Epithelial tumor, invasion and stroma.

Uncontrolled proliferation is a defining feature of the malignant phenotype. Nevertheless, the supportive network provided by the stroma is indispensable for further invasion, progression and metastasis of cancer cells. In addition, the role of inflammation in tumorigenesis is now generally accepted, and it has become evident that an inflammatory microenvironment is an essential component of tumor progression. Since skin tumors are common and easily assessable lesions with features at various stages of tumorigenesis, they provide a wide scope for research in this field to further our understanding of fundamental and clinical carcinogenesis. Some of the basic aspects of epithelial tumorigenesis, invasion and stromal reaction are reviewed in this paper.