[Immunohistochemical and molecular-pathologic investigations in dermatohistology].

Despite sophisticated diagnostic algorithms, pure morphologic diagnosis has reached its limits in many areas of general and dermatologic pathology, especially in the wake of advances in basic sciences. Modern microscopic diagnosis, especially when evaluating lymphocytic and mesenchymal tumors, depends greatly on identifying the expression of surface markers (for example CD3 as T-cell surface receptor), signal proteins (cyclin D in cell cycle control) or structural proteins in tumor cells (actin in myogenous cells). Molecular biological methods include those techniques which make it possible to identify cellular and extracellular macro-molecules such as proteins and nucleic acids. At the protein level, the selective identification of proteins on sections via immunohistochemical methods is a widely used and essential component of modern pathologic-anatomic diagnosis.