Fig. 5
Construction and validation of a SiaM-based model for predicting clinical outcomes in gastric cancer. A Differentially expressed proteins identified from the common DEGs via proteomic limma analysis in the ZJUGC-A cohort. Red and blue points represent significantly up-regulated and down-regulated proteins, respectively. P < 0.05 & |Log1.5(Fold change)| > 1 was set as the threshold. B Identification of candidate variables for predicting peritoneal metastasis via LASSO regression analysis. The curves show that the parameters decreased to zero when the penalty (Lambda) increased. n = 6 was adopted as the best parameter. Ultimately, six candidate genes including ARHGAP6, ST3GAL1, ADAM28, C7, PLCL1, and TTC28 were enrolled in the model construction. C Correlation between the SiaM-based model (named the SiaM score) and SiaM activity in the ACRG cohort. The SiaM activity was estimated using the ssGSEA algorithm. Blue, yellow, and red dots represent cluster A, cluster B, and cluster C, respectively. D Association between the SiaM score and peritoneal metastasis in the ZJUGC-A, ZJUGC-B, ACRG, and Takeno cohorts. The comparison of the SiaM score was examined using the Mann‒Whitney test. E ROC curves showing the predictive performance of the SiaM score for peritoneal metastasis in the ZJUGC-B (blue), ACRG (red), and Takeno cohorts (green). Kaplan‒Meier curves showing the differences in overall survival between patients with low and high SiaM scores in the ZJUGC-A (F), ZJUGC-B (G), ACRG (H), and Takeno (I) cohorts. Kaplan‒Meier curves showing the differences in disease-free survival between patients with low and high SiaM scores in the ACRG (J) and TCG-STAD (K) cohorts. The HRs with 95% CIs were determined using log-rank tests. L Forest plot showing the independent predictive value of the SiaM score for peritoneal metastasis and survival outcomes via multivariate logistic and Cox regression analyses, respectively. The adjusted parameters included age, gender, Lauren type, and Bormann type. D, diffuse; M, mixed; I, intestinal; PM, peritoneal metastasis; NM, no metastasis; OS, overall survival; DFS, disease-free survival; * P < 0.05; ** P < 0.01; *** P < 0.001