NPB and nasopharyngeal carcinoma: Romanello et al.[15▪] using a similar derivative and LC-APCI-MS/MS found plasma levels of NPC (median 48.44 ng/ml, IQR 24.86–60 ng/ml, n = 17) and also NPB (median 35.21 ng/ml, IQR 26.12–60.39 ng/ml, n = 8) elevated above control values (median 9.03 ng/ml, IQR 7.38–11.34 ng/ml, n = 60).