Concentrations of plasma LEN (N = 225) and CYP3A biomarkers (cortisol, 6β‐hydroxycortisol, deoxycholic acid, and 1β‐hydroxydeoxycholic acid) in urine (N = 214) from 20 patients (hepatocellular carcinoma, N = 6; thyroid cancer, N = 3; endometrial cancer, N = 8; and renal cell carcinoma, N = 3) collected for consultation for up to 1 year were evaluated using liquid chromatography–tandem mass spectrometry. The gene discussed is CYP3A4; the disease is thyroid cancer.