CD4 and neoplasm: Accordingly, tumor infiltration and intratumoral activation of CD4+ and CD8+ T cells in response to the mIL12 moiety correlated well with the intratumoral penetration of HCT-mono-mIL12 and the subsequent antitumor potency in the CT26-HER2/neu–TBM model, indicating that the greater tumor penetration of HCT-mono-mIL12 directly translates into the enhancement of therapeutic effects.