FOLH1 and plasma cell myeloma: To date, increased PSMA-avidity in multiple myeloma has been described only sporadically in the literature [6,7,8] Of note, in a single case, PSMA expression was additionally shown to decrease after systemic therapy, highlighting PSMA-expression as a potential theranostic target for multiple myeloma, e.g., during radioligand therapy using 177Lu- or 225Ac-labeled PSMA-ligands [9].