No significant association between 40bp ins/del promoter polymorphism of MDM2 and breast cancer susceptibility in Pakistani women

Abstract

Breast cancer remains the most prevalent malignancy among women, and is the second leading cause of mortality worldwide. Genetic heterogeneity in the MDM2 promoter region has been associated with increased cancer susceptibility. The study was designed to assess the impact of a 40-bp deletion/insertion mutation of the MDM2 gene (at position 1518, which has a putative TATA pattern) in both breast cancer patients and healthy participants. A total of 200 female participants were included in the present study, comprising 100 histologically confirmed breast cancer patients and 100 age- and sex-matched healthy controls. Patient samples were obtained from Bolan Medical Complex (BMC) and the Center for Nuclear Medicine and Radiotherapy (CENAR), Quetta, Pakistan. Along with blood sample collection, information regarding demographic, reproductive, and clinical characteristics was recorded. Genotyping of the MDM2 gene 40-bp insertion/deletion (ins/del) polymorphism was carried out using specific forward and reverse oligonucleotide primers. The genotype frequencies of the MDM2 polymorphism among breast cancer patients were 57% for ins/ins, 36% for ins/del, and 7% for del/del, whereas in the control group they were 59%, 35%, and 6%, respectively. The calculated odds ratio for the deletion allele was 1.208, with a 95% CI ranging from 0.383 to 3.812 (p = 0.939). No statistically significant associations were observed between breast cancer and menopausal status, age at menopause, parity, number of children, use of oral contraceptives, or history of breastfeeding (p > 0.05). These results suggest that the 40-bp ins/del polymorphism in the promoter region of the MDM2 gene is not significantly associated with the development of breast cancer in the studied population