In support of our last assumption, Yaddanapudi et al (5) most recently reported that the suicide inhibitor of MIF, 4-IPP, significantly slowed the rate of B16 tumor growth, but to intracellularly block MIF secretion by TAMs, 4-IPP was given at doses 10-fold higher (80 mg/kg) than ISO-66 in our models, raising specificity (35) and toxicity issues, if such high concentrations were to be adapted for clinical use. Here, MIF is linked to neoplasm.