In multivariable analysis, DS, but not nuclear grade, correlated with the benefit of radiotherapy in the SweDCIS cohort.18 In collaboration with Genomic Health Inc, we have described a 12-gene signature for DCIS.19 This signature is based on mRNA levels of progesterone (PgR), Glutathione S-Transferase Mu 1 (GSTM1) and 5 proliferation genes (MKI67, STK15, BIRC5, CCNB1, and MYBL2). Here, GSTM1 is linked to ductal breast carcinoma in situ.