the results strongly suggest that : 1 ) the modification of collagen synthesis , content , and types observed in primary cultures of fibroblasts might be due to factors causing long-lasting changes in phenotypic expression and/in stimulation of the expansion of some fibroblast clones engaged in the accelerated synthesis of extracellular matrix macromolecules , such as collagen or non-collagenous proteins .
C0015350
extracellular matrix
C0009325
collagen