Tumor suppressor gene family may be key to new colon ca...( In the hunt for new cancer drug targets...),Health

In the hunt for new cancer drug targets, scientists from the Johns Hopkins Kimmel Cancer Center and the Howard Hughes Medical Institute have discovered mutations in a family of genes linked to more than a quarter of colon cancers, as well as several other common cancers including breast and lung. Their research, published in the May 21, 2004 issue of Science, reveals more options for creating personalized therapies tailored to counteract mutated gene pathways present in individual tumors.

"What makes this discovery significant is that we've found mutations that directly affect cancer development," says Victor Velculescu, M.D., Ph.D., senior author of the study and assistant professor at the Johns Hopkins Kimmel Cancer Center. "Most gene discoveries today focus on finding increased or decreased activity of a gene that may not affect cancer progression, akin to passengers on a bus that can't control the bus' speed or direction. What we've found are the brakes of the bus."

After analyzing 157 colon cancers, the research team found 77 mutations in six genes that make tyrosine phosphatases, enzymes that help coordinate signals that manage cellular growth, death, differentiation, and nearby tissue invasion. They normally work by turning off tumor growth, as so-called tumor suppressors, but in cancers these genes are mutated and no longer work properly. Because it is difficult to restore a mutated suppressor gene with cancer drugs, the investigators believe phosphatases themselves are not good drug targets. Yet, for every tyrosine phosphatase there is a matching enzyme, called a tyrosine kinase, which plays an opposite role, turning a pathway on and accelerating cellular events.

"If a bus' brakes are broken and they can't be fixed, another way to slow it down is to let up on the accelerator," explains Velculescu. "In this case, the faulty brakes are mutated tyrosine phosphatases and the accelerators are the tyrosine kinases." Tyrosine kinas
'"/>

Contact: Vanessa Wasta
wastava@jhmi.edu
410-955-1287
Johns Hopkins Medical Institutions
20-May-2004

Page: 1 2
Related medicine news :

1. Tumor-targeted immune cells cure prostate cancer in mice without causing systemic immune suppression
2. Tumor size alone not always best for gauging treatment response
3. Tumor suppressor genes predict bladder cancer future
4. Tumor characteristics may help predict survival in breast cancer patients
5. Tumor vaccine to begin clinical trials
6. Tumor size predicts survival in patients with lung cancer
7. Tumor vaccines via dendritic cells
8. Jefferson Scientists Show Tumor Characteristics May Help Explain Tumor Biology And Prognosis
9. Marker Found For The Most Malignant Brain Tumors
10. Stress And Surgery May Increase Development Of Cancerous Tumors
11. UCSF And Eight Other Medical Centers Chosen For National Cancer Institutes Pediatric Brain Tumor Consortium