The diagnostic potential of glutathione S-transferase (GST) polymorphisms in patients with colorectal cancer.

BACKGROUND: Colorectal cancer (CRC) is one of the most common cancers in the world. Despite improvements in screening for early diagnosis, CRC is one of the leading causes of cancer deaths.

OBJECTIVES: The aim of the study was to determine a potential association between the frequency of GSTM1 and GSTT1 null genotypes and the risk of CRC in the Polish population. Moreover, we analyzed the clinical parameters with the glutathione S-transferase (GST) gene polymorphisms in patients with CRC.

MATERIAL AND METHODS: The study was conducted on 512 Caucasians, including 279 patients (105 women and 174 men) with CRC. DNA from peripheral blood was extracted and the multiplex polymerase chain reaction (PCR) technique was used for glutathione S-transferase theta (GSTT1) and mu (GSTM1) gene deletion genotyping.

RESULTS: We found no statistically significant differences in the frequency of the GST gene polymorphisms in patients with CRC and controls. The prevalence of the GSTM1*0 variant in the test subjects was higher than in controls (45.9% vs 42.9%; p > 0.05). The frequency of the GSTT1*0 variant was also higher in patients with CRC compared to the control population (21.1% vs 18.9%; p > 0.05). In addition, the effect of the GSTM1 and GSTT1 polymorphisms on the incidence of CRC was also analyzed. There was a slight, but not statistically significant, increase of the risk of colon cancer for the GSTM1*0 and GSTT1*0 variants. Moreover, we examined the GST genotype due to the cancer TNM classification and the location of the primary tumor. Statistically significant differences in the distribution of the GSTT1*0 and GSTT1*1 genotypes in both the stage and the location of the primary tumor were observed.

CONCLUSIONS: It is suggested that the GSTT1 polymorphism may have an impact on the severity of the tumor and its location.