Superficial bladder tumors and increased reactivity against mycobacterial antigens before bacillus Calmette-Guerin therapy

HSP90 expression: a new predictive factor for BCG response in stage Ta-T1 grade 3 bladder tumours

OBJECTIVES

Although Bacillus Calmette-Guérin (BCG) instillations are considered as the adjuvant treatment of choice for stage Ta-T1 grade G3 bladder tumours, there is no consensus for a predictive factor to assess BCG success. This study attempted to evaluate if heat shock proteins (HSPs) could be useful predictive markers in BCG responses.

METHODS

Thirty-three primary resected G3 superficial bladder tumours were included in the study. All patients received adjuvant BCG instillations. The mean follow-up was 56 mo (range: 24-132 mo). HSP expression was evaluated by immunochemistry.

RESULTS

In the 33 patients, 18 had no recurrence (group 1), 9 had recurrence with no muscular invasion (group 2), and 6 had an invasive recurrence (group 3). A significant correlation was found between lack of expression of HSP90 and BCG response: the mean HSP expression was 92.7%, 84.4%, and 26.7% for groups 1, 2 and 3 tumours, respectively (p<0.0001). For the 6 patients who did not positively respond to BCG, HSP expression was <40%. All the tumours with a HSP90 expression >40% positively responded to BCG, corresponding to group 1 or 2 patients. In contrast, HSP60 expression was not correlated to the BCG response.

CONCLUSIONS

HSP90 could be considered as a very promising marker to assess BCG treatment response. Low HSP90 expression (<40%) could be useful to predict BCG failure and early stage cystectomy could be proposed for these selected patients with primary high-risk grade 3 superficial bladder tumours.

Heat shock proteins HSP27, HSP60, HSP70, and HSP90: expression in bladder carcinoma

BACKGROUND

Heat shock proteins (HSPs) are synthesized by cells in response to various stress conditions, including carcinogenesis. The expression of HSPs in neoplasia has been implicated in the regulation of apoptosis, and HSPs also can act by increasing immunity. In the current study, the authors attempted to clarify the significance of HSPs in bladder carcinoma and their effect on tumor behavior.

METHODS

Expression levels of the 27-kilodalton HSP (HSP27), HSP60, HSP70, and HSP90 were studied using immunohistochemistry on tissue sections from 42 transitional cell carcinomas of the bladder (14 Grade 1 tumors; 13 Grade 2 tumors; 15 Grade 3 tumors, including 3 tumors associated with carcinoma in situ; 30 Stage Ta tumors; 7 Stage T1 tumors; and 5 Stage T2 tumors). Bladder specimens from 10 healthy patients were used as controls in the study. The selected patients had a mean follow-up of 52 months (range, 24-78 months). Among the 37 patients with superficial bladder carcinoma, 17 patients did not have any recurrence after undergoing primary resection, and 20 patients developed recurrent disease, including 4 recurrences with muscle invasion. HSP expression was evaluated according to the percentage of positively stained cells, and loss of expression was defined as < 80% of stained cells.

RESULTS

In normal bladder specimens, all four HSPs (HSP27, HSP60, HSP70, and HSP90) were expressed strongly in the cytoplasm and membrane from the basal cell layer to the superficial cell layer. Loss of expression was detected in tumors: respectively, 45.2%, 38.1%, 69.0% and 23.8% of tumors showed a loss of immunostaining for HSP27, HSP60, HSP70, and HSP90. No correlation between HSP expression and grade was found. Low expression levels of HSP27 and HSP60 were correlated with higher tumor stage (87% vs. 6% [P < 0.001] and 78% vs. 9% [P < 0.01], respectively). HSP60 and HSP90 expression levels were correlated with final outcome for patients with superficial bladder carcinoma: loss of expression was associated with the risk of developing an infiltrating recurrence (97% vs. 6.0% [P < 0.001] and 88.2% vs. 52.5% [P = 0.02] for HSP60 and HSP90, respectively).

