Promoter methylation and Ile105val polymorphism of GSTP1 gene in the modulation of colorectal cancer risk in ethnic Kashmiri population

Association of glutathione thioltransferase P1 (GSTP1) gene polymorphism with sensitivity to oxaliplatin and traditional Chinese medicine syndrome types in colon cancer patients

BACKGROUND

Colon cancer has a high incidence, and chemotherapy is still the only treatment for it. Oxaliplatin, as a third generation platinum chemotherapy drug, has a good efficacy in the treatment of colorectal cancer. However, due to the influence of genetic susceptibility, people with different genotypes have different sensitivities to oxaliplatin. As a result, the therapeutic effect varies greatly among different patients.

AIM

To explore the association of glutathione sulfhydryl transferase P1 (GSTP1) gene polymorphism with sensitivity to oxaliplatin and traditional Chinese medicine (TCM) syndrome types in colon cancer patients.

METHODS

A total of 246 colon cancer patients who received chemotherapy with oxaliplatin-based regimens at our hospital from January 2015 to June 2020 were selected. The Ile105Val polymorphism of GSTP1 gene was detected before chemotherapy, and the curative effect was evaluated after three cycles of chemotherapy. The clinical data and the distribution of GSTP1 genotypes of patients with different chemotherapy effects were compared, and the factors affecting the efficacy of oxaliplatin chemotherapy were analyzed. The distribution of TCM syndrome types of colon cancer patients was also calculated, and the relationship between GSTP1 genotype and TCM syndrome types and syndrome elements was evaluated.

RESULTS

There was a polymorphism in the Ile105Val locus of the GSTP1 gene, which conformed to the Hardy-Weinberg equilibrium law and was representative of the population (P > 0.05). After three cycles of oxaliplatin chemotherapy in 246 patients with colon cancer, the total effective rate was 43.90% (108/246). Clinical stage Ⅳ, moderate/well differentiation lymph node metastasis, and GSTP1 genotypes AG and GG were important factors influencing the effect of oxaliplatin chemotherapy in colon cancer patients (P < 0.05). The distribution of TCM syndromes in 118 patients with colon cancer was as follows: Stasis-toxin internal resistance type > Spleen and kidney Yang deficiency type > Qi and blood deficiency type > Damp-heat accumulation type > Liver and kidney Yin deficiency type. There was a statistically significant difference in the distribution of GSTP1 genotypes in patients with blood stasis internal resistance type and Qi and blood deficiency type (P < 0.05). There was a statistically significant difference in the distribution of TCM syndrome types among patients with different GSTP1 genotypes (P < 0.05). The distribution of spleen, lung, and kidney elements of TCM syndromes in patients with different GSTP1 genotypes was significantly different (P < 0.05).

CONCLUSION

There is an association between the GSTP1 gene polymorphism and sensitivity to oxaliplatin and TCM syndrome types in colon cancer patients. Therefore, the detection of GSTP1 gene polymorphism is helpful to evaluate the therapeutic effect in patients receiving oxaliplatin as the basic drug chemotherapy, determine the type of TCM syndrome, and provide scientific guidance for individualized treatment of colon cancer.

CORRELATION ANALYSIS OF GSTP1 GENE POLYMORPHISM WITH MORBIDITY OF PRIMARY METASTATIC COLORECTAL CANCER

Colorectal cancer (CRC) is one of the most common malignancies. Susceptibility to malignant processes is mediated by genetically driven differences in the effectiveness of detoxification of potential carcinogens. One of the factors that may influence the risk of CRC is the glutathione-S-transferase (GST) gene family that encodes glutathione transferase enzymes. The GSTP1 gene is expressed both in normal and pathological conditions. Determining its specific alleles may be a marker of CRC. The aim of the research – to study GSTP1 gene polymorphism, which is likely to be more common among patients with primary metastatic colorectal cancer compared with healthy population. Materials and methods. The study involved 12 patients with primary metastatic colorectal cancer aged 43 to 72 years, the control group was represented by a sample of 31 people without cancer. Results. The incidence of advanced CRC in the presence of GSPT1 Val / Val (aa) polymorphism is statistically significantly higher than in the presence of Ile / Ile (AA) and Ile / Val (Aa) GSPT1 polymorphism. Conclusions. Among people with GSTP1 Val / Val (aa) polymorphism, primary CRC is 4.4 times more likely than among people with GSPT1 Ile / Ile (AA) and Ile / Val (Aa) polymorphisms, which are statistically significant (P < 0.05). The obtained results indicate the possibility of conducting a genetic study of GSTP1 polymorphism to form groups of potential risk of CRC.