Purpose:The programmed death-1ligand/programmed death-1 (PD-L/PD-1) pathway has been recently suggested to play a pivotal role in the immune evasion of tumors from host immune system. In this study, we tried to reveal the clinical importance and therapeutic potential of the PD-L/ PD-1pathway in pancreatic cancer, which is one of the most aggressive and intractable malignant tumors. Experimental Design: We used immunohistochemistry to investigate PD-L expression in 51 patients with pancreatic cancer who underwent surgery and explored the therapeutic efficacy of blocking the PD-L1/PD-1pathway in murine pancreatic cancer in vivo. Results: PD-L1^positive patients had a significantly poorer prognosis than the PD-L1^negative patients, whereas there was no significant correlation of tumor PD-L2 expression with patient survival. PD-L1 expression was inversely correlated with tumor-infiltrating T lymphocytes, particularly CD8 + T cells. These clinical data have suggested that the PD-L1/PD-1 pathway may be a critical regulator in human pancreatic cancer. Monoclonal antibodies against PD-L1 or PD-1 induced a substantial antitumor effect on murine pancreatic cancer in vivo. PD-L1 blockade promoted CD8 + T-cell infiltration into the tumor and induced local immune activation. Furthermore, the combination of anti^PD-L1 monoclonal antibody and gemcitabine exhibited a significant synergistic effect on murine pancreatic cancer and resulted in complete response without overt toxicity. Conclusion: Our data suggest for the first time that PD-L1 status may be a new predictor of prognosis for patients with pancreatic cancer and provide the rationale for developing a novel therapy of targeting the PD-L/PD-1pathway against this fatal disease.

Purpose: The aberrant expression of programmed cell death 1ligands 1and 2 (PD-Ls) on tumor cells dampens antitumor immunity, resulting in tumor immune evasion. In this study, we investigated the expression of PD-Ls in human hepatocellular carcinoma (HCC) to define their prognostic significance after curative surgery. Experimental Design: Immunohistochemistry was used to investigate PD-Ls expression as well as granzyme B + cytotoxic and FoxP3 + regulatory T cell infiltration on tissue microarrays containing 240 randomly selected HCC patients who underwent surgery. The results were further verified in an independent cohort of 125 HCC patients. PD-Ls expression on HCC cell lines was detected by Western blot assay. Results: Patients with higher expression of PD-L1 had a significantly poorer prognosis than patients with lower expression. Although patients with higher expression of PD-L2 also had a poorer survival, the difference in recurrence was not statistically significant. Multivariate analysis identified tumor expression of PD-L1 as an independent predictor for postoperative recurrence. No correlation was found between PD-Ls expression and granzyme B + lymphocyte infiltration, whereas a significant positive correlation was detected between PD-Ls expression and FoxP3 + lymphocyte infiltration. In addition, tumor-infiltrating cytotoxic and regulatory T cells were also independent prognosticators for both survival and recurrence. The prognostic value of PD-L1 expression was validated in the independent data set. Conclusion: Our data suggest for the first time that PD-L1 status may be a new predictor of recurrence for HCC patients and provide the rationale for developing a novel therapy of targeting the PD-L1/PD-1pathway against this fatal malignancy.

Purpose:The negative regulatory programmed death-1/programmed death-1ligand (PD-1/PD-L) pathway inT-cell activation has been suggested to play an important role in tumor evasion from host immunity. In this study, we investigated the expression of PD-L1 and PD-L2 in human esophageal cancer to define their clinical significance in patients'prognosis after surgery. Experimental Design: PD-L1 and PD-L2 gene expression was evaluated in 41esophagectomy patients by real-time quantitative PCR. The protein expression was also evaluated with newly generated monoclonal antibodies that recognize human PD-L1 (MIH1) and PD-L2 (MIH18). Results: The protein and the mRNA levels of determination by immunohistochemistry and realtime quantitative PCR were closely correlated. PD-L^positive patients had a significantly poorer prognosis than the negative patients. This was more pronounced in the advanced stage of tumor than in the early stage. Furthermore, multivariate analysis indicated that PD-L status was an independent prognostic factor. Although there was no significant correlation between PD-L1 expression and tumor-infiltrating T lymphocytes, PD-L2 expression was inversely correlated with tumor-infiltrating CD8 + Tcells. Conclusions:Thesedatasuggest thatPD-L1andPD-L2statusmaybeanewpredictorofprognosis for patients with esophageal cancer and provide the rationale for developing novel immunotherapy of targeting PD-1/PD-L pathway.

Hepatic tissue engineering using primary hepatocytes has been considered a valuable new therapeutic modality for several classes of liver diseases. Recent progress in the development of clinically feasible liver tissue engineering approaches, however, has been hampered mainly by insufficient cell-to-cell contact of the engrafted hepatocytes. We developed a method to engineer a uniformly continuous sheet of hepatic tissue using isolated primary hepatocytes cultured on temperature-responsive surfaces. Sheets of hepatic tissue transplanted into the subcutaneous space resulted in efficient engraftment to the surrounding cells, with the formation of two-dimensional hepatic tissues that stably persisted for longer than 200 d. The engineered hepatic tissues also showed several characteristics of liver-specific functionality. Additionally, when the hepatic tissue sheets were layered in vivo, three-dimensional miniature liver systems having persistent survivability could be also engineered. This technology for liver tissue engineering is simple, minimally invasive and free of potentially immunogenic biodegradable scaffolds.

The PNI is a simple and useful marker for predicting the long-term outcomes of gastric cancer patients independent of the tumor stage. Based on our results, we suggest that the PNI should be included in the routine assessment of gastric cancer patients.