In experimental autoimmune encephalomyelitis (EAE), inhibition of Th17 cells following calcitriol treatment has been reported in young mice.19 Additionally, calcitriol has been shown to inhibit Th17 cell generation in vitro.44 However, in our study, CD3+CD4+ splenocytes from young 4T1 tumor-bearing mice treated with tacalcitol (or both compounds) exhibited increased Rorc, Tbx21, and Spp1 mRNA expression. Here, CD4 is linked to neoplasm.