ALDH1A1 and ductal breast carcinoma in situ: ALDH1 was expressed in stromal cells in 93.5 % (43/46, one case not available) of DCIS cases, 85.0 % (51/60, two cases not available) of invasive cancer with EIC cases, and 98.2 % (56/57, one case not available) of invasive cancer without EIC cases.