It is evident that SP-A is a molecule which already proves to be an interesting subject for medical research. However, the studies concerning the possible role of surfactantdefects in pulmonary diseases of adults have been performed mainly in different cell culture or animal models hardly analyzing adult human lung tissue. For these reasons SP-A is a promising target for histomorphological approaches using pathological specimens which exactly represent the scenarios of various diseases with all the different cell types involved which are difficult to simulate in models. With the modern tools of molecular pathology, the genetic activities of genes can be analyzed in situ, which provides evidence of the cellular activities in the context of a human native tissue. One example is shown Immunohistochemical detection of SP-A using the mono-clonal antibody PE-10 (LSAB, amonoethylcarbazole, 400×) Figure 2 Immunohistochemical detection of SP-A using the monoclonal antibody PE-10 (LSAB, amonoethylcarbazole, 400×).