Morphological Characteristics of the Stroma in Malignat Epithelial Neoplasms with Short Review of Skin Squamous Cell Carcinoma

Abstract The stroma of the neoplasm is a highly complex structure built by: specialized mesenchymal cells typical for each tissue surroundings, cancer associated fibroblast/myofibroblast, congenital or acquired immune cells, vascular network with endothelial cells and pericytes, mastocytes, macrophages, leukocytes and adipocytes, all together incorporated in the extracellular matrix. Each neoplasm produces its own unique microenvironment where the tumor grows and modifies. Although most of the cells of the host in the stroma have compulsory tumor suppressor ability, the stroma is changing during the malignant process and it even promotes growth, invasion and metastasis. Genetic changes that occur during the development of the cancer, which are guided by the malignant cells lead to changes in the stroma of the host that will overtake it and adjust it to their own needs. In the early stages of the tumor development and invasion, the basal membrane is degraded and the stroma becomes active and contains an increased number of fibroblasts, inflammatory infiltrate and newly composed capillaries which come into direct contact with the tumor cells. These changes lead to cancer invasion.