KRAS and pancreatic neoplasm: Interestingly, glutamate has been implicated in increasing pancreatic cancer cells migration and invasion through binding to specific receptors and activating Kras-MAPK signaling.45 Tyrosine increase in the feces from PC patients without metastasis was consistent with the functional prediction performed on gut microbiota, in which phenylalanine, tyrosine and tryptophan biosynthesis resulted increased as well.