HHLA2 and lactic acidosis: To mimic aspects of the tumor microenvironment, A498 and 786-O were cultured with hypoxia induction by CoCl2, or cultured under lactic acidosis or in glucose-free media in which glucose was replaced by galactose, but these conditions, alone or in combination with cytokines, did not induce HHLA2 (Table 2).