CALCA and neoplasm: Studies with clinical samples and in primary culture of tumor cells have shown that, although benign pheochromocytomas secrete more AM than malignant ones, both share comparable expression levels of AM and (and CGRP) receptor components (CLR and RAMPs), RAMP1 being markedly abundant (up to 12-fold) with respect to RAMP2 and RAMP3 (140).