LOCALLY RECURRENT PROSTATE TUMORS FOLLOWING EITHER RADIATION THERAPY OR RADICAL PROSTATECTOMY HAVE CHANGES IN KI-67 LABELING INDEX, P53 AND BCL-2 IMMUNOREACTIVITY

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Abstract
Purpose: We compare the biological phenotype of recurrent prostatic tumors after definitive local therapy (radiation or radical prostatectomy) with that of the same tumors before treatment. Materials and Methods: Cellular proliferation (Ki-67 labeling index), p53 nuclear reactivity and bcl-2 immunoreactivity were determined in pretreatment and posttreatment tumor specimens from 13 patients with local tumor recurrence following radiation, and in 18 patients with local tumor recurrence following radical prostatectomy. Results: Mean Ki-67 labeling index increased approximately 2-fold in locally recurrent tumors after radiation (10.5 versus 5.6%, p = 0.0008) or surgery (6.0 versus 3.2%, p = 0.0025) when compared with pretreatment tumors. We noted p53 nuclear reactivity in a significantly higher proportion of recurrences than in pretreatment tumors following radiation (54 versus 8%, p = 0.032) and surgery (39 versus 5%, p = 0.022). Although bcl-2 immunoreactivity was also seen in a higher proportion of recurrent tumors, this difference did not reach statistical significance for either radiation or surgery. Conclusions: Recurrent tumors following either radiation or surgery differ significantly from the corresponding pretreatment tumors with respect to cellular proliferation and p53 nuclear reactivity.