CONCLUSIONS

HSPs were expressed in normal urothelium, and the current results indicated that loss of HSP60 and HSP90 expression may have prognostic relevance in patients with bladder carcinoma. The authors believe that HSP60 may be a very useful marker for patients with superficial bladder carcinoma and may be used for predicting disease progression. If these data are confirmed, low HSP60 expression levels may be usable as a prognostic marker to identify patients for whom local treatment would be insufficient.

Heat shock proteins in the genitourinary system

Heat shock proteins are ubiquitous molecules that are expressed in all living organisms in response to stress. They have two specific roles: protection against cell damage and modulation of the immune response. Recent studies have dramatically increased our knowledge and understanding of the role of heat shock proteins in the genitourinary system. This review uses a Medline approach to examine the current literature.

Heat shock proteins: their role in urological tumors

PURPOSE

Heat shock proteins are ubiquitous molecules that are expressed in response to stress in all living organisms. The 3 important roles in regard to cancer development that have also been described are the regulation of apoptosis, modulation of the immune response and drug resistance.

MATERIALS AND METHODS

Recent studies have dramatically increased our current knowledge and understanding of the role of heat shock protein in cancer. We used a MEDLINE approach to examine the past and current literature.

RESULTS

The roles of heat shock protein in relation to urological tumors, namely those of the prostate, bladder, kidney and testis, are diverse. There are possible sites for heat shock protein modifications that may lead to new therapeutic approaches to urological cancer.

CONCLUSIONS

The possibility of treating patients with vaccines earlier in the disease course may stimulate research.

What are the immunologically active components of bacille Calmette-Guérin in therapy of superficial bladder cancer?

The subcomponents of bacille Calmette-Guérin (BCG) involved in the mechanism of action of intravesical BCG immunotherapy used for prophylaxis of superficial bladder cancer recurrences have been poorly investigated. We purified various BCG subcomponents and analyzed in vitro their ability to enhance a Th1 polarized immune response as well as to increase lymphocyte-mediated cytotoxicity against bladder tumors. Human peripheral blood mononuclear cells (PBMCs) from healthy purified protein derivative-positive subjects were incubated for 7 days with whole BCG and various fractions (BCG cell wall, plasma membrane, cytosol, purified polysaccharides as glucan or arabinomannan, purified native proteins from BCG culture filtrate, recombinant 22 kDa protein, phosphate transporter PstS-2 and -3 proteins). IFN-gamma, IL-12, IL-2, and IL-6 production by stimulated PBMCs was compared to unstimulated controls and the phenotype of expanded cells analyzed by flow cytometry (FACS analysis). A (51)Cr-release assay monitored the cytotoxicity of amplified effector cells against T24 bladder tumor cells. Live BCG and most of its subcomponents (with the exception of cytosol, PstS-2 and -3) significantly enhanced IFN-gamma and IL-12 secretion, expanded CD3(-)CD56(+) cells and the non-MHC-restricted cytotoxicity against bladder tumor cells compared to unstimulated controls (all P < 0.001, t-test). IL-2 receptor blockage resulted in a clear reduction in the cytotoxic activity of stimulated PBMCs. Numerous BCG subcomponents thus provide positive stimuli for Th1 cell differentiation and enhance in vitro, non-MHC-restricted cytotoxicity against bladder tumor cells. Our findings provide the basis for the therapeutic use of several of these subfractions in experimental animal models bearing bladder tumors.

Recent perspectives in topical therapy in superficial bladder cancer

With regard to side-effects in intravesical bacillus Calmette-Guérin instillation therapy and the limited efficacy of intravesical chemotherapy, there is still a need for improvement of these standard therapies. Recently, technical adjuvant means or the modification of cytostatic drugs have been undertaken to improve the efficacy of intravesical chemotherapy. Prognostic indicators of the response to bacillus Calmette-Guérin immunotherapy have been identified, but indicators of side-effects are needed in order to improve the benefit-to-risk ratio of bacillus Calmette-Guérin instillation therapy. Many innovative treatment options, however, still require a definition of their clinical value.