Comparative histopathology and deoxyribonucleic acid flow cytometry of random mucosal biopsies in untreated bladder carcinoma.

In a study of 290 patients with untreated carcinoma of the bladder, histopathological studies of random mucosal biopsies were compared with the results of deoxyribonucleic acid (DNA) flow cytometry. By histopathology the findings were classified as severe atypia corresponding to primary grade 3 carcinoma in situ, atypia not fulfilling the criteria for carcinoma in situ and no atypia. The DNA histograms were classified as diploid or aneuploid. Aneuploid cell populations in mucosal biopsies were found mainly in cases with aneuploid tumors of grade 3. Of the biopsies classified as concomitant carcinoma in situ 76% were aneuploid. In biopsies exhibiting less severe or no atypia aneuploidy was found in 41 and 10%, respectively. For these 3 morphological categories the distributions of the aneuploid cell populations were similar irrespective of the histopathological findings and they were also the same as that found in primary carcinoma in situ. We concluded that gross chromosomal aberrations may appear at an early stage of the tumor development and before changes recognizable by morphology. The similarity of the DNA profiles of the aneuploid cell populations, regardless of morphological findings, indicates that apart from gross chromosomal aberrations changes of the phenotype are necessary for the expression of morphological changes.