Intravesical bacillus calmette-guerin (BCG) as inducer of tumor-suppressing proteins p53 and p21 Waf1-Cip1 during treatment of superficial bladder cancer.

PURPOSE: Previous in vitro investigations recorded an inhibition of cell proliferation by BCG when added to different cell cultures. The induction of apoptosis by BCG is controversial. Our study aimed to evaluate the influence of BCG on the expression of tumor suppressing proteins p53 and p21Waf1-Cip1 and apoptosis of the urothelial cells in vivo. MATERIALS AND METHODS: Twenty-one cases of superficial bladder cancer, treated with TUR and subsequent intravesical BCG, were studied retrospectively. The assays evaluated the expression of p53 and p21Waf1-Cip1 by immunochemistry (IHC), and the presence of apoptosis by TUNEL assay. The estimates were performed, in each case, on the following specimens: one tumor sample and one non-neoplastic sample collected during the TUR which preceded the administration of BCG; one non-neoplastic sample collected 3 months after the diagnosis; and one non-neoplastic sample collected in the first 2 weeks after the completion of the treatment. Samples of 6 cancer recurrences detected during BCG were examined too. RESULTS: As usual for non-neoplastic urothelium, the pre-BCG samples displayed poor p53 and p21Waf1-Cip1 immunoreactivity. By contrast, the samples collected during and in the aftermath of BCG showed an overall increase of the expression of both proteins. The rare occurrence of apoptosis proved to be chronologically unrelated to the BCG treatment. DISCUSSION: The relationship between changes of the IHC features and BCG suggests that BCG, at least under some circumstances, can induce the activation of wild type p53 and p21Waf1-Cip1 in the urothelium. The mechanism of the BCG-p53 status interaction and its role in the antitumor activity of BCG remain to be clarified.

Molecular biology in uro-oncology: clinical application. Prognostic factors in bladder cancer.

In the bladder cancer the most important prognostic factors are the stage, the grade, the presence or absence of lymph nodal metastasis, the response to therapy with B. C. G. etc.... In any case, even in the context of the same clinical stage, it is not possible to correctly evaluate the evolution of the disease. The Author did a literature revision and got a personal contribution about the effective utility of same biological prognostic factors. In a study about superficial bladder tumor using monoclonal antibody MIB-1 (Ki-67) a correlation between proliferation index (P.I.) and grade was noted. In particular the presence of a P.I. above 40% correlated with greater precocity and frequency of recurrences. A similar study showed that the expression of protein p21 correlated with a greater precociousness and with recurrence frequency. In conclusion, we have also carried out an evaluative study on the expression of oncosuppressor gene p53. In superficial bladder cancer this study showed up a correlation between the expression of protein p53 and a greater precociousness and frequency of recurrences.

Evaluation of c-ras oncogene product (p21) in superficial bladder cancer.

OBJECTIVES: The aim of our study is the evaluation of the prognostic importance of p21 protein in superficial bladder cancer. METHODS: One hundred and fourteen patients with an initial diagnosis of monofocal bladder cancer (stage Ta-T1) following TUR were investigated. On the tissue removed by TUR, besides the usual pathological evaluation, an immuno-histochemical investigation was carried out in order to ascertain the presence of c-ras oncogene product (protein p21). The actuarial curves concerning the time free from the first recurrence were computed, comparing different subgroups in regard to protein p21 presence, grade and stage of the tumour. RESULTS: The analysis of the results shows the importance of tumour stage as a predictor of recurrence, as well as that of the presence of c-ras products. This last factor increases the risk of recurrence almost 2-fold, in the same time lag, for c-ras-positive patients (p < 0.001). The prognostic significance of c-ras is independent of stage. CONCLUSION: Our data underline the possibility of acquiring important information on the prognosis of superficial bladder cancer patients, pointing out the significance of c-ras oncogene product.