ARG2 and cancer: Previous research reported that the high expression of ARG2 was related to immunosuppressive microenvironments (45, 46); The high expression of MMPs was associated with N2 tumor-associated neutrophils (47); and the overexpression of S100A4 would promote the metastasis, invasion, and angiogenesis of cancer cells, which are related to poor prognosis in patients with cancer (48–50).