This may also explain why other authors did not see correlation between apparent rates of midazolam conversion to 1-OH midazolam (measured without the glucuronidase treatment step) and clearance of erlotinib in patients with lung cancer, despite the fact that this drug is known to be extensively metabolized by CYP3A4 (Parra-Guillen et al., 2017). This evidence concerns the gene CYP3A4 and lung cancer.