Inhibition of MAP3K11, a kinase that facilitates signaling through JNK1 and IkappaB kinase in cancer (Slattery et al., 2012; Knackmuss et al., 2016), inhibited stimulation-induced CD4+ T cell proliferation in the 100 nM range, as did 25-hydroxycholesterol, a ligand of the G-protein-coupled receptor GPR183 that was implicated by both chromatin- and eQTL-based approaches. Here, MAP3K11 is linked to cancer.