MRC1 and neoplasm: Increasing culture medium to pH > 8.5 led to decreased THP-1 cell viability (Fig. 4b, n = 6 independent experiments, p < 0.01 pH 9.5 versus all other pH levels tested) and an increased percentage of THP-1 cells staining positive for CD206 (tumor-associated macrophage marker) (Fig. 4c, n = 6 independent experiments, p < 0.0001 pH 8.5 versus pH 7.5 and pH 6.5) and CD80 (marker of M1 activation) (Fig. 4d, n = 6 independent experiments, p < 0.0001 pH 8.5 versus pH 7.5 and pH 6.5), albeit with a higher percentage of cells staining for CD206 than CD80 at pH 8.5 (Fig. 4c and d).