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).
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.