Cytochemical identification of quiescent and growth-activated tumor cells.

Cytochemical determinations of the amount of protein in the cell nucleus together with the amount of DNA give a background for judging the growth activity of the individual cell. A series of human breast carcinomas of different malignancy grades was studied, and it was shown that judged by their types of DNA profiles, the tumors of low malignancy grades were characterized by growth-arrested cells while the majority of cells in highly malignant tumors were intensely growth activated. This indicates that determinations of proteins in the nucleus together with DNA determinations can be used to better judge malignancy grades in individual breast carcinomas, which is of considerable clinical importance.