Detection of ERG peptide VIVPADPTLWSTDHVR from LNCaP cells. Different amounts of recombinant ERG3 protein (6.7 pg, 20 pg, 67 pg, 400 pg) was spiked into LNCaP cells. A. XICs of peptide VIVPADPTLWSTDHVR from the different data points. Heavy indicate heavy internal standard peptide; Light indicate endogenous peptide. N.D.: not detected. B. Response curve.