Objective: To study the RB1 gene in squamous cell carcinoma of larynx(ISCC) and to find clue for discovering and locating new suppressor gene.
Methods: Loss of heterozygosity (LOH) of microsatellite polymorphic sequence on chromosomes 13 at RB1.20 locus of 58 LSCC patients were analyzed. The p110RB1 protein state was detected by immunohistochemical staining using the polyclonal antibody to the RB1 products.
Results: It showed that 3 cases in the preinvasive stage (i.e. carcinoma in situ) had no any LOH on chromosome 13. Forty percent of the 55 invasive LSCC showed LOH at RB1.20 locus. By immunohistochemical staining p110RB1 protein negative reaction was observed in 8 LSCCs in which 6 cases associated with LOH at RB1.20 locus.
Conclusions: RB1 gene was inactivated in some LSCCs. It is putative that there is another tumor suppressor gene on chromosome 13 near by RB1.20 locas. The inactivation of the genes at the chromosome 13q region including RB1 involved genesis and development of invasive LSCC.