Western blot analysis was used to assess cell membrane monocarboxylate transport and lactate dehydrogenase levels.

<p>Tissue hypoxia in the tumors was also assessed by HIF1-α expression. A) Western blots showed a decrease in MCT4 expression in MDA-MB-231 tumors radiation treated with radiation as compared to controls. The difference was significant (* P<0.03). B) A small decrease in MCT4 expression was observed in treated MDA-MB-231 cells <i>in vitro</i>. C) HIF1-α expression was higher for the treated tumors, but the difference was not significant. D) Expressions of lactate dehydrogenase isoforms B were significantly lower in treated tumors. E) Little changes were found for expressions of LDH-A and LDH-B in treated and control cells. GAPDH was used as a loading control.