CD4 and ovarian cancer: In our studies, OTUB1‐isoform2 exerts oncogenic functions in gastric27 and ovarian cancers which is consistent with its isoform OTUB1.25, 29 The possible reasons for this are as follows: in the immune system, OTUB1‐isoform2 might function by encoding protein ARF‐1 to balance the functions of OTUB1 in normal T cells, thus regulating the CD4 T cell anergy.