Starvation in cancer cells: circulating arginine is good for cancer but bad for patients.

Introduction: Currently, basic understanding of heterogeneity and complexity of tumors is depicted at molecular, cellular, genetic, epigenetic and metabolic adaptations levels. Areas covered: There are appreciable numbers of views to pinpoint signaling axis that support metabolic adaptations of cancer cells in response to environmental pressures including nutritional factors and drug treatments. Specifically, nutritional deprivation and autophagy in certain types of cancer are linked to the abilities of cancer cells to use arginine in an auxotrophic or prototrophic manner. Expert opinion: Hence, this paper highlights the current scope of arginine- and autophagy-centered metabolic adaptations across tumor types and possible avenues to bring tumors towards cytotoxic or cytostatic death.