“Using the fluorescent Ca2+ indicator fura-2 it is further shown that both drug-resistant daunorubicin (EHR2/DNR+) and vincristine (EHR/VCR+) sublines had lower (50-80 nM) concentration of cytosolic free calcium ([Ca2+]i) compared to their corresponding wild-type parenteral tumors (140-180 nM).”