Lack of Association of Intron 3 16 bp Polymorphism of TP53 with Breast Cancer among Iranian-Azeri Patients

Background: p53 gene is a well-known tumor suppressor gene that has several polymorphisms in both itsexons and introns. It has been suggested that intron 3 16 bp duplication polymorphism may affect the genefunction resulting in reduction or suppression of p53 anti tumor activity. In most case control studies a duplicatedallele has been noticeably more frequent in cases rather than controls but there are also conflicting results. Theaim of this study was to assess the association of intron 3 16 bp duplication polymorphism of p53 with breastcancer risk among Iranian-Azeri population. We also analyzed the clinicopathological information of patientsas an epidemiological description of breast cancer in the north-west of Iran. Materials and
Methods: This casecontrolstudy was performed on 221 breast cancer patients and 170 controls. Genomic DNA was extracted fromperipheral blood samples and tumor tissues. p53 PIN3 genotype was determined using electrophoresis of PCRproducts on 8% non-denaturing polyacrylamide gels and silver staining.
Results: In the control and case groups,respectively, 62.9% and 61.1% had no 16 bp insertion (A1A1 genotype), 7.1% and 7.7% had insertion in bothp53 alleles (A2A2) and 30% and 31.2% were heterozygous (A1A2). There was no significant difference betweengenotype frequencies as well as allelic frequencies in two case and control groups.
Conclusions: According tothe result of the present study, the intron 3 16 bp duplication polymorphism of p53 could not be assessed as amarker of risk factor for predisposition to breast cancer in Azeri population. However, a high frequency of A2allele (22.1%) in our population suggested that intron 3 16 bp duplication polymorphism may be a valuablemarker for study in other cancers with well designed large groups.