PTGS2 and ductal breast carcinoma in situ: Recently, a large study (n = 1162) of biomarker expression in ductal carcinoma in situ (DCIS) was published ( Kerlikowske et al., 2010) where it was shown that the diagnosis of breast tumors by palpitation or the concurrent triple expression of p16/COX-2/Ki67 signified an increased risk of recurrence of invasive breast cancer 8 years following initial diagnosis and lumpectomy.