Downregulation of p21/WAF1 is related to advanced and dedifferentiated laryngeal squamous cell carcinoma

Aim-To analyse p21/WAF1 expression and its relation to p53, apoptosis, cell proliferation, clinicopathological characteristics, and patient survival in human laryngeal squamous cell carcinoma. Methods-Primary tumours for analyses were obtained from 172 patients with complete follow up data. All patients were treated between 1975 and 1995. Immunohistochemistry was used to evaluate the expression of p21/WAF1, bcl-2, and p53 proteins. The proliferative activity was determined using Ki67 and PCNA antibodies as well as volume corrected mitotic count (M/V index). Volume corrected apoptotic count (AN index) was determined using an enzymatic in situ cell death detection kit based on the TUNEL method. Results-High p21 expression was significantly related to high p53 and normal bcl-2 expressions as well as low mitotic count. No association was noticed between p21 expression and apoptotic rate. A significant inverse correlation between p21 expression and advanced stage and poor differentiation was observed, but p21 expression showed no correlation with survival. Conclusions-The expression of p21 was associated with tumour stage, histopathological grade, node status, and mitotic count, which may indicate a role for p21 in the progression of laryngeal squamous cell carcinoma.