Cellular heterogeneity of the CR4 tumor cells.

(A) Initially dominating population of the densely packed elongated fibroblast-like cells. (B) Sparser elongated tumor cells with processes. (C) Appearance of small clusters of very small cells (∼7 µm) adjacent to fibroblast-like cells. (D) Typical holoclone induced by small CR4 cells. (E) Giant multinucleated cell within CR4 holoclone of small cells. (F) Colony of multinucleated cells.