ALDH1A1 and ductal breast carcinoma in situ: In these 47 DCIS cases, no significant association was observed between ALDH1 positivity and age (P = 0.528), tumor size (P = 0.951), grade (P = 0.812), ER status (P = 0.428), Her2 status (P = 0.536), or Ki67 (P = 0.667).