A lung fibroblast cell line was isolated from lung biopsy of a patient with lung fibrosis. Gene expression of ten growth factors in the fibroblasts were investigated by a reverse transcription-DNA polymerase chain reaction. The results indicated that the fibroblasts expressed acidic fibroblast growth factor (aFGF) mRNA transcript. Further experiments revealed that recombinant aFGF could be internalized by the fibroblasts and stimulated the proliferation of the cells. These data suggest that aFGF may activate lung fibroblasts in a way of autocrine and, therefore, may be involved in the development of lung fibrosis.