Frequent FHIT gene loss of heterozygosity in human papillomavirus-infected non-smoking female lung cancer in Taiwan

The fragile histidine triad (FHIT), located in chromosome region 3p14.2, had been reported to be a frequent allele with loss of heterozygosity (LOH) in smoking lung cancer and HPV-associated cervical cancer. Additionally, FHIT LOH may act as a tumor suppressor gene to involve in smoking-related lung tumorigenesis and HPV-related cervical tumorigenesis, respectively. In our previous report, a high prevalence of HPV 16/18 infection has been observed in non-smoking female lung cancer patients, and thus it was speculated that HPV 16/18 infection may increase the LOH frequency of FHIT in female cases to implicate in lung tumorigenesis. In this study, 157 lung cancer patients were enrolled and subjected to FHIT LOH analysis with three microsatellite markers. As expected, the frequency of FHIT LOH in males, smokers, and squamous cell carcinomas lung cancer patients was significantly higher than that of their corresponding counterpart (P=0.020 for gender, P<0.001 for smoking status, and P=0.038 for tumor type). Interestingly, a correlation between HPV 16 infection and FHIT LOH was observed in female lung cancer cases. To be more specifically, FHIT LOH frequency was remarkably increased from 18% (6 of 33) in HPV 16 non-infected female cases to 46% (11 of 24) in HPV 16 infected cases. The higher frequency of FHIT LOH observed in HPV 16-infected female lung tumors suggested that the involvement of HPV infection in lung tumorigenesis may, at least in part, be mediated through FHIT LOH.