ALDH1A3 and breast cancer: Other ALDH isoforms have been mechanistically associated with metastatic behavior in vitro, including ALDH1A3 in breast cancer [9, 10], melanoma [65], pancreatic cancer [107] and brain cancer [108]; ALDH3A1 in prostate cancer [109] and liver cancer [110]; and ALDH7A1 in prostate cancer [11].