From clinical, chemical carcinogenesis and transgenic animal studies, it is evident that wounding has a tumor-promoting effect. We discuss the role of TGF-beta (with special emphasis on TGF-beta 1) in this process and suggest that stromal alterations during wound healing, induced by TGF-beta, can be an important determinant of tumor growth. A tumor and a wound both require similar stromal microenvironments. Thus, a chemically initiated or an oncogene-expressing cell could be complemented to grow into a tumor if it finds itself in a hospitable wound-healing stroma.