title: Tyrosine, phenylalanine, and tryptophan in gastroesophageal malignancy: a systematic review.
abstract: Gastroesophageal cancer has a rapidly increasing incidence worldwide and reliable biomarkers are urgently required to facilitate earlier diagnosis and improve survival. The aromatic amino acids tyrosine, phenylalanine, and tryptophan represent potential biomarkers and their relation to gastroesophageal cancer will be evaluated in this review. An electronic literature search was performed to identify all published research relating to the measurement of tyrosine, phenylalanine, or tryptophan in the biofluids or tissues of patients with gastroesophageal cancer. Sixteen studies were included in this systematic review. Six studies investigated serum concentrations, which all found decreased concentrations of these aromatic amino acids, except one study that found increased phenylalanine. Five studies reported increased concentrations within gastric content of these patients and two reported increased urinary concentrations. Tissue concentrations of these aromatic amino acids were increased in three studies. Tyrosine, phenylalanine, and tryptophan represent potential biomarkers of gastroesophageal cancer, and further research is necessary to definitively establish the mechanism responsible for altered concentrations of these compounds in patients with gastroesophageal cancer.
authors.affiliation: Department of Surgery and Cancer, Imperial College London, St. Mary's Hospital, London, United Kingdom.
authors.forename: Tom
authors.initials: T
authors.lastname: Wiggins
authors.affiliation: Department of Surgery and Cancer, Imperial College London, St. Mary's Hospital, London, United Kingdom.
authors.forename: Sacheen
authors.initials: S
authors.lastname: Kumar
authors.affiliation: Department of Surgery and Cancer, Imperial College London, St. Mary's Hospital, London, United Kingdom.
authors.forename: Sheraz R
authors.initials: SR
authors.lastname: Markar
authors.affiliation: Department of Surgery and Cancer, Imperial College London, St. Mary's Hospital, London, United Kingdom.
authors.forename: Stefan
authors.initials: S
authors.lastname: Antonowicz
authors.affiliation: Department of Surgery and Cancer, Imperial College London, St. Mary's Hospital, London, United Kingdom. g.hanna@imperial.ac.uk.
authors.forename: George B
authors.initials: GB
authors.lastname: Hanna
mesh_terms: D004938:Esophageal Neoplasms / Q000175:diagnosis*; D006801:Humans; D010649:Phenylalanine / Q000378:metabolism*; D013274:Stomach Neoplasms / Q000175:diagnosis*; D014364:Tryptophan / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism*
chemical_list: D014443:Tyrosine; D010649:Phenylalanine; D014364:Tryptophan