Association of gastric cancer with tyrosine hydroxylase gene polymorphism in a northwestern Chinese population.

Gastric cancer (GC) is a common and complex disease caused by multifactors. The aim of our study was to investigate the association of the common polymorphisms detected in insulin-like growth factor (IGF)-II, IGF-1 receptor, insulin-like growth factor binding protein 1 (IGFBP1), insulin (INS) and tyrosine hydroxylase (TH) with susceptibility to GC in a northwestern Chinese population. One hundred and fifty-four GC patients and 166 healthy controls were investigated in our study. The genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism. The frequencies of CC and CT genotypes of TH were significantly higher in GC patients than in controls, as the odds ratios were 3.03 (95%CI 1.438-6.362, P=0.003) and 1.97 (95%CI 1.218-3.167, P=0.005), respectively. No association was found between the polymorphisms of IGF-II ApaI, insulin-like growth factor-1 receptor MnlI, IGFBP1 Bgl II and INS-23HphI and the development of GC. The presence of CC and CT genotypes of TH was associated with a significantly increased risk of GC. But the polymorphisms of other genes detected did not indicate an increased risk of GC in the investigated population.