Expression of aromatase CYP19 and its relationship with parameters in NSCLC.

Human aromatase (CYP19) responsible for the conversion of androgens to estrogens is expressed not only in gonads and adrenals but also in many other tissues, including normal lungs and lung cancers. To investigate the involvement of CYP19 in lung cancer development, purified CYP19 protein and antibody are required. In this study, we have developed an efficient expression method of human aromatase in E. coli (>1000 nmol/L culture). The protein purified from E. coli was used to raise an antibody against the human CYP19 in rabbits. The resulting antibody showed a high titer judged by ELISA, which allowed us to determine the expression of CYP19 in non-small cell lung cancer (NSCLC). Of 78 NSCLC specimens from Japanese patients, 50 (64%) NSCLC aberrantly expressed CYP19. This CYP19 expression in NSCLC was independent of any clinical and pathological parameters as well as the expression of other P450s, except tumor stage. The results suggest that the aromatase inhibitors might be useful for the management of non-small cell lung cancer in postmenopausal women.