NUCLEAR MORPHOMETRY AND DNA CONTENT IN GRADING OF RENAL CELL CARCINOMA

Abstract

Using nuclear morphometry, the author tried to objectify histological grading by nuclear atypia of renal cell carcinoma, and simultaneously examined its relationship with nuclear DNA ploidy. The subjects were 35 preoperatively untreated cases of renal cell carcinoma. The region of the highest histological grade was selected from H-E stained specimen, manually measured for 300 nuclei under 1, 000 times of oil immersion by means of graphic digitizer, and measured for mean nuclear area and correct nuclear roundness factor (NRF). From the paraffin-embedded tissue just below the measured area, nuclear DNA ploidy pattern was analyzed by cytofluorometry.
The relation of histological grading with mean nuclear area and correct NRF was: 30.8±7.7μm² and 32.0±10.1 for 12 cases of the group grade 1, 36.4±5.6 μm² and 37.7±12.8 for 16 cases of the group grade 2 and 48.3±9.8μm² and 71.1±24.1 (mean±SD) for 7 cases of the group grade 3.The both parameters showed significant differences between the group grade 3 and the group grade 1 or the group grade 2. As for the prognosis, cancer death was frequent for the group of mean nuclear area≥37.3μm² or the group of correct NRF≥45.7; an obvious significant difference (p<0.01) in the survival curves was seen between their respective low-value groups, indicating that prognosis could be made more correctly than histological grading. Incidence of abnormal nuclear DNA ploidy pattern increased with a rise of histological grade, and both mean nuclear area and correct NRF showed similar behaviors.
In the examination of histopathological specimens of renal cell carcinoma, the measurement of mean nuclear area and correct NRF was regarded as providing with an objective index of histological grading corresponding to biological malignancy.