The prognostic significance of ALDH1A1 in breast cancer (Althobiti et al. 2020), ALDH1 in rectal cancer (Deng et al. 2014), ALDH1 in esophageal cancer (Hwang et al. 2014), and ALDH2 in oropharyngeal cancer (Shinomiya et al. 2017) has been explored by scholars. Here, ALDH2 is linked to breast cancer.