SDC2 mRNA expression was notably downregulated in breast carcinoma tissues stratified by nodal metastasis status (N0, N1, N2, and N3), which aligned with our qPCR results in breast cancer tissue samples (Fig. 7A) and staging (I, II, III, and IV) relative to normal tissues (Fig. 7B). The gene discussed is SDC2; the disease is breast carcinoma.