Stem Cells In Colorectal Tumors Found By Stanford Researchers

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Stem Cells In Colorectal Tumors Found By Stanford Researchers

Article Date: 10 Jun 2007 - 1:00 PDT

Researchers at the Stanford University School of Medicine have

identified the cancer stem cells that propagate tumors in colon and

rectal cancer, a discovery that could lead to improved treatment of

this deadly cancer.

These are the latest class of cancer stem cells tracked down by a

large, interdisciplinary group of researchers led by e,

MD. The discovery is reported in the advance online edition of the

Proceedings of the National Academy of Sciences.

" This work will enable us to better understand how to identify these

cells, and to do molecular studies to find potential new therapies, "

said e, the senior author of the paper and the Karel H. and

Avice N. Beekhuis Professor in Cancer Biology.

e was the first to find cancer stem cells in a solid tumor - in

this case, breast cancer - in 2003 while working at the University of

Michigan. Since coming to Stanford in 2005, he joined existing

efforts that have resulted in finding cancer stem cells in head and

neck, pancreatic and now colorectal tumors.

These stem cells act like a spring at the source of a creek,

constantly dividing to produce new tumor cells. Although the other

tumor cells can divide and cause damage through their sheer bulk,

they are shorter lived and can't maintain the tumor's growth. The

cancer stem cells are also likely to be responsible when tumors

spread to distant sites.

Identifying new cancer stem cells has been a major push within

Stanford's Institute for Stem Cell Biology and Regenerative Medicine,

where e serves as associate director. Irving Weissman, MD,

director of the institute, said he hopes Stanford researchers will

develop cancer therapies that specifically kill these cancer stem

cells, eradicating the cancer entirely. Current therapies may kill

the bulk of the tumor cells, but if any cancer stem cells remain the

tumor will resurface or spread.

" We have brought together a team of scientists and clinicians who

will help find the weak points in cancer, devise new immune and

molecular diagnostics and therapeutics, test them in mice that carry

the cancer stem cells and, hopefully, in a few years begin to test

them in our patients, " Weissman said.

The colorectal cancer stem cells highlight the importance of a

protein that is a familiar face to this group of cancer researchers.

A protein called CD44 that has already been found dotting the surface

of both breast and head and neck cancer stem cells also turns up on

the colorectal cancer stem cells. To Piero Dalerba, MD, postdoctoral

scholar and first author of the paper, that finding could simply

reflect the fact that all of those tumors arise from similar tissue.

It could also mean that a similar therapy could target all three cell

types.

Dalerