ALDH1A3 and lung carcinoma: Similar to prior studies, we found the response to be variable, with the ALDH1A3-positive cell lines showing no STRA6 induction, including A375 (melanoma), LN229 (glioblastoma), MDA-MB-468 (breast cancer), NCI-H358 (lung cancer), and SUM159-M1a (breast cancer), while ALDH1A-negative cell lines, including MCF7 and MDA-MB-231 (breast cancer), showed more than 10-fold increases in STRA6 transcription upon atRA treatment (Figure 1A).