Pan-cancer analysis of PSAP identifies its expression and clinical relevance in gastric cancer

Prosaposin (PSAP) plays a critical role in sphingolipid and cancer metabolism. Reports have shown that PSAP was involved in proliferation, tumorigenesis, and metastasis. However, the expression pattern of PSAP and its prognostic roles in gastric cancer remain elusive. PSAP expression pattern and its prognostic roles in gastric cancer (GC) were explored using data from the TCGA and Kaplan-Meier Plotter. Immunohistochemical staining of GC tissues was performed to validate the prognostic role of PSAP. TISIDB was used to analyze its correlation with immunomodulators. PSAP-associated genes, PDCD1, TGFB1, and CSF1R were used to build a risk model to evaluate immunotherapy outcomes of patients with stomach adenocarcinoma (STAD). Results showed that PSAP was highly expressed in GC. High PSAP expression in GC patients also significantly indicated a poor prognosis. The results of immunohistochemical staining showed that PSAP was an independent prognostic factor in GC patients. Based on three PSAP-associated genes, a risk model that could predict the prognosis and immunotherapy outcome of STAD was bulit. PSAP was an independent prognostic factor in GC. Our results have identified three prognosis-related genes which were useful to evaluate immunotherapy outcomes of STAD patients.