ERBB2 and neoplasm: To elucidate the anti-HER2 binding kinetics-dependent antitumor activity of HCT-mono-mIL12, we next determined the paracellular penetration and spread within tumor tissues by IF staining for tumors excised from HCT-mono-mIL12-treated CT26-HER2/neu–TBM at 3 h and 6 h after the second dosing (Figure 4A).