Branched-chain amino acids to tyrosine ratio value as a potential prognostic factor for hepatocellular carcinoma

The prognosis of hepatocellular carcinoma (HCC) depends on tumor extension as well as hepatic function. Hepatic functional reserve is recognized as a factor affecting survival in the treatment of HCC; the Child-Pugh classification system is the most extensively used method for assessing hepatic functional reserve in patients with chronic liver disease, using serum albumin level to achieve accurate assessment of the status of protein metabolism. However, insufficient attention has been given to the status of amino acid (AA) metabolism in chronic liver disease and HCC. Fischer's ratio is the molar ratio of branched-chain AAs (BCAAs: leucine, valine, isoleucine) to aromatic AAs (phenylalanine, tyrosine) and is important for assessing liver metabolism, hepatic functional reserve and the severity of liver dysfunction. Although this ratio is difficult to determine in clinical situations, BCAAs/tyrosine molar concentration ratio (BTR) has been proposed as a simpler substitute. BTR correlates with various liver function examinations, including markers of hepatic fibrosis, hepatic blood flow and hepatocyte function, and can thus be considered as reflecting the degree of hepatic impairment. This manuscript examines the literature to clarify whether BTR can serve as a prognostic factor for treatment of HCC.