Transforming growth factor (TGF)-beta1 gene common polymorphisms and plasma TGF-beta1 levels in patients with lung cancer

Abstract

Transforming growth factor (TGF)-b1 is known to regulate many cellular processes, including cell proliferation, differentiation, and apoptosis. Plasma TGF-b1 levels has been shown to be elevated in patients with lung cancer. In this study, we test the association of the polymorphisms at 2 loci, i.e. nucleotide position -509 in the promoter region (C-509T), and nucleotide position 869 relative to the transcription initiation site (T869C) of the TGF-b1 gene using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and measure the plasma TGF-b1 levels. TGF-b1 genotype and allele frequencies were not significantly different for patients with lung cancer (n = 102) and controls (nonsmokers, n = 140 or smokers, n = 116). The odds ratio of the TGF-b1 C allele at nucleotide position 869 was 0.51 (95% confidence interval 0.25 to 1.06; P = 0.0827) for patients and nonsmoking controls and 0.49 (95% confidence interval 0.23 to 1.03; P = 0.0702) for patients and smoking controls in a dominant model (TC + CC versus TT), close to reach significant level. The patients group showed significant higher plasma TGF-b1 levels across different genotypes (1852 ± 123 pg/ml vs. 3422 ± 158 pg/ml for nonsmoking controls and patients respectively). There was no difference in plasma TGF-b1 levels between smoking controls and patients. Our results suggest that TGF-b1 polymorphisms do not play a role in the pathogenesis of lung cancer, even though there remains the possibility of a lower incidence of lung cancer for polymorphism at nucleotide position 869, which need further investigation. (Supported by a University of Hong Kong, URC/CRCG Research Grant.)