Furthermore, to confirm the results with LGG, PAAD, SKCM, and STAD, we examined whether COL4A1 expression levels were correlated with those of immune marker genes in gliomas, pancreatic tumors, melanomas, and gastric cancers using microarray-based datasets as the COL4A1 expression predicted poor overall survival in patients with these tumors, as shown in Figure S2. Here, COL4A1 is linked to gastric cancer.