Apoptosis in bladder carcinomas detected with monoclonal antibody to single-stranded DNA: relation to cell cycle regulators and survival.

OBJECTIVES: To investigate the incidence of baseline apoptosis in relation to p27(Kip1), p53, and p21(Cip1) expression, proliferation status, standard clinicopathologic parameters, and patient outcome. Cell cycle regulators and apoptotic cell death have been implicated in tumor aggressiveness in many human malignancies. Their interaction, however, in the prognosis of patients with transitional cell carcinoma (TCC) of the urinary bladder has not yet received intense scrutiny. METHODS: Apoptotic fractions were quantified immunohistochemically by means of a novel monoclonal antibody recognizing single-stranded DNA regions in apoptotic nuclei in 103 paraffin-embedded primary TCC specimens. Proliferative activity was expressed as the percentage of Ki-67 positive cells (Ki-67 index). Tissue specimens were also stained for p27(Kip1), p53, and p21(Cip1) proteins. Patients were followed up until death (n = 30) or for an average of 40 months (median 36). RESULTS: The apoptotic index increased with grade, T stage, nonpapillary status, proliferative activity, and p53 expression and was inversely related to p27(Kip1) and independently to p21(Cip1) expression. A negative correlation was found between p27(Kip1) expression and proliferation. The increased apoptotic index had an adverse impact on overall and disease-free survival (univariate analysis) and, along with T stage, was an independent predictor in muscle-invasive TCC. CONCLUSIONS: An increased apoptotic rate, increased proliferative activity, and decreased p21(Cip1) expression are independently interrelated in TCC. More importantly, the assessment of apoptotic potential appears to be more informative than standard prognosticators in predicting overall survival in patients with muscle-invasive TCC.

A comparative assessment of proliferating cell nuclear antigen, c-myc p62, and nucleolar organizer region staining in non-Hodgkin's lymphomas: a histochemical and immunohistochemical study of 200 cases.

Proliferating cell nuclear antigen (PCNA) and c-myc p62 oncoprotein are two nuclear proteins expressed in proliferating and transformed cells. They can be recognized immunohistochemically in paraffin sections by the monoclonal antibodies PC-10 and c-myc 1-9E10, respectively. On the other hand, nucleolar organizer regions (NORs) are loops of DNA that carry the r-RNA genes and can be visualized in paraffin sections as black dots (AgNORs) using a silver impregnation method. It has been suggested that the mean number of AgNORs may reflect the cellular kinetics of a tumor. We independently examined 200 cases of non-Hodgkin's lymphomas using the monoclonal antibodies PC-10 and c-myc 1-9E10, as well as the AgNOR method. Our study shows a very significant correlation between PCNA, c-myc expression, and AgNOR count on the one hand and histologic grade on the other (P < .001), although a significant overlap among the three grades exists. PC-10, c-myc 1-9E10, and AgNOR scores are all shown to be linearly related, even though significant discrepancies were observed, and the correlation is stronger between PCNA and AgNORs (PCNA v c-myc p62, r = .551; PCNA v AgNORs, r = .746; c-myc p62 v AgNORs, r = .529; P < .001). A remarkable finding is that the intermediate group of lymphomas is heterogeneous as far as the proliferative rate is concerned: diffuse large cell cleaved/non-cleaved lymphomas (category G of the Working Formulation) are characterized by a significantly higher proliferative index, as evidenced by the elevated PCNA, c-myc p62, and AgNOR scores, in comparison with the other types of intermediate-grade lymphomas (P < .001). However, the proliferative rate is lower than that of the high-grade lymphomas (PCNA, P < .05; c-myc p62, P < .001; AgNORs, P < .005). No significant difference exists between B-cell and T-cell lymphomas except for the higher expression of c-myc p62 in intermediate-grade B-cell lymphomas, obviously due to the higher proliferative rate of diffuse large cell lymphomas. Based on our findings, it appears that the combination of PCNA, c-myc p62, and AgNORs provides an accurate estimate of the proliferative rate of non-Hodgkin's lymphomas in paraffin sections. Clinical studies may show whether this information has prognostic value independent of histologic classification. In addition, our results suggest that category G (diffuse large cell) lymphomas may belong to a malignancy grade higher than the intermediate grade, a suggestion consistent with their more aggressive biologic behavior.