However, the choice of a suitable SP-A antibody is highly important since approaches using polyclonals display cross reactions with other tumors [44] . This procedure has already become a part of pathological routine diagnosis, and -along with other markers such as the Thyroid-transcription-factor-1 (TTF-1) -the detection of SP-A (by PE-10) is a useful part of the immunohistochemical panel in pulmonary pathology.