In ASS1-high tumor cells, such as prostate cancer (Gannon et al., 2010), breast cancer (Cavdar et al., 2003) and renal cell carcinoma (Tate et al., 2008), the presence of arginase in the TME can cause adverse effects, especially regarding the immune response to cancer cells. The gene discussed is ASS1; the disease is hereditary clear cell renal cell carcinoma.