Figure 3. Diagnostic algorithm that uses immunohistochemistry (IHC) as the primary test for identification anaplastic lymphoma kinase (ALK) positive in lung adenocarcinoma.

Dot lines correspond to that we also recommend initial ALK testing practice begins with IHC and fluorescence in situ hybridization (FISH) combined test, which would help be familiar with the relation of the IHC semiquantitatively score and FISH. ^aTTF-1, thyroid transcription factor-1; ^bPC%, percentage of positive cells; ^cfailed, no interpretable, or limited tissue; ^dEGFR, epidermal growth factor receptor.