pRb2/p130 protein expression is correlated with clinicopathologic findings in patients with oral squamous cell carcinoma

BACKGROUND pRb2/p130 is one of the retinoblastoma (Rb) gene family and a suppressor oncogene. Immunohistochemically, the expression of pRb2/p130 was reported to be correlated inversely with the degree of malignancy in lung carcinoma and endometrial carcinoma. In the current study, the correlation between expression of pRb2/p130 and clinicopathologic factors in oral squamous cell carcinoma was investigated. METHODS One hundred twenty-two specimens from patients with oral squamous cell carcinoma were investigated by staining with a polyclonal antibody against pRb2/p130. The correlation between the expression of pRb2/p130 and various clinicopathologic factors was studied. RESULTS Positive staining for pRb2/p130 was observed in 61 of 122 cases (50.0%). pRb2/p130 expression was found to be correlated significantly with clinical stage (P = 0.050), cervical lymph node metastasis (P = 0.035), and tumor differentiation (P = 0.050). In the entire group a significantly reduced 5-year cumulative survival rate was observed in patients with pRb2/p130-negative tumors compared with patients whose tumors positively expressed pRb2/p130 (P = 0.0004). When tested with Cox proportional hazards regression analysis, the most significant independent prognostic factor for the entire group of 122 patients was found to be pRb2/p130 expression. CONCLUSIONS Expression of pRb2/p130 may be a good prognostic indicator in patients with oral squamous cell carcinoma and also may be utilized for the subclassification of tumors with the Grade 3 mode of carcinoma invasion. Cancer 2001;92:2117–25. © 2001 American Cancer Society.