MLH1 and malignant colon neoplasm: These 3 SNPs include rs1800734 located 93 base pairs upstream of the MLH1 start site, and rs749072 and rs13098279 which are located further downstream of MLH1. We have also shown through in vitro studies in transformed colon cancer cell lines that the allelic variant of rs1800734 decreases MLH1 promoter CpG island-mediated transcriptional activity, thereby providing insight into its potential role as a functional SNP [12].