RESUMEN
<p><b>OBJECTIVE</b>To study the possible etiological role of MLH1 gene 415G/C polymorphism in sporadic Chinese colorectal cancer (CRC) patients.</p><p><b>METHODS</b>Ninety-seven sporadic CRC patients and 138 normal controls were collected from Hubei Provincial Cancer Hospital and the People's Hospital of Wuhan University. In addition, five CRC families including 6 patients and their 19 first-degree relatives were also recruited. Genomic DNA was extracted from peripheral blood samples. Gene mutation was analyzed by PCR-RFLP. MLH1 mRNA expression in colorectal mucosa was analyzed by RT-PCR.</p><p><b>RESULTS</b>The frequency of MLH1 gene CC genotype was significantly higher in sporadic CRC patients than that in controls (P=0.035, OR=5.29, 95% CI: 1.07-26.04). In the CRC families, the C allele frequency of CRC patients and their relatives was increased, compared with sporadic CRC patients and normal controls, respectively (P=0.003 and P=0.006). MLH1 mRNA expression of colorectal mucosa was similar in different genotypes.</p><p><b>CONCLUSION</b>MLH1 gene 415G/C polymorphism might be a risk factor to sporadic CRC in Chinese. The mutation does not affect the MLH1 mRNA expression. For first-degree relatives from CRC families, carriers of MLH1 415C allele have a high risk to CRC.</p>