Impact of codon 72 Arg > Pro single nucleotide polymorphism in TP53 gene in the risk of kangri cancer: a case control study in Kashmir.

Kangri cancer found only in Kashmir (north India) is a unique thermally induced squamous cell carcinoma of the skin that develops because of chronic and persistent irritation due to the use of a kangri (a brazier) by the Kashmiri people to combat the chilling cold temperature during winter. Being unique to this region, the molecular etiology of the invasive kangri cancer is not known fully. The TP53 gene, codon 72 polymorphism (Arg72Pro), has been found to be associated with cancer susceptibility but has not been investigated in kangri cancer risk. A case control study was conducted to find the genotype distribution of TP53 Arg72Pro SNP and to elucidate the possible role of this SNP as risk factor in kangri cancer development. Using the polymerase chain reaction-restriction fragment length polymorphism approach, we tested the genotype distribution of 106 kangri cancer patients in comparison with 200 cancer-free controls from the same geographical region. A significant difference was observed between the control and kangri cancer patients with odds ratio = 2.02 and 95% confidence interval = 1.2-3.3 (p = 0.01). Interestingly, the proline form was abundantly observed in advanced-grade tumors (p < 0.05). We also found a significant association of the variant allele (GC + CC) with male subjects and patients >45 years of age (p < 0.05). Thus, it is evident from our study that Arg72Pro SNP is implicated in kangri cancer and that the rare, proline-related allele is connected with higher susceptibility to kangri cancer.