Loss of FHIT expression in squamous cell carcinoma and premalignant lesions of the larynx

The tumor suppressor gene FHIT (fragile histidine triad) at chromosomal position 3p14.2 is altered by deletions in human tumors. The frequency and specificity of its inactivation vary among carcinomas, but few articles have referred to premalignant lesions such as dysplasia. We studied the expression of FHIT in a series of squamous cell carcinomas and premalignant lesions of the larynx. We observed 36 laryngeal carcinoma biopsy specimens and 70 dysplasia biopsy specimens. We studied FHIT expression in carcinoma and dysplasia with the immunohistochemical ABC (avidin-biotinylated peroxidase complex) method. Loss of FHIT protein was observed in 42% of the squamous cell carcinomas and 23% of the premalignant lesions. There was no significant difference among the three grades of dysplasia in FHIT expression. These findings of loss of FHIT protein expression, not only in squamous cell carcinoma, but also in premalignant lesions, indicate that FHIT alterations play an important role in the early events of carcinogenesis.