In this study, we report the technical development and initial genomic and clinical validation of a new slide-based, enrichment-free immunofluorescence assay (i.e., BCMA, CD138, CD45, DAPI) for the detection of circulating rare cells and morphogenomic profiling of BCMA+ cells in PC malignancies, hereafter referred to as the “BCMA assay”. This evidence concerns the gene SDC1 and pachyonychia congenita.