Tumors Arise by Mutational Events in Cellular Protooncogenes

Many Tumors Arise by Mutational Events in Cellular Protooncogenes 

A growing number of cellular genes have been implicated in a wide variety of cancers. These genes do not lead to cancers in their normal state but only after a mutational event 

Translocation associated with Burkitt s lymphoma. The protooncogene c-myc, on the end of chromosome 8q, is translocated to the end of chromosome 14q, adjacent to the immunoglobulin constant gene, Ig-CfJL. (From J. Yunis, The chromosomal basis of human neoplasia. Science 221 227-236, Jan. 1, 1983. Copyright 1983 by the AAAS. Reprinted by permission.) 

The Philadelphia chromosome arises by a reciprocal translocation between chromosomes 9 and 22. Note that the abl protooncogene is moved in the translocation process. 

Oncogenes Are Frequently Associated with Tumor-Causing Viruses 

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