| Abstract: | A consistently increased incidence of malignancies in renal transplant recipients has been attributed to the effect of chronic immunosuppression required to prevent transplant rejection. Tumors arising in such patients offer a unique opportunity to study the interactions of the immune system and tumor development. A series of three cases of head and neck squamous cell carcinoma arising in patients after renal, cardiac, or bone marrow transplantation are reported. Patient ages at tumor diagnosis were 18, 29, and 53 years, respectively. Time from transplant to diagnosis of tumor ranged from 7 months to 12 years. Only the youngest patient lacked a history of exposure to the traditional predisposing factors of tobacco and alcohol use. Histo-pathologic examination in all three tumors showed features of koilocytosis with hyperkeratosis and parakeratosis suggestive of papillomavirus infection. Squamous carcinoma cells from one of these patients have been successfully established in cell culture. Immune system impairments secondary to the use of antirejection drugs could allow the expression of oncogenic viruses. A recent report of human papillomavirus (HPV) DNA in a primary and metastatic perianal squamous cell carcinoma from a renal transplant recipient, as well as the reported presence of HPV in benign and malignant neoplasms of the upper aerodigestive tract suggests that HPV infection could play a role in the development of squamous carcinomas in transplant recipients. Further studies of HPV invection in cultured cell lines derived from head and neck tumors occurring in immunosup-pressed patients are needed to define this relationship. |
