Background: Various studies all around the world depicted the relationship of polymorphisms in tumor suppressor genes with risk of various cancers, but there are unambiguous conclusions on this association. A hospital based case-control study was designed to review the association of polymorphism of tumor suppressor genes p21 and p53 with breast cancer risk in women residing in rural Maharashtra.
Methods: Two single nucleotide polymorphisms (SNPs) a C>A transversion (Ser>Arg) at codon 31 of exon 2 (rs1801270), C>T transition occurring 20bp upstream from stop codon of exon 3 (rs1059234) in p21 gene and G>C (Arg>Pro) transition at codon 72 of exon 4 (rs1042522), G>T (Arg>Ser) transition at codon 249 in exon 7 (rs28934571) in p53 gene were studied. To precise the quantitative assessment, we enrolled 800 subjects sorted into 400 clinically confirmed breast cancer patients and 400 healthy women from a tertiary care hospital (Krishna Hospital and Medical Research Centre) of south-western Maharashtra. The genetic polymorphisms in p21 and p53 genes was studied by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method using blood genomic DNA isolated from breast cancer patients and controls. The level of association of polymorphisms was assessed using Odds ratio (OR) with 95% confidence interval and p-value identified using logistic regression model.
Results: After the analysis of SNPs (rs1801270, rs1059234) of p21 and (rs1042522, rs28934571) in p53 gene our analysis suggested that heterozygote Ser/Arg genotype with OR=0.66; 95% CI: 0.47- 0.91; p=0.0003 and homozygote variant Arg/Arg genotype with OR=0.23; 95% CI: 0.13- 0.40; p<0.0001of rs1801270 of p21 was negatively associated with risk of breast cancer in studied population.
Conclusion: The findings from this study supported that rs1801270 SNP of p21 was inversely associated with breast cancer risk in the studied rural women population.
Keywords: Genetic polymorphism; PCR-RFLP; breast cancer; p21; p53.