Biologic characteristics of T1 papillary bladder cancer. Flow cytometric study of paraffin-embedded material

DNA ploidy, proliferative activity (evaluated in terms of the proliferative index [PI]) and epidermal growth factor receptors (EGF-R) expression in primary bladder cancer in 52 patients were studied by means of flow cytometry and immunohistochemistry. Forty of the 52 tumors yielded evaluable DNA histograms: 22 were diploid (55%) and 18 aneuploid (45%) (median DNA index = 1.5). Ninety-five percent of the tumors were positive for EGF-R expression. The median PI value of the entire case series, estimated with a mathematical model, was 5.4%, or 6.7% in diploid tumors and 12.1% in aneuploid ones. EGF-R expression was higher in aneuploid than diploid tumors. Most of the well-differentiated tumors were diploid, while aneuploid populations and positivity for EGF-R expression were more frequent in poorly and moderately differentiated tumors. No differences in proliferative activity were observed in relation to grade. Overexpression of EGF-R in aneuploid tumors and a relationship between it, proliferative activity and grading were observed. The disease-free survival rates were 72% and 91% for patients with aneuploid and diploid tumors, respectively.