ALDH1A1 and breast cancer: After further analysis of the clinical data from the included studies (Supplementary Table S3), Kaplan–Meier survival analysis revealed that high expression levels of both ALDH1A1 and UBE2L6 were protective against breast cancer (HR 0.71 and 0.69, respectively, p < 0.05), whereas high expression levels of RDH16 were associated with a high risk of developing the disease (HR = 1.39, p < 0.05) (Figure 8).