ROC curves of CSMD2 expression in tumor and normal tissues showed that CSMD2 had high diagnostic efficiency in DLBC (AUC = 0.987, CI: 0.977–0.996), CHOL (AUC = 0.960, CI: 0.907–1.000), PAAD (AUC = 0.913, CI: 0.881–0.945), and THYM (AUC = 0.901, CI: 0.867–0.935), whereas, CSMD2 had low diagnostic efficiency in BLCA, CESC, GBM, LAML, PRAD, THCA, and UCEC, and had moderate diagnostic efficiency in other cancers (Figure 2). This evidence concerns the gene CSMD2 and cancer.