ERBB2 and neoplasm: The HER2 tumor type is hypomethylated at CpG sites represented by probes 3 and 4 (Fig 4D and 4E); while the basal tumor subtype is hypomethylated at CpG sites corresponding to probes 3, 4, 7, 8, and 9 (Fig 4D, 4E, 4H to 4J).