ALK and cancer: Among these cancers, ALK gene fusions were identified to be most common in ALCL (60% cases, mainly NPM-ALK fusion) [9], followed by IMT (~50% cases, mainly TPM3/4-ALK fusion) [10], NSCLC (~5–7% cases, mainly EML4-ALK fusion) [11], and other cancers [8,12,13,14,15] (Table 1).