P1-04-08: Distribution of ALDH1 Positive Stem Cells in Benign Mammary Tissue from Women with and without Breast Cancer.

Abstract

Abstract Background and Aims. ALDH1 in female breast tissue has been linked to stem cells, but little is known about the benign cellular organisation in situ. We investigated the distibution of ALDH1 immunoreactive (ALDH1+) cells in histomorphologically benign breast tissue from 28 women with or without breast cancer. Methods and Results. ALDH1+ cells were detected in benign tissue of women age 20 - 72, located most commonly within the luminal and intermediate ductular levels and in the stroma. ALDH1+ cell populations and Ki-67+ cell populations were present in separate ductules, both cell types rarely showing epithelial differentiation. ALDH1 + cells were non-reactive to Ki-67 and oestrogen receptor. Stromal round/oval ALDH1+ non-leukocyte cells in both age groups expressed contractile protein. There was a lower concentration of luminal and intermediate ductular ALDH1+ cells in post-menopausal women than pre-menopausal women, lower in cancer than non-cancer patients, and higher in women on exogenous hormones. Conclusions. The study provides further evidence for the stem cell character of ALDH1+ cells, here in benign breast tissue of cancer and non-cancer women throughout non-lactating adult life, and contributes evidence of benign stromal ALDH1+ cells. The distribution of ductular ALDH1+ stem cells appears to be influenced by hormonal status. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-04-08.