Intranuclear localization of proliferating cell nuclear antigen during thecell cycle in renal cell carcinoma

OBJECTIVE: To investigate, with laser scanning cytometry (LSC), proliferati ng cell nuclear antigen (PCNA) expression during the cell cycle in renal ce ll carcinoma. STUDY DESIGN: DNA ploidy and intracellular localization of PCNA in renal ce ll carcinoma were determined using LSC and immunohistochemistry. The subjec ts were nine patients who had received surgery for renal cell carcinoma. Af ter DNA ploidy analysis, the glass slides were restained by immunohistochem istry of PCNA. LSC allowed direct observation of PCNA localization during t he cell cycle because we could obtain immunohistochemical staining of PCNA as a function of cell cycle phase for individual cells. RESULTS: PCNA was not demonstrated in the nuclei of G0/G1 cells. PCNA expre ssion increased from the S phase of the cell cycle. PCNA rapidly degraded a t the end of the G2 phase. In the late G2 and M phase, PCNA was not detecte d in almost any nucleus. CONCLUSION: LSC allows morphologic observation of the intracellular distrib ution of PCNA during the cell cycle in renal cell carcinoma.