Association of intron microsatellite status and exon mutational profiles of TP53 in human colorectal cancer

Microsatellite instability (MSI) and loss of heterozygosity (LOH), which cause genomic instability, contribute to cancer pathogenesis. However, only few studies have evaluated the association of a single microsatellite locus of the TP53 gene with the mutation spectra of TP53 exons. A total of 256 patients with colorectal cancer were enrolled in the present study. MSI/LOH alterations of a microsatellite in the TP53 intron (TP53ALU) were assessed via short tandem repeat scanning. The exon mutation profile was evaluated by direct sequencing. The mutation rate of TP53 exons was significantly higher in tumors with LOH alterations of TP53 introns compared with those in tumors with a microsatellite-stable status in the TP53 intron (P=0.0047). TNM stage II was significantly more frequent in MSI vs. LOH or MSS of the TP53 intron (P=0.027 and P=0.048, respectively). Thus, microsatellite alterations may be valuable predictors of TP53 exon mutation and the TNM stage of colorectal cancers.