From the analysis of normalized RNA expression data from the TCGA datasets, we found that breast tumors exhibited the highest levels of SEMA3C expression (proteinatlas.org) compared to other cancer types, and by comparing its expression in breast normal vs. breast tumors using GEPIA2, we confirmed higher mRNA expression in breast tumors than matched normal TCGA and GTex samples (p < 0.05) [19,27] (Figure S1). The gene discussed is SEMA3C; the disease is breast neoplasm.