Glucose transporters 1, 3, 6, and 10 are expressed in gastric cancer and glucose transporter 3 is associated with UICC stage and survival.

BACKGROUND: Due to proliferation and increased metabolism, cancer cells have high glucose requirements. The glucose uptake of cells is influenced by a group of membrane proteins denoted the glucose transporter family (Glut-1 to -12). Whereas increased expression and a negative correlation with survival have been described for Glut-1 in several types of cancer, the impact of other glucose transporters on tumor biology is widely unknown. METHODS: In this retrospective study, gastric cancer specimens of 150 patients who underwent total gastrectomy between 2005 and 2010 were stained for Glut-1, -3, -6, and -10 by immunohistochemistry. Expression of Glut-1, -3, -6, and 10 was correlated to prognosis as well as clinical and pathological parameters. RESULTS: Glut-1, Glut-3, Glut-6, and Glut-10 were expressed in 22.0, 66.0, 38.0, and 43.3 % of the analyzed samples. Whereas Glut-1, -6, and -10 did not show a correlation with prognosis, positive staining for Glut-3 was associated with higher UICC stage and inferior prognosis. The mean overall survival was 38.6 months for Glut-3 positive patients, as compared to 51.2 months for Glut-3 negative patients (p < 0.05). Coexpression of two or more of the analyzed glucose transporters was correlated to inferior prognosis. Glut-3 and UICC stage were significant prognostic factors in multivariate analysis. CONCLUSIONS: All of the analyzed glucose transporters were expressed in a significant proportion of the gastric cancer samples. Glut-3 was associated with higher UICC stage and inferior prognosis. These findings are relevant to therapeutic approaches that target glucose metabolism as well as to imaging using radioactively labeled glucose.

Immune checkpoints programmed death 1 ligand 1 and cytotoxic T lymphocyte associated molecule 4 in gastric adenocarcinoma.

Remarkable efficacy of immune checkpoint inhibition has been reported for several types of solid tumors and early studies in gastric adenocarcinoma are promising. A detailed knowledge about the natural biology of immune checkpoints in gastric adenocarcinoma is essential for clinical and translational evaluation of these drugs. This study is a comprehensive analysis of cytotoxic T lymphocyte associated molecule 4 (CTLA-4) and programmed death 1 ligand 1 (PD-L1) expression in gastric adenocarcinoma. PD-L1 and CTLA-4 were stained on tumor sections of 127 Caucasian patients with gastric adenocarcinoma by immunohistochemistry (IHC) and somatic mutation profiling was performed using targeted next-generation sequencing. Expression of PD-L1 and CTLA-4 on lymphocytes in tumor sections, tumor-draining lymph nodes (TDLN) and peripheral blood were studied by flow-cytometry and immune-fluorescence microscopy in an additional cohort. PD-L1 and CTLA-4 were expressed in 44.9% (57/127) and 86.6% (110/127) of the analyzed gastric adenocarcinoma samples, respectively. Positive tumor cell staining for PD-L1 or CTLA-4 was associated with inferior overall survival. Somatic mutational analysis did not reveal a correlation to expression of PD-L1 or CTLA-4 on tumor cells. Expression of PD-1 (52.2%), PD-L1 (42.2%) and CTLA-4 (1.6%) on tumor infiltrating T cells was significantly elevated compared to peripheral blood. Of note, PD-1 and PD-L1 were expressed far higher by tumor-infiltrating lymphocytes than CTLA-4. In conclusion, specific immune checkpoint-inhibitors should be evaluated in this disease and the combination with molecular targeted therapies might be of benefit. An extensive immune monitoring should accompany these studies to better understand their mode of action in the tumor microenvironment.