ERBB2 and ductal breast carcinoma in situ: It is possible therefore (and even likely, given the association of PPARγ expression with Grade 1 in invasive breast cancer[48]) that PPARγ expression in Grade 1 DCIS is more frequent than what we see in our population, but this awaits a larger study, and may require the use of whole sections rather than TMAs, As with COX-2 positivity, there was no association of PPARγ positivity with age or HER-2 status, although it has been reported in one study that PPARγ may inhibit HER-2 pathways in cell culture models[49].