GPRC5D and Miyoshi myopathy: The wide variety of GPRC5D expression levels on several MM cell lines was evaluated by following three approaches: 1) FCM using indirect immunofluorescence assay to determine cell surface GPRC5D protein expression quantitatively, 2) droplet digital PCR (ddPCR) to determine GPRC5D mRNA expression level, and 3) IHC to determine the positivity of GPRC5D among cells (Fig. 2a, Supplemental Fig. 2).