Consistent with this, increased expression levels of SLC7A5 have been observed in various types of cancer such as breast cancer [45], KRAS-mutated CRC [46], gastric cancer [47], lung cancer [48], pancreatic cancer [49], prostate cancer [50], melanoma [51], ovarian cancer [52] and hepatocellular carcinomas [53], and esophageal cancer [54]. This evidence concerns the gene KRAS and esophageal cancer.