A possible involvement of aberrant expression of the FHIT gene in the carcinogenesis of squamous cell carcinoma of the uterine cervix.

To investigate involvement of an aberrant expression of the FHIT (fragile histidine triad) gene in the process of carcinogenesis and progression in cervical carcinoma, we examined its expression by the reverse transcriptase polymerase chain reaction (RT-PCR) and cDNA sequence method in 32 cervical invasive carcinomas (25 squamous cell carcinomas and seven adeno- or adenosquamous carcinomas) and 18 of its precursor lesions [four low-grade and 14 high-grade cervical intraepithelial neoplasias (CINs)]. We also examined a link between the occurrence of the aberrant expression and human papillomavirus (HPV). We detected the aberrant FHIT transcripts in 11 of 25 (44%) cervical invasive squamous cell carcinomas and in 5 of 14 (36%) high-grade CINs (CIN 2 or 3), whereas they were not found in seven non-squamous type and four low-grade CINs (CIN 1). The alteration patterns of the FHIT gene expression in high-grade CINs were virtually similar to those found in invasive carcinomas, such that the exons 5-7 were consistently deleted associated or unassociated with loss of the exon 4 and/or 8. The incidence of the aberrant expression was not related to the presence of HPV and its type. These data indicate that the aberrant expression of the FHIT gene is observed in precursor lesions of cervical carcinoma as well as invasive carcinomas, with its incidence not increasing with advance of clinical stage. Given the squamous cell type dominant expression, the aberrant expression may play a critical role in the generation of squamous cell carcinoma of the uterine cervix, but not the consequence of the progression of the cancer.