UDP glucuronosyltransferase (UGT1A7) gene polymorphisms increase the risk of chronic pancreatitis and pancreatic cancer.

BACKGROUND & AIMS: Chronic pancreatitis and pancreatic adenocarcinoma are associated with alcohol abuse, consumption of tobacco smoke, and environmental aromatic hydrocarbon exposure. The role of genetic factors is incompletely defined. Uridine 5'-diphosphate glucuronosyltransferases are phase II detoxifying enzymes capable of tobacco-borne toxicant inactivation and cellular protection. This study analyzes UGT1A7 gene polymorphisms in pancreatic diseases.

METHODS

Genomic DNA from northern German white patients with pancreatic adenocarcinoma (n = 52) and chronic pancreatitis (n = 146), as well as healthy blood donors (n = 235) was analyzed by UGT1A7-specific PCR, sequencing analysis, and temperature gradient gel electrophoresis. Pancreatic expression of UGT1A genes was identified by duplex reverse-transcription PCR.

RESULTS

Predominant expression of the UGT1A7 gene was identified in human pancreatic tissue. Pancreatic adenocarcinoma was associated with the low detoxification activity UGT1A73 allele, which combines the W208R, N129K, and R131K mutations (odds ratio [OR], 1.98; 95% confidence interval [CI ], 1.24-3.14; P = 0.003). The association of UGT1A73 was especially strong in smokers with pancreatic carcinoma who were younger than 55 years (OR, 4.7; 95% CI, 1.9-11.8; P = 0.0009). Chronic pancreatitis was also associated with UGT1A73 (OR, 1.76; 95% CI, 1.26-2.46; P = 0.0009). UGT1A73 was specifically associated with the subgroup of patients with alcoholic pancreatitis, of whom 89% were smokers (OR, 2.24; 95% CI, 1.46-3.43; P = 0.0001) but was not associated with the nonalcoholic pancreatitis subgroup.

CONCLUSIONS

The UGT1A7 gene is predominantly expressed in human pancreas. The low detoxification activity UGT1A7*3 allele is identified as a novel risk factor of pancreatic diseases defining the interaction of genetic predisposition and environmentally induced oxidative injury.