ALDH1B1 and cancer: To identify the upstream signaling that regulates ALDH1B1 expression, we treated A549 cells with the inhibitors of signal pathways that have been shown to play the crucial role in cancer progression, Ravoxertinib (ERK inhibitor), Mirdametinib (MEK1/2 inhibitor), MK-2206 (AKT inhibitor), Verteporfin (YAP inhibitor), and PDTC (NF-κB inhibitor).