Bcl-2 is significantly overexpressed in localized radio-recurrent prostate carcinoma, compared with localized radio-naive prostate carcinoma.
OBJECTIVE
We set out to determine whether patients who underwent prostatectomy for recurrence after external-beam radiotherapy for prostate cancer had a higher incidence of alterations in the apoptotic pathway than did patients who underwent surgery as initial treatment.


METHODS
Twenty patients who underwent unsuccessful full-dose external-beam radiotherapy for prostate cancer and subsequently underwent salvage radical surgery (radio-recurrent group), and 20 patients matched for various clinical parameters who underwent only radical prostatectomy for localized or locally advanced prostate cancer (radio-naive group), were studied. Tissue samples were examined for immunoreactivity for p53, p21, Bcl-2, and Ki-67 proteins. Statistically, the two groups were compared using exact logistic regression.


RESULTS
Fifty-five percent of the tumors from patients initially treated with radiotherapy were noted to overexpress Bcl-2; whereas, in the radio-naive group, no patient had Bcl-2 overexpression (p = 0.0004). More patients who underwent salvage radical surgery were found to have a higher mean proliferative index (Ki-67 staining) (39.6%), compared with patients undergoing prostatectomy alone (22.1%), p = 0.0800. No significant difference was noted in immunohistochemical expression of p53 and p21 between the two groups.


CONCLUSIONS
Patients undergoing radical prostatectomy after radiotherapy had a significantly higher rate of Bcl-2 overexpression than did patients who underwent surgery as the initial treatment. Alterations in the apoptotic pathway may be important in the development of local recurrence after radiation therapy.
Rosser
Charles J
CJ
Department of Urology, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA.
Reyes
Adriana O
AO
Vakar-Lopez
Funda
F
Levy
Lawrence B
LB
Kuban
Deborah A
DA
Hoover
David C
DC
Lee
Andrew K
AK
Pisters
Louis L
LL
D000230:Adenocarcinoma / Q000097:blood / Q000235:genetics* / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood; D015331:Cohort Studies; D003131:Combined Modality Therapy; D015653:Cystectomy; D015972:Gene Expression Regulation, Neoplastic / Q000528:radiation effects*; D019254:Genes, bcl-2; D016158:Genes, p53; D006801:Humans; D019394:Ki-67 Antigen / Q000096:biosynthesis / Q000235:genetics; D008297:Male; D008875:Middle Aged; D008940:Mitotic Index; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000097:blood / Q000235:genetics; D009364:Neoplasm Recurrence, Local / Q000209:etiology* / Q000378:metabolism; D017430:Prostate-Specific Antigen / Q000097:blood; D011468:Prostatectomy / Q000379:methods; D011471:Prostatic Neoplasms / Q000097:blood / Q000235:genetics* / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis*; D018714:Radiotherapy, Adjuvant; D016879:Salvage Therapy; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis
D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen; D009363:Neoplasm Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D017430:Prostate-Specific Antigen