Résumé
Objective The aim of this study was to investigate the methylation status of fragile histidine triad( FHIT) gene, human mutl homolog 1(hMLH1)gene,p16 gene,retinoic acid receptor beta( RAR-beta) gene,Reprimo gene and tissue inhibitor of metalloproteinase 3 ( Timp3) gene in gastric cancer and corresponding paracancerous tissues. Methods The methylation levels of FHIT,hMLH1,p16,RAR-beta,Reprimo and TIMP3 genes in 42 clinically resected gastric cancer specimens and 42 corresponding paracancerous tissues were detected by sodium bisulfite sequencing. Results The average methylation rates of the genes in gastric cancer and corresponding paracancerous tissues were:FHIT(1. 50% ,1. 36% ),hMLH1(4. 77% ,0. 48% ),p16(9. 63% ,10. 36% ), RAR-beta(4. 75% ,4. 17% ),Reprimo(9. 71% ,3. 76% )and TIMP3 genes(18. 34% ,14. 06% ). Compared with the paracancerous control group,the average methylation rate of Reprimo gene was only statistically different in gastric cancer patients(P=0. 00787). The difference in methylation rate of Reprimo gene promoter in gastric cancer patients with the degree of tissue differentiation was sta-tistically significant(P<0. 05). Conclusion There has methylation in the cytosine guanidine dinucleotide island of the Reprimo gene promoter region in gastric cancer. The high methylation rate of the Reprimo gene can be used as a potential biomarker for gastric cancer to detect the early stage of gastric cancer.
Résumé
Colorectal cancer is one of the common malignant tumors and the overall prognosis is poor. The search for a more effective treatment for colorectal cancer has never stopped. The current interaction between the modulated immune system and the tumor microenvironment is a hot topic in the treatment of colorectal cancer. The achievements involve immune checkpoint inhibition, cytokine therapy, toll?like receptors and autologous cell therapy. It has been proved that these methods have mild effect on tumor loading reduction. However, significant breakthrough has been achieved with the use of checkpoint inhibitors targeting cytotoxic T lymphocyte associated antigen?4 (CTLA?4),programmed death?1 (PD?1) and programmed death receptor ligand 1 (PD?L1). Immunotherapy is promising in the treatment of patients with refractory tumors. The success of this current immunotherapy approach is largely limited to tumors with high mutation amplification, such as melanoma,renal cell carcinoma ( RCC) and non?small cell lung cancer. However,this discovery has led the development of checkpoint inhibitors in the treatment of colorectal cancer with highly mutated amplification of mismatch repair gene to a new era.