AHR and lung adenocarcinoma in situ: CYP1A1 expression has further been reported in 40 out of 107 human lung adenocarcinomas and 21 out of 57 mixed bronchioalveolar carcinomas by immunohistochemistry, whereas the expression of both AhR and CYP1A1 was associated with smoking in lung adenocarcinoma patients [74].