SERPINA1 and gastric cancer: Using the top nine upregulated genes (CHGA, PCSK1N, TTR, DEPP1, BTG2, ATF3, SERPINA1, MDK, FOS) as a representative gene set for the lmCluster4 (Figure 5G), we calculated the GSVA score of this gene set for each patient in the TCGA gastric cancer cohort.