JAK2 and NOTCH2 in gastric cancer – NOTCH2 is an independent prognosticator of poor patient outcome

Gastric carcinomas occasionally harbor genetic alterations of JAK2 and NOTCH2. In this study we investigated the tumor biological significance of JAK2 and NOTCH2 in gastric carcinoma. The expression of JAK2 and NOTCH2 was studied by immunohistochemistry using whole mount tissue sections obtained from 447 resection specimens of gastric adenocarcinomas. A Histoscore was generated and expression data were correlated with patient survival and clinicopathological patient characteristics. Both JAK2 and NOTCH2 were heterogeneously expressed intratumorally in gastric cancer. The number of cases showing high expression of JAK2 (5.4%) and NOTCH2 (3.4%) was low matching with genetic data retrieved from cBioPortal. NOTCH2 was an independent prognosticator of poor outcome (tumor-specific survival: 16.7 ± 1.5 months in the NOTCH2 "low" vs. 7.2 ± 0.7 months in the NOTCH2 "high" cohort; p = < 0.001). To the contrary, patients with little or no expression of JAK2 showed a worse tumor-specific survival (15.4 ± 1.3 months in the JAK2 "low" group vs. 19.5 ± 13.1 months in the JAK2 "high" group; p = 0.041). No correlation was found between expression of JAK2 and NOTCH2. JAK2 and NOTCH2 are differently expressed in gastric adenocarcinoms and of putative tumor biological significance. Particularly NOTCH2 turned out to be an independent prognosticator of poor patient outcome.