EML4 and non-small cell lung carcinoma: All reported EML4-ALK variants, including even the shortest variant 5a/b, contain the EML4-cc domain; in the non-EML4 ALK fusion partners reported in NSCLC (e.g., KIF5B-, TPM3-, TPM4-, or TPR-) the amino-terminal fragment of the fusion partner necessarily contains cc domains or oligomerization domains (13–15).