Andrew Borkowski

bcl-2/bax RATIO AS A PREDICTIVE MARKER FOR THERAPEUTIC RESPONSE TO RADIOTHERAPY IN PATIENTS WITH PROSTATE CANCER

OBJECTIVES Markers predictive of therapeutic response of prostatic tumors to radiotherapy may have major significance in optimizing effective treatment of prostate cancer. Because inherent cellular radioresistance plays a critical role in the failure of radiotherapy, in this study, we investigated whether there is a correlation between the ratio of two apoptosis regulators, bcl-2 (apoptosis suppressor) and bax (apoptosis inducer) in prostatic tumors and the clinical response to radiotherapy in patients with localized prostate cancer. METHODS A retrospective review of records of 41 patients who underwent external beam radiotherapy for prostate cancer was conducted. On the basis of post-treatment prostate biopsy and prostate-specific antigen (PSA) criteria, the cancers of 20 patients were classified as radiation nonresponders and 21 as radiation responders. Immunohistochemical analysis was performed on paraffin-embedded prostate sections to determine the level of expression of the two apoptotic proteins, bcl-2 and bax, in tumor cells. RESULTS bcl-2 immunoreactivity was significantly higher in prostatic tumors not responsive to radiotherapy (38.6+/-4.1), compared with the radiation responders (24.1+/-4.6) (P <0.001). Expression of bax protein was lower in nonresponders, but values were not significantly different from the responders. The resulting significantly higher bcl-2/bax ratio (P <0.01) correlated with poor therapeutic responsiveness of prostate cancer to radiotherapy (1.12+/-0.12 and 0.56+/-0.13, for nonresponders and responders, respectively). This correlation (r=0.67) was independent of age, PSA, and Gleason score. CONCLUSIONS These findings suggest that patients with an elevated bcl-2/bax ratio are at increased risk of their cancer failing to respond to radiotherapy. This study suggests a predictive value for the bcl-2/bax ratio as a potential molecular marker for predicting radioresistance of prostatic tumors.

INDUCTION OF PROSTATE APOPTOSIS BY DOXAZOSIN IN BENIGN PROSTATIC HYPERPLASIA

PURPOSE The molecular mechanisms underlying the therapeutic effect of the alpha1 blocker, doxazosin, on benign prostatic hyperplasia (BPH) are poorly understood. We evaluated the effect of doxazosin on cell proliferation and apoptosis in the prostatic glandular epithelium and stroma of patients with BPH. MATERIALS AND METHODS We examined proliferative and apoptotic activities in prostate specimens of 22 men a mean of 65 years old with BPH before and after doxazosin treatment within the normal therapeutic range. Proliferative and apoptotic indexes were determined using Ki-67 nuclear antigen staining and the terminal transferase end labeling assay, respectively. The smooth muscle cell content in prostatic specimens was identified by smooth muscle alpha-actin, and desmin immunoreactivity and apoptotic indexes were correlated with prostatic stromal tissue regression and improvement in BPH symptoms. RESULTS In response to doxazosin treatment there were no significant changes in the kinetics of cell proliferation in the prostatic epithelial or stromal cell population. Mean pretreatment baseline apoptosis was 1.9 and 1.0% for the epithelial and stromal prostate components, respectively. Mean apoptotic indexes significantly increased after 3 months of doxazosin treatment in the glandular epithelial (6%) and smooth muscle cells (15%). By 12 months after treatment epithelial apoptosis had decreased to constitutive levels, while the apoptotic index of prostatic stroma cells remained high. Doxazosin induced smooth muscle cell apoptosis correlated with prostatic stromal degeneration, decreased alpha-smooth muscle actin expression and improved BPH symptoms. CONCLUSIONS These findings implicate the induction of prostate apoptosis by doxazosin as a potential molecular mechanism underlying the acute and chronic therapeutic responses of BPH to alpha1 blockade.

Loss of Cell Cycle Regulators p27Kip1 and Cyclin E in Transitional Cell Carcinoma of the Bladder Correlates with Tumor Grade and Patient Survival

The cyclin-dependent kinase inhibitor p27Kip1 is a powerful molecular determinant of cell cycle progression. Loss of expression of p27Kip1 has been shown to be predictive of disease progression in several human malignancies. In this study we investigated the expression of two key cell cycle regulators, p27Kip1 and cyclin E, in the progression of transitional cell carcinoma of the bladder. An immunohistochemical analysis was conducted in a series of 50 bladder tumor specimens, including 3 metastatic lymph nodes, and 7 normal bladder specimens, using specific antibodies against the two regulators of the cell cycle, p27Kip1 and cyclin E. The degree of immunoreactivity was correlated with the pathological tumor grade, stage, and patient survival. A uniformly intense immunoreactivity for p27Kip1 and cyclin E was observed in epithelial cells of normal bladder tissue. Malignant bladder tissue demonstrated a heterogeneous pattern of significantly reduced p27Kip1 and cyclin E immunoreactivity, compared with normal urothelium (P < 0.01). In addition, there was progressive loss of expression of both cell cycle proteins with increasing tumor grade and pathological stage. Expression of p27Kip1 was significantly lower in the poorly differentiated tumors (grades III) compared to well and moderately differentiated (grades I and II) tumors (P = 0.004). Moreover, the expression of cyclin E was lower in grade III tumors compared to grade I and II lesions, although this difference failed to reach statistical significance. Most significantly, Kaplan-Meier plots of patient survival show increased mortality risk associated with low levels of p27Kip1 (P = 0.001) and cyclin E (P = 0.002) expression. This is the first evidence that loss of expression of p27Kip1 and cyclin E in human bladder transitional cell carcinoma cells correlates with advancing histological aggressiveness and poor patient survival. These results have clinical importance, because they support a role for p27Kip1 and cyclin E as novel predictive markers of the biological potential of bladder tumors that will enable identification of those tumors most likely to progress to muscle invasive disease and of patient survival.

Combined effect of terazosin and finasteride on apoptosis, cell proliferation, and transforming growth factor‐β expression in benign prostatic hyperplasia

Medical treatment of benign prostatic hyperplasia (BPH) targets relief of symptoms by causing either relaxation of the prostatic smooth muscle with α1 adrenergic blockade, or shrinkage of the gland with 5α‐reductase inhibitors. We recently demonstrated that α1‐blockers, such as terazosin, induce apoptosis in prostatic cells. In this study, we examined the combined effect of finasteride and terazosin on the rate of apoptosis and cellular proliferation to investigate their potential synergy at the cellular level.

Racial differences in prostate cancer growth : Apoptosis and cell proliferation in Caucasian and African-American patients

Epidemiologic evidence reveals striking racial differences in incidence and clinical behavior of prostate cancer among American men. In this study, we assessed the incidence of apoptosis and cell proliferation in prostate cancer specimens from African‐American and Caucasian patients in an attempt to identify potential differences in tumor growth determinants between the two ethnic groups.

Intranet-Based Quality Improvement Documentation at the Veterans Affairs Maryland Health Care System

The Pathology and Laboratory Medicine Service of the Veterans Affairs Maryland Health Care System is inspected biannually by the College of American Pathologists (CAP). As of the year 2000, all documentation in the Anatomic Pathology Section is available to all staff through the VA Intranet. Signed, supporting paper documents are on file in the office of the department chair. For the year 2000 CAP inspection, inspectors conducted their document review by use of these Web-based documents, in which each CAP question had a hyperlink to the corresponding section of the procedure manual. Thus inspectors were able to locate the documents relevant to each question quickly and efficiently. The procedure manuals consist of 87 procedures for surgical pathology, 52 procedures for cytopathology, and 25 procedures for autopsy pathology. Each CAP question requiring documentation had from one to three hyperlinks to the corresponding section of the procedure manual. Intranet documentation allows for easier sharing among decentralized institutions and for centralized updates of the laboratory documentation. These documents can be upgraded to allow for multimedia presentations, including text search for key words, hyperlinks to other documents, and images, audio, and video. Use of Web-based documents can improve the efficiency of the inspection process.

LOSS OF CELL-CYCLE REGULATORS p27Kip1 AND CYCLIN E IN TRANSITIONAL CELL CARCINOMA OF THE BLADDER CORRELATES WITH TUMOR GRADE AND PATIENT SURVIVAL

The cyclin-dependent kinase inhibitor p27(Kip1) is a powerful molecular determinant of cell cycle progression. Loss of expression of p27(Kip1) has been shown to be predictive of disease progression in several human malignancies. In this study we investigated the expression of two key cell cycle regulators, p27(Kip1) and cyclin E, in the progression of transitional cell carcinoma of the bladder. An immunohistochemical analysis was conducted in a series of 50 bladder tumor specimens, including 3 metastatic lymph nodes, and 7 normal bladder specimens, using specific antibodies against the two regulators of the cell cycle, p27(Kip1) and cyclin E. The degree of immunoreactivity was correlated with the pathological tumor grade, stage, and patient survival. A uniformly intense immunoreactivity for p27(Kip1) and cyclin E was observed in epithelial cells of normal bladder tissue. Malignant bladder tissue demonstrated a heterogeneous pattern of significantly reduced p27(Kip1) and cyclin E immunoreactivity, compared with normal urothelium (P < 0.01). In addition, there was progressive loss of expression of both cell cycle proteins with increasing tumor grade and pathological stage. Expression of p27(Kip1) was significantly lower in the poorly differentiated tumors (grades III) compared to well and moderately differentiated (grades I and II) tumors (P = 0.004). Moreover, the expression of cyclin E was lower in grade III tumors compared to grade I and II lesions, although this difference failed to reach statistical significance. Most significantly, Kaplan-Meier plots of patient survival show increased mortality risk associated with low levels of p27(Kip1) (P = 0.001) and cyclin E (P = 0.002) expression. This is the first evidence that loss of expression of p27(Kip1) and cyclin E in human bladder transitional cell carcinoma cells correlates with advancing histological aggressiveness and poor patient survival. These results have clinical importance, because they support a role for p27(Kip1) and cyclin E as novel predictive markers of the biological potential of bladder tumors that will enable identification of those tumors most likely to progress to muscle invasive disease and of patient survival.