Fibroblast heterogeneity refers to both phenotypic and functional properties exhibited by a fibroblast population within or across tissues (Mc Culloch et al.). There is significant evidence that fibroblasts are heterogeneous with respect to functional properties. Certain subpopulations of these cells may be clonally selected and expanded in diseased tissues. There are wide variations in gene expression and strikingly different responses to extracellular signals among different fibroblast populations. This has prompted a large number of in vitro studies, which suggest that fibroblasts are not homogeneous. Instead, they comprise multiple subpopulations with extensive site-to-site and intra-site variations.