IGF1 and neoplasm: While these data support an immunostimulatory effect, human tumor-associated B cells can also have direct pro-tumorigenic and immunosuppressive activities, e.g., through the secretion of IGF-1, which can induce drug resistance in melanoma cells via FGFR3 activation, and by the suppression of tumor-specific T cell responses through the expression of PD-1, IL-10, or IL-35, as demonstrated in human hepatocellular carcinoma [8,9].