RNH1 and malignant colon neoplasm: A cytometric analysis of RKO human colon cancer cells treated withmyxothiazol, an inhibitor of MRC complex III, and stained with FITC -Annexin Vand propidium iodide (PrI) revealed a significant population of apoptotic cells(Fig. 1).In general, three cell populations were observed:normal cells (Annexin V-negative, PrI-negative), apoptotic cells (AnnexinV-positive, PrInegative, approximately 20% of all cells), and a third smallpopulation of dead cells (Annexin V-positive, PrI-positive, whose fraction wasapproximately 3%).