In Taiwanese patients, methylation of TSTD1 was significantly correlated with mRNA expression of TSTD1. TSTD1 was hypomethylated in 74.2% (23/31) patients with upregulated TSTD1 expression in breast tumors (p = 0.040), whereas TSTD1 was hypermethylated in 56.3% (9/16) of patients with TSTD1 downregulation (Table S2). The gene discussed is TSTD1; the disease is breast neoplasm.