Gene’s Isolation May Aid in War on Cancer

Scientists have isolated a gene that prevents a rare form of cancer, a discovery that could improve understanding of the natural controls that go awry when tumors strike. The finding also may enhance the ability to identify people who may be likely to get cancer because this gene is either missing or deformed.

Reporting on their work in the current issue of the British journal, Nature, researchers in Boston said they have cloned the first of a class of genetic switches, called recessive oncogenes, that normally keep cancer from occurring. They said children born without a complete copy of this gene face a high risk of getting rare forms of eye and bone cancer called retinoblastoma and osteosarcoma.

“These are not major diseases, but we think that the other major cancers, like some colon and breast and lung cancers, are caused because genes like this are lost,” said Dr. Thaddeus P. Dryja, an ophthalmologist at Massachusetts Eye and Ear Infirmary. “We think that recessive oncogenes are important in many cancers. It’s just that nobody has ever cloned one of these genes for any cancer until now.”

Experts believe there are two kinds of oncogenes: those that cause cancer by their presence and those that cause it by their absence. Both types are mutant or incomplete versions of ordinary genes that normally regulate cell growth.

Dryja said a next research goal is to figure out what kind of signal this gene sends to stop cancer. That information may help decipher the genetic origins of more common forms of the disease.