Prognostic Implications of LRP1B and Its Relationship with the Tumor-Infiltrating Immune Cells in Gastric Cancer.

Simple Summary: Gastric cancer (GC) has a poor prognosis, as it has often grown into an advanced stage when diagnosed. Genetic testing is crucial for establishing a treatment plan. In this study, next-generation sequencing (NGS) was performed to discover that LRP1B mutation was associated with a poor prognosis in GC. Through layer-by-layer research, it was found that LRP1B expression in GC was accompanied by a higher-level infiltration of CD4+ T, CD8+ T cells, and CD86/CD163. It is concluded that LRP1B expression can stimulate tumor immune cell infiltration, thus bringing clinical benefits to GC patients. Background: Recent studies have shown that low-density lipoprotein receptor-related protein 1b (LRP1B), as a potential tumor suppressor, is implicated in the response to immunotherapy. The frequency of LRP1B mutation gene is high in many cancers, but its role in gastric cancer (GC) has not been determined. Methods: The prognostic value of LRP1B mutation in a cohort containing 100 patients having received radical gastrectomy for stage II–III GC was explored. By analyzing the data of LRP1B mRNA, the risk score of differentially expressed genes (DEGs) between LRP1B mutation-type and wild-type was constructed based on the TCGA-STAD cohort. The infiltration of tumor immune cells was evaluated by the CYBERSORT algorithm and verified by immunohistochemistry. Results: LRP1B gene mutation was an independent risk factor for disease-free survival (DFS) in GC patients (HR = 2.57, 95% CI: 1.28–5.14, p = 0.008). The Kaplan–Meier curve demonstrated a shorter survival time in high-risk patients stratified according to risk score (p < 0.0001). CYBERSORT analysis showed that the DEGs were mainly concentrated in CD4+ T cells and macrophages. TIMER analysis suggested that LRP1B expression was associated with the infiltration of CD4+ T cells and macrophages. Immunohistochemistry demonstrated that LRP1B was expressed in the tumor cells (TCs) and immune cells in 16/89 and 26/89 of the cohort, respectively. LRP1B-positive TCs were associated with higher levels of CD4+ T cells, CD8+ T cells, and CD86/CD163 (p < 0.05). Multivariate analysis showed that LRP1B-positive TCs represented an independent protective factor of DFS in GC patients (HR = 0.43, 95% CI: 0.10–0.93, p = 0.042). Conclusions: LRP1B has a high prognostic value in GC. LRP1B may stimulate tumor immune cell infiltration to provide GC patients with survival benefits. [ABSTRACT FROM AUTHOR]