Etiologically, the sporadic colorectal cancer is a complex and multifactorial disease that is linked to both exogenic and endogenic factors.
Accumulating evidence indicates that susceptibility to cancers, including colorectal cancer, is mediated by genetically determined differences in the effectiveness of detoxification of potential carcinogens.
|An Ile105Val amino acid substitution alters variant enzyme efficiency|
|International Journal of Colorectal Diseases|
A member of the glutathione-S-transferase family, glutathione-S-transferase P1 (GSTP1), is involved in susceptibility to carcinogen-associated colorectal cancer.
An A to G transition in exon 5 of the glutathione-S-transferase P1 gene resulting in Ile105Val amino acid substitution has been identified.
This change leads to alteration in catalytic efficiency of variant enzyme.
Dr Tatyana Vlaykova and colleagues from Bulgaria evaluated the influence of Ile105Val glutathione-S-transferase P1 polymorphism on susceptibility to colorectal cancer.
The team conducted the glutathione-S-transferase P1 genotyping in a case-control study of 80 ethnic Bulgarian colorectal cancer patients.
In addition, the investigators assessed 126 unaffected controls using polymerase chain reaction restriction fragment length polymorphism method.
The investigative team observed a statistically significant case-control difference in genotype frequencies.
The difference in genotype frequencies were 0.7 vs 0.5 for Ile/Ile, 0.2 vs 0.4 for Ile/Val, and 0.09 vs 0.07 for Val/Val in cases and controls, respectively.
The odds ratio for Val/Val was close to 1, whereas the odds ratio for Ile/Val was significantly lower at 0.5, compared to the referent Ile/Ile genotype.
The team noted that allele frequencies did not show a significant difference between cases and controls.
Dr Vlaykova's team concluded, "Based on the obtained protective effect of Ile/Val glutathione-S-transferase P1 genotype, we could suggest that Ile105Val glutathione-S-transferase P1 polymorphism may play some role in susceptibility to colorectal cancer."