Comparison of sequence variations in genes of biotransfromation enzymes in some carcinoma

Xenobiotic biotransformation process and its capacity is crucial for xenobiotic chemicals elimination that may cause damage toward cell structures. The effectiveness of the enzymes included in this process depends on the gene variants that encodes them. The aim of this work was to compare certain polymorphisms of selected genes between cases and control groups. Studied polymorphisms were null genotypes of the glutathione S-transferase gene M1 and T1 and the insertion of TA dinucleotide in the promotor region of UDP-glucuronosyl transferase 1A1. The number of cases group was six included patients with colorectal, lung, prostate, breast, pancreatic and head and neck cancer. Total number of analysed individuals was 1 118 for cancer cases and 470 for healthy controls. The control group was divided into two groups, the first one was called general and the second one was called special included healthy individuals with no cancer history in their closest family members. Gilbert syndrome (GS) is caused by homozygous insertion of the TA dinucleotide in the TATA box of the gene UGT1A1 and it causes elevated bilirubin levels. Bilirubin is a potent antioxidant in human body, so the aim was to attest its protective effect toward cancer. We expected lower frequency of GS as a protective factor in the cases groups compared with controls. This hypothesis was confirmed in the breast cancer group (GS frequency 10,0 %) and pancreatic cancer group (GS frequency 11,1 %). In the general and special control groups the frequency of GS was 16,0 % and 15,4 % respectively. Although the other case groups show lower frequency of GS, the results weren´t statistically significant. Null GSTM1 genotype was observed with 50,4 % frequency in the general control groups and with 55,3 % frequency in the special control group. Neither the one of the cases groups hasn´t showed significantly lower percentage of null genotype. Despite expectation we observed statistically significant lower frequency of null genotype in the group of lung and pancreatic cancer group (37,4 % and 39,3 % respectively). According to this study, we can say that the lack of glutathione S-transferase M1 activity is not a risk factor for cancer development. Null genotype of GSTT1 wasn´t identified in both control groups at all. In case groups of breast and prostate cancer, there was only one individual carrying the null GSTT1 genotype. Statistically significant higher frequency of this polymorphism was observed in patients with colorectal cancer (9,7 %), lung cancer (17,2 %), pancreatic cancer (3,0 %) and head and neck cancer (15,9 %). In these groups the lack of glutathion S-transferase T1 activity might be considered as risk factor for cancer development. Nevertheless, for further verification it needs to take more investigation in this field, especially enlarge the number of patient in the case groups of head and neck, lung and pancreatic cancer