[Behavior of small molecular cysteine proteinase inhibitors in lung cancers and surrounding tissue].

In this work, we have studied the occurrence of acid and neutral cysteine proteinase inhibitors in 3 histologically different lung cancers. The acid cysteine proteinase inhibitor ( ACPI ) seems to be associated to squamous differentiation as our previous observations have shown. As a new observation we could show that the neutral cysteine proteinase inhibitor ( NCPI ) was localized in alveolar macrophages.