Bcl-2 and bax expression and prostate cancer outcome in men treated with radiotherapy in Radiation Therapy Oncology Group protocol 86-10
- Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA (United States)
- Radiation Therapy Oncology Group, American College of Radiology, Philadelphia, PA (United States)
- Pathology, Baylor College of Medicine, Houston, TX (United States)
- Pathology, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States)
- Pathology, LDS Hospital, Intermountain Health Care, Salt Lake City, UT (United States)
- Radiation, LDS Hospital, Salt Lake City, UT (United States)
- Radiation Oncology, University of California, Los Angeles, CA (United States)
- Radiation Oncology, University of Rochester Medical Center, Rochester, NY (United States)
- Radiation Oncology, University of Michigan Medical Center, Ann Arbor, MI (United States)
Purpose: Bcl-2 and bax are proteins with opposing roles in apoptosis regulation; yet abnormal expression of either has been associated with failure after radiotherapy (RT). In this study we examined bcl-2 and bax expression as predictive markers in men treated with radiotherapy {+-} androgen deprivation on Radiation Therapy Oncology Group (RTOG) protocol 86-10. Experimental Design: Suitable archival diagnostic tissue was obtained from 119 (26%) patients for bcl-2 analysis and 104 (23%) patients for bax analysis. Cox proportional hazards multivariate analysis was used to determine the relationship of abnormal bcl-2 and bax expression to the end points of local failure, distant metastasis, cause-specific mortality, and overall mortality. Bcl-2 overexpression was classified as any tumor cell cytoplasmic staining and altered bax expression was classified as greater or lesser cytoplasmic staining intensity of tumor cells as compared with adjacent normal prostate epithelium. Results: The study cohort exhibited bcl-2 overexpression in 26% (n = 30) of cases and abnormal bax expression in 47% (n = 49) of cases. A borderline significant relationship was observed between abnormal bax expression and higher Gleason score (p = 0.08). In univariate and multivariate analyses, there was no statistically significant relationship seen between abnormal bcl-2 or bax expression and outcome. Conclusions: Abnormal bcl-2 and bax expression were not related to any of the end points tested. The cohort examined was comprised of patients with locally advanced disease and it is possible that these markers may be of greater value in men with earlier-stage prostate cancer.
- OSTI ID:
- 20850049
- Journal Information:
- International Journal of Radiation Oncology, Biology and Physics, Vol. 66, Issue 1; Other Information: DOI: 10.1016/j.ijrobp.2006.03.056; PII: S0360-3016(06)00698-5; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0360-3016
- Country of Publication:
- United States
- Language:
- English
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