Extracellular matrix synthesis by undifferentiated childhood tumor cell lines

The authors have examined extracellular matrix (ECM) biosynthesis by small round cell tumors of childhood. Basal lamina (laminin and Type IV collagen) and stroma (collagens I, III, and V and fibronectin) constituents were studied. It was found that these tumors synthesize ECM in characteristic patterns. Five Ewing's sarcomas variably synthesized small amounts of all ECM constituents except Type V collagen. All eight neural tumors (neuroblastoma and primitive neural tumors) synthesized fibronectin (unlike some Ewing's sarcomas), as well as laminin and Type IV collagen (2 cases lacked Type IV collagen synthesis). No stromal (I/III) collagen synthesis was observed by neural tumors. All soft tissue sarcomas except an embryonal rhabdomyosarcoma synthesized stromal collagens and often laminin or fibronectin as well. Lymphomas synthesized no ECM of any kind. The synthesis of stromal collagens by sarcomas but not neural tumors serves to distinguish these two tumor types, especially Ewing's sarcoma from neuroblastoma. The presence of any ECM synthesis excludes lymphoma from diagnostic consideration.