TTF1 and squamous cell lung carcinoma: However, the comparable but independent staining pattern of both markers in malignant mesothelioma, adenocarcinoma, and squamous cell carcinoma of the lung may suggest that TROP2 may complement the list of biomarkers that are most commonly used for this purpose such as calretinin, WT1, D2-40, cytokeratin 5/6, TTF-1, CEA, EpCAM, and Napsin A [31].