ALDH1A1 and ovarian cancer: Given that the ALDH1A1 inhibitor NCT-501 can offset DDB2 silencing-induced non-CSC-to-CSC conversions, we reasoned that inhibition of ALDH1A1 activity is also able to reduce the CSC subpopulation and diminish their tumorigenicity in ovarian cancer cells carrying a low level of DDB2.