It has been discovered that disrupting the stromal capsule restores a better vasculature/tumor perfusion and improve T cells infiltration inside the core of a melanoma. The invention relates to the use of drugs or immunoconjugates that target the transmembrane protease ADAM12 and deplete the cells that express it. Since ADAM12 protein is specifically expressed by stromal cells of the tumor stromal capsule and around vessels in models for prostate cancer, neuroendocrine pancreatic cancer and melanoma, an ADAM12 inhibitor is useful in anti-tumor therapies as an adjuvant. The invention encompasses methods, compositions, and kits containing ADAM12 inhibitors for use in the depletion of ADAM12+ stromal cells in cancer patient, particularly together with anti-tumor compounds and treatments.