A thermosensitive hydrogel based on PLGA-PEG-PLGA was employed for the peritumoral injection in human epidermal growth factor receptor 2 (HER2)-positive BT474 tumor-bearing mice, facilitating a prolonged release of trastuzumab and collagenase over two to three weeks due to the gradual breakdown of the polyester components.561 The co-delivery of collagenase notably diminished the collagen density within the solid tumor ECM, enhancing the deep tissue penetration of antibodies and thereby amplifying both the interstitial transport and the overall anti-tumor effectiveness of the therapy. This evidence concerns the gene ERBB2 and neoplasm.