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The novel TRM staging system predicts survival of gastric cancer more accurately than the 7th edition TNM system. It may be considered as an alternative to TNM system.

The relationship between oxidation stress and phosphoinositide 3-kinase (PI3K) signaling in pancreatic ␤-cell dysfunction remains unclear. Mercury is a well-known toxic metal that induces oxidative stress. Submicromolar-concentration HgCl 2 or methylmercury triggered reactive oxygen species (ROS) production and decreased insulin secretion in ␤-cell-derived HIT-T15 cells and isolated mouse islets. Mercury increased PI3K activity and its downstream effector Akt phosphorylation. Antioxidant Nacetyl-L-cysteine (NAC) prevented mercury-induced insulin secretion inhibition and Akt phosphorylation but not increased PI3K activity. Inhibition of PI3K/Akt activity with PI3K inhibitor or by expressing the dominant-negative p85 or Akt prevented mercury-induced insulin secretion inhibition but not ROS production. These results indicate that both PI3K and ROS independently regulated Akt signaling-related, mercury-induced insulin secretion inhibition. We next observed that 2-or 4-week oral exposure to low-dose mercury to mice significantly caused the decrease in plasma insulin and displayed the elevation of blood glucose and plasma lipid peroxidation and glucose intolerance. Akt phosphorylation was shown in islets isolated from mercury-exposed mice. NAC effectively antagonized mercury-induced responses. Mercury-induced in vivo effects and increased blood mercury were reversed after mercury exposure was terminated. These results demonstrate that low-dose mercury-induced oxidative stress and PI3K activation cause Akt signaling-related pancreatic ␤-cell dysfunction.

As PD-1/PD-L1 immune checkpoint inhibitors exhibited promising clinical outcomes in various types of solid tumors, PD-1/PD-L1 blockades have been explored for the treatment of hepatocellular carcinoma (HCC). However, the association of PD-L1 with antitumor immunoregulation is not clearly defined in HCC. Here, we evaluated the characteristics of PD-L1 expression, CD8 T-cell infiltration and their relationship in HCC. A total of 411 resected tumor specimens from HCC patients were immunostained for PD-L1 and CD8. Only 78 (19%) cases showed ≥5% membranous PD-L1 expression on tumor cells, although a significantly positive correlation was found between PD-L1 expression and CD8 T-cell densities. Moreover, patients with higher tumor PD-L1 expression also showed a higher hepatitis B virus load, which was also related to increased CD8 infiltration. Survival analysis suggested that both tumor and stroma PD-L1 status did not significantly affect overall survival or recurrence-free survival in patients. Although high CD8 T-cell density was overall associated with better overall survival and recurrence-free survival, its favorable prognostic value was eliminated by high tumor PD-L1 expression. Further flow cytometric and enzyme-linked immunosorbent assay (ELISA) results from the coculture of HCC cell lines with specific CD8 cytotoxic T lymphocytes (CTLs) demonstrated that CD8 CTLs remarkably upregulated PD-L1 expression on tumor cell lines by HLA class-I specificity, and the overexpression of tumor PD-L1 impaired interferon-γ secretion by CD8 CTLs in a negative feedback regulation mechanism. In conclusion, our findings reveal an interaction between PD-L1 expression and CD8 T-cell immunity in HCC, although PD-L1 is not a prognostic factor for the patients.

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