ALK and cancer: Alternative transcription, initiated by derepressed intronic LTR elements, has been shown to produce truncated oncogenic forms of tyrosine kinases, such as the anaplastic lymphoma kinase (ALK) in a subset of melanomas and other cancer types [64], and the erb-b2 receptor tyrosine kinase 4 (ERBB4) in ALK-negative anaplastic large-cell lymphoma (ALCL) [65].