MMP9 and melanoma: Metastatic melanoma is characterized by high levels of matrix metalloproteinase (MMP)‐2 and ‐9 secretions that decompose the surrounding ECM, allowing melanoma cells to spread to other organs.[22] Therefore, to investigate the release level of MMPs by the printed spheroids, the amounts of MMP‐2 and MMP‐9 were analyzed through enzyme‐linked immunosorbent assay (ELISA).