[Tumor cells and extracellular matrix with special reference to mamma tumors in dogs and cats]

The essence of the cell-matrix interaction in tissues is that cells influence the composition of the extracellular matrix but that, on the other hand, components of the matrix are also involved in the regulation of growth and differentiation of the cells. Interaction is also found to occur in tumours though in a different way, so that infiltration and metastasis and the occurrence of scirrhous carcinomas are the result. Canine and feline mammary tumours are interesting objects for the study of this interaction since fibroadenomatous changes, in which connective tissue is the predominating tissue, is a common finding in cats only, whereas mixed and complex mammary tumours, producing matrix components of varying type, are common tumours in dogs.