We have investigated the expression of the dbl protooncogene in a wide variety of human tumors of different embryological derivation. We found that proto-dbl mRNA could be detected preferentially in a few neoplastic histiotypes of neuroectodermal origin. The common, normal 5-kilobase size of the proto-dbl transcript detected indicated that the proto-dbl in these tumors was not rearranged. These data, in agreement with our previous reports, suggest that the dbl protooncogene is expressed in a highly tissue-specific manner and indicate that this gene may be involved in the growth and differentiation of some cells of neuroectodermal origin
