ALK and small cell lung carcinoma: The current guideline of CAP/IASLC/AMP suggests that testing for EGFR mutations and anaplastic lymphoma kinase (ALK) translocations should be recommended for adenocarcinomas and mixed lung cancers with an adenocarcinomatous component, regardless of histologic grade, and are not recommended in lung cancers that lack any adenocarcinoma component, such as “pure” SqCC, “pure” SCLC, or large cell carcinomas lacking any IHC evidence of adenocarcinoma differentiation [20].