CYP1B1 and neoplasm: Their results also confirmed the importance of DMBA dihydrodiol epoxide production at the site of cancer development, whereas tissue specific constitutive expression of CYP1B1 may contribute to cancer susceptibility in the human population.48 Simon et al., evaluated the human lung expression of CYP1B1 in tumor and non-tumor tissues of 16 individuals through qualitative reverse transcription-polymerase chain reaction and western immunoblots.