast cancer patients than in healthy controls in all ethnicity groups. The lower MN frequency was observed in triple negative (ER-, PR-, HER2-) breast cancer groups that indicate the radioresistance in this group. CONCLUSION: Iranian breast cancer patients have elevated chromosomal radiosensitivity compared with healthy controls. Triple negatives also influences chromosomal radioresistance. Our results indicated that genomic instability consideration that expressed as MN in blood could be used as personal risk assessment and radiotherapy response prediction in breast cancer.

کلیدواژه ها:

genomic instability ، Micronucleus assay ، Breast cancer ، Radisensitivity