Inherent Radiation Sensitivity of Lymphocytes of Triple Negative (TN) and Luminal A: A Comparison Between Patients with Breast Cancer and Normal Individuals as Assayed by the Micronucleus Test

Background: About ۸۳% of patients with breast cancer (BC) undergoradiation therapy. These patients show various degrees of mild to acute reactionsduring and after the completion of treatment.The aim of this study was to compareinherent radiosensitivity of gamma-irradiated G۰-lymphocytes between BCpatients and normal individuals using cytokinesis blocked micronucleous assay.Methods: Three to ۴ mL blood was drawn in heparinized syringes frompatients and normal individuals. A portion of the sample was irradiated withgamma rays at a dose of ۳۰۰ cGy. Irradiated and non-irradiated samples werecultured in complete RPMI-۱۶۴۰ culture medium. A standard cytokinesis-blockedmicronucleus assay protocol was followed for the preparation of binucleatelymphocytes. Slides were prepared and stained in Giemsa. Thousand binucleatecells were scored for the presence of micronucleus (MN). Data were statisticallyanalyzed using SPSS software. Results: The results showed that the background frequency of micronuclei inboth groups of control and Luminal A (LA) patients was nearly similar andrelatively low but was significantly higher in triple negative BC (TNBC) patientsSignificantly different (P<۰.۰۱). The irradiation of lymphocytes led to a highfrequency of MN in control and LA patients, relatively higher in LA patients(P<۰.۰۰۱); but the frequency of MN was considerably lower in TNBC patientsafter irradiation.Conclusions: The results indicated radio-sensitivity of LA patients but radioresistancein TNBC patients. This different reaction of lymphocytes of patientswith BC might be due to different status of genome instability in these patients.

Keywords:

TNBC , luminal A , lymphocytes , micronucleus , breast canoer , inherent Radio-Sensitivity