ITGA5 and neoplasm: Other signaling axes include NESC and PC clusters as sender of the extracellular matrix (ECM) protein fibronectin (FN1) to the integrin receptor complexes ITGA4/B1 and ITGA5/B1 on several tumor and myeloid receiver clusters as well as BEC and LEC clusters as sender of the adhesion molecule PECAM1 to CD38+ tumor and myeloid cell populations (Fig. 4G, H).