ARG1 and neoplasm: In our experiments, the transition of monocytic cells to the pro-tumor phenotype, denoted by increased F4/80 and arginase-1 expression, occurred more efficiently when the monocytes were incubated with A549 and DLD1 cells with downregulated Hsp70 (i.e., when the eHsp70 content in the extracellular space was lower; Figure 3).