Association between high initial tissue levels of cyclin D1 and recurrence of nasopharyngeal carcinoma

Objectives/Hypothesis: Cyclin D1 expression and the rate of apoptosis have been reported to serve as important prognostic indicators in human cancers. The purpose of the present study was to determine the prognostic significance of both initial cyclin D1 expression and the apoptotic index in nasopharyngeal carcinoma. Study Design: Cohort study. Methods: Cyclin D1 protein levels and apoptosis in tumors and their corresponding adjacent, histologically normal tissues were determined at the time of initial diagnosis using immunohistochemical staining. Western blot analysis, and in situ end labeling, respectively, in 64 patients with T1-T4/N0-N2, poorly differentiated squamous cell carcinoma of the nasopharynx. All cases were treated by routine radiation therapy with a total median dose of 70 Gy and followed up for 10 years. Results: High levels of cyclin D1 were found in 35 of 64 tumor specimens (54.7%); no cyclin D1-positive cells were determinable in normal epithelium of the nasopharynx. Rates of early local recurrence (within 5 y) were significantly higher (P <.01) for patients with high levels of cyclin 131 before radiation therapy (24 of 35 patients [68.6%]) as compared with patients with low or no expression (3 of 29 [10.3%]). Furthermore, patients bearing high levels of cyclin 131 had a poorer prognosis concerning 10-year survival than the others (P <.001), whereas overexpression of cyclin D1 did not correlate with the initial TMN classification (P >.05). According to the rate of spontaneous apoptosis in tumors below or above the median, patients were divided into two groups. There was no statistically significant difference for the overall survival between the two groups (P >.05). Conclusions: The present study demonstrates that cyclin D1 can be used as an indicator of recurrence and subsequent prognosis in nasopharyngeal carcinoma after radiation therapy. At the same time, the apoptotic state before radiation therapy is of no value in predicting the prognosis of patients with nasopharyngeal carcinoma.