The bachelor thesis 1 deals with lung cancer, which is one of the most common carcinomas worldwide. First, an overview of the current epidemiology of lung cancer is given, the sample collection and processing is explained and the methods used to establish the diagnosis are subsequently defined. The main focus is on the description of the individual tumour types of lung carcinoma, which are morphology and immunocytochemistry. In addition the morphology is being explained using pictures. Based on this, all appropriate immunocytochemical antibodies, which are necessary for the diagnosis and which can be recognized with the aid of images in the microscope, are described. The last important area of the bachelor thesis 1 deals with the importance of immunocytochemistry within the diagnosis of lung carcinoma and what causes it could have, that the cytological morphology does not cover with the immunocytochemistry. From the sample collection to the assessment, all relevant sources of error were explained.