Altered expreion of rb and p53 in uveal melanoma following plaque radiotherapy

PURPOE : To examine the expreion of protein in the Rb and p53 tumor uppreor pathway in uveal melanoma following plaque radiotherapy. METHOD : Immunohitochemitry and cell culture tudie. Immunohitochemitry for Rb, p16, cyclin D1, p53, HDM2, and Bcl-2 wa performed on twelve eye containing poterior uveal melanoma that were enucleated following plaque radiotherapy. Cell culture tudie were performed in three cae. REULT : The irradiated eye were enucleated for radiation complication (five cae), local tumor recurrence (three cae), and other reaon (four cae). On hitopathologic examination, all cae howed evidence of tumor cell lo. However, reidual tumor cell were preent in all cae, including thoe that were clinically regreed. Reidual cell from three of the clinically regreed cae were cultured and demontrated minimal cell diviion, marked cell death, and extenive chromoomal damage. trong p53 taining wa oberved in ix cae (50%) and wa ignificantly aociated with recent radiotherapy (P = .04). Abnormal cytoplamic taining for Rb wa oberved in four cae (33%). CONCLUION : Plaque radiotherapy of uveal melanoma induce DNA damage, inhibit cell diviion, and promote cell death. Thee change may be due, at leat in part, to induction of p53, which activate gene involved in both cell cycle arret and apoptoi. Plaque radiotherapy can alo caue alteration in the expreion of Rb, but the ignificance of thi finding will require further tudy.