Altered patterns of retinoblastoma gene product expression in benign, premalignant and malignant epithelium of the larynx: An immunohistochemical study including correlation with p53, bcl-2 and proliferating indices

In order to study the altered Rb, bcl-2 and p53 proteins expression during laryngeal carcinogenesis and to elucidate the role of these molecules in th e development and progression of the lesions, we have examined the immunohi stochemical expression of these mn,markers in a series of 41 squamous cell carcinomas, 14 cases of in situ carcinoma, 47 with epithelial dysplasia, 11 papillomas and 20 cases of keratosis. Rb protein was expressed in 69.7% (> 5% positive neoplastic cells) of squamous cell carcinomas and p53 in 40% (> 5% positive cells). There was a strong statistically significant difference for Rb, Ki-67 and PCNA immunostaining between malignant, premalignant and benign lesions, increasing from keratosis, papillomas, dysplasia to carcino ma in situ or infiltrating squamous Ca.. Rb protein expression was also str ongly correlated with p53, Ki-67 and PCNA, while p53 protein was strongly c on elated with Ki-67 (p=0023) and PCNA (p=0.0031) indices, in all lesions. In conclusion Rb and p53 altered proteins expression seems to play nit acti ve role in laryngeal carcinogenesis, probably from the early phase, and is correlated with proliferative activity. Also, Rb protein expression is corr elated with the progression of the lesion and could be considered as indica tion of poor prognosis in laryngeal lesions.