Normal ALK protein expression is restricted to the nervous systems of adult mammals, but the aberrant expression of ALK has been observed in a variety of pediatric cancers, including glioma and Ewing sarcoma.
Cell lines established from solid tumors of ectodermal origin, including melanoma and breast carcinoma, exhibited widespread mRNA expression of the ALK receptor at a broad range (53/64), an association which was found to be strongest in cell lines derived from neuroblastoma (6/6), glioblastoma (8/8) as well as in cell lines established from Ewing sarcoma (4/4) and retinoblastomas (2/2).