ATG5 and neoplasm: To establish a relevant in vitro approach to study the effects of CR and/or autophagy inhibition in Atg5−/− and Atg5+/+ cells, we first characterized the impact of CR on the serum metabolomic profile using an untargeted MRS-based metabolomics approach was evaluated in serum samples obtained 4 weeks after mice were transplanted with Atg5+/+ tumor cells.