A COMPARISON OF DIFFERENT METHODS TO DETERMINE CELL-PROLIFERATION BY FLOW-CYTOMETRY

The proliferation of human melanoma cells (MeWo) in vitro was studied with a number of different techniques. In particular, we compared the expression of PCNA and the Ki-67 antigen on the one hand with BrdU pul se and continuous labelling on the other. Two-dimensional flow cytomet ry (with DNA content as a second parameter) was employed to discrimina te between cycling and non-cycling cells as well as cells in the G(1), S and G(2) phases of the cycle. Cell cultures in different stages of growth were analyzed. We found that the percentage of anti-PCNA and Ki -67 positive cells agreed very well with the BrdU pulse and continuous labelling index, respectively. Our data further support the assumptio n that under certain conditions PCNA is a marker of S-phase cells, whe reas Ki-67 can be used to quantify the growth fraction. Possible pitfa lls of the techniques are discussed.