ALDH1A1 and breast neoplasm: Further, in comparison with data derived from breast tumours in Caucasian and Asian populations (Ginestier et al, 2007; Morimoto et al, 2009; Tanei et al, 2009) regarding ALDH1 positivity rate in tumours with similar characteristics (histological grade, ER, HER2, Ki-67), we observed that tumours from our present series stained in a higher percentage of cases in most poor prognosis categories (such as high histological grade, ER-negative cases, HER2-negative cases, tumours with high Ki-67 expression).