VPS39 and neoplasm: To prove that increased Vam6 led to impaired iNKT cell functions in tumors, we generated B16F10 tumor-bearing Jα18-/- chimeric mice, in which we found that those intratumoral iNKT cells with reduced Vam6 expression produced more IFN-γ and IL-4 in response to α-GC injection, despite their normal granzyme B production (Figures 1J, K).