CYP26A1 and neoplasm: had shown that the CYP26 inhibitor R116010, co-applied with 13-cis-RA in animals, reduces 13-cis-RA metabolism in the liver, leading to higher levels of serum 13-cis-RA and ATRA, plus greater CYP26A1 transcription in xenografted SH-SY5Y tumours [18].