FCGRT and neoplasm: The pH dependence of the albumin-FcRn interaction (binding at pH 6.0 with no detectable interaction at near neutral pH [8]), combined with the observation that the tumor microenvironment can be acidic (pH 6.5-6.9 [20]), prompted us to also investigate the effect of pH (pH 6.5-7.5) on albumin accumulation in HCC1419 and DU145 cells (Figure 3A, 3B).