Three peptides derived from RNA-seq and κ light chain assembly using tumor cells from Patient 1 were observed with LC-MRM in a serum sample with 0.2g/dl M-protein: VTITCR (A), SLIYAASSLQSGVPSK (B), and ANQDITNSLVWFQQK (C). Data are provided from Patient 2 to illustrate the uniqueness of the three peptides (B, D, and F, respectively).