Role of glutamine synthetase as a surrogate marker in predicting β‐catenin mutated hepatoceullar carcinoma

Wnt/β‐catenin signaling is indispensible in cell growth and proliferation, but plays a role in development of hepatocellular carcinoma (HCC) when mutation occurs and the pathway becomes aberrantly activated. Nuclear/cytoplasmic (N/C) staining of β‐catenin significantly correlates with mutation of β‐catenin, and positive staining of glutamine synthetase (GS) is also suggested as a surrogate marker of β‐catenin mutation. In this study, we aimed to elucidate the relation between N/C staining of β‐catenin and GS staining in a large number of samples from a tissue array. Immunohistochemical staining for β‐catenin and GS was performed on slides of HCC tissue array, LV2082 by Biomax©, which included 94 samples in duplicate. In β‐catenin staining, 68 (72.3%) were positive for N/C pattern, 15 (16.0%) for membranous pattern, and 10 (10.6%) were negative. In GS staining, 30 (31.9%) were positive. Out of 30 GS positive cases, 27 (90.0%) showed positivity for N/C staining of β‐catenin. GS positive tissues had a high probability of having N/C staining of β‐catenin, and therefore GS staining could be potentially used as a surrogate marker for predicting β‐catenin mutated tumors.