ARG1 and neoplasm: In comparison to STAT1-WT-expressing cells from normal spleens, isolated tumor cells stimulated with either IFNγ, LPS, or the combination of both showed a shift towards upregulation of STAT3-activated genes, such as Arg1, Ccl2, and Cdh1. In contrast to the WT protein, mutant STAT1-∆N failed to accumulate in the nucleus upon cytokine stimulation.