Jhaveri and Morrow (1998) previously showed that the GSTP1 CpG island is hypermethylated in ER-positive, GSTP1-nonexpressing MCF-7, but is undermethylated in ER-negative, GSTP1-expressing cell lines. Note that, in our study, both ER- and PR-negative patients exhibited higher levels of GSTP1 expression. In a recent study, Shinozaki showed that hypermethylation of GSTP1 was significantly associated with macroscopic sentinel lymph node metastasis compared to patients with microscopic or no sentinel lymph node (Shinozaki et al, 2005). The gene discussed is GSTP1; the disease is metastatic malignant neoplasm in the lymph nodes.