Retroviruses and Oncogenes

It is relatively easy to identify and isolate retrovirus oncogenes and their products. 

Gene therapy offers another potential avenue to fix the defective gene. The therapy itself is by no means straightforward. In a French gene therapy trial, three boys with SCID were treated using retrovirus-based gene therapy. They later developed cancer and one died of leukemia. Reviews showed that the retrovirus inserted near oncogenes and promoted development of cancer. 

Hsieh, L. L., Shinozuka, H., and Weinstein, 1. B. (1991). Changes in expression of cellular oncogenes and endogenous retrovirus-Uke sequences during hepatocarcincgenesis induced by a peroxisome proliferator. Br J Cancer 64, 815-820. 

In addition to the oncogenes of Rous sarcoma virus, dozens of oncogenes of other retroviruses have been recognized. Products of these viral oncogenes are protein kinases, mostly of the tyrosine type. Some viral oncogenes and their products are listed in Table 1. 

Some retroviruses contain cancer-causing genes (oncogenes), and cells Infected by such retroviruses are oncogenically transformed into tumor cells. Studies of oncogenic retroviruses (mostly viruses of birds and mice) have revealed a great deal about the processes that lead to transformation of a normal cell into a cancer cell (Chapter 23). 

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