SLC38A1 and esophageal cancer: Although SLC38A1 or SLC38A2 glutamine transporters are also upregulated in tumors, which may functionally compensate the SLC1A5 deficiency, the solitary knockdown of SLC1A5 resulted in cell cycle arrest in the G0/G1 phase and the blockage of S phase entry, which is consistent with previous findings in esophageal cancer, gastric cancer, and ovarian cancer [3, 22, 23].