ECCM inhibits spontaneous in vitro B-CLL cell apoptosis.

Purified tumoral cells were cultured either with CM or ECCM derived from fresh HUVEC (A) or ECV-304 cells (B). After 1 (▩), 2 (▨), or 3 (░) days of culture, B-CLL cells were removed from the well by pipetting and were stained with annexin-V–FITC and PI for flow cytometry analysis. Conditioned medium from HUVEC or ECV-304 cells was collected after 7 and 3 days of culture, respectively. Results are expressed as the mean ± SEM of 5 independent experiments and represent the percentage of apoptotic cells.