The methylation level of four genes (CPA1, CUL7, LRRTM2 and POU2AF1) increased both from normal to DCIS and from DCIS to IBC, while 10 genes (ARSJ, CES8, FAIM2, GPRC5B, ICAM2, P4HA3, PGLYRP2, PLOD1, PNMAL2, STAP2) showed a decrease in methylation between normal and DCIS, but an increase in methylation from DCIS to IBC. Here, CPA1 is linked to ductal breast carcinoma in situ.