MDA-MB-231 breast tumor cells were cultured for 24 hours (n ≥ 3) with titrating doses of DCA starting from 80 mM and diluted 2-fold to the lowest concentration of 2.5 mM. Percent viability for all groups of replicates was normalized by dividing absorbance (590 nm) values by the absorbance values obtained from sham treated (growth media) control cells. Cytotoxicity by DCA in a crystal violet assay was carried out under A) normoxia (O2 = 20%) and B) hypoxia (O2 = 1%). Asterisks (*) designate viable DCA treated cells percentage that were significantly different from 100% viable sham treated cells. Error bars are expressed as SEM.