Figure 4. Leptin promotes expansion of ALDH⁺ cell in mammospheres.

Primary human mammary epithelial cells were grown to form mammospheres in the presence of leptin (100 ng/ml), or vehicle control. After forming for 10 days, mammospheres were fixed and stained for ALDH1a1 (AlexFluor⁴⁸⁸, green) and DAPI to identify nuclei (blue). A. Representative mammosphere grown with vehicle control showing the presence of 1 ALDH⁺ cell. B. Representative mammosphere grown in the presence of leptin showing symmetric self-renewal of an ALDH⁺ cell. C–D. Frequency of distribution of number of ALDH⁺ cells per mammosphere in both conditions.