[The role of oncogenic human papillomaviruses in tonsillar squamous cell carcinomas with functional inactivation of the retinoblastoma protein].

In order to identify squamous cell carcinomas of the head and neck (HNSCC) with common biological and clinical features, we investigated the incidence and properties of carcinomas lacking retinoblastoma protein (pR6) cell cycle control. Of 208 HNSCC investigated, 23 (11%) showed a lack of pRb expression. The majority of these tumors (65%) were tonsillar carcinomas. The pRb-negative tonsillar tumors were all stage IV, had metastasized to lymph nodes at the time of diagnosis and were in general poorly differentiated or undifferentiated. Very significantly, the pRb-negative phenotype was strongly associated with the presence of oncogenic human papilloma viruses, implying a viral etiology and functional inactivation of pRb by the viral E7 oncoprotein. Despite the very adverse histopathological factors, patients with pRb-negative tonsillar carcinomas had a better clinical outcome, which was consistent with a uniform favorable responsiveness of these tumors to postoperative radiation therapy.