DNA and nuclear protein measurement in columnar epithelial cells of human endometrium

Propidium iodide DNA flow cytometry, Feulgen-DNA, and nuclear light green protein scanning cytometry were performed in columnar epithelial cells of normal, nonmalignant human endometrium and endometrial adenocarcinomas. Columnar cells were identified by immunohistochemical staining for cytokeratin 18, an intermediate filament protein specifically present in columnar cell epithelium. DNA measurements derived from flow and scanning cytometry showed comparable results. The DNA content of the G0/G1 fraction of the adenocarcinomas had a considerable overlap with that of normal endometrium, with that of the carcinomas shifted toward higher values. For the carcinomas, no correlation was found with the histological grade, with the exception of the adenosquamous carcinomas. Most of the clinical stage I tumors showed a DNA content in the normal diploid region. Three of the four carcinomas of clinical stage II and higher had an increased DNA content. For the carcinomas, the percentage of cells in the proliferative fraction, as determined from scanning cytometric derived DNA histograms, was comparable to that of normal endometrium, or higher. No correlation was found with the histological grade. Tumors of clinical stage II and higher had intermediate values compared to carcinomas of lower stages. The nuclear protein/DNA ratio of malignant endometrium completely overlapped that of normal endometrium. Within the tumor population, no correlation was found with the histological grade, with the exception of the adenosquamous carcinomas, and clinical stage. Based on the aforementioned parameters, no discrimination could be obtained between normal and malignant endometrium. However, when the DNA content of the G0/G1 fraction was combined with the coefficient of variation of the nuclear protein/DNA ratio, a clear discrimination could be obtained with only two false-positive cases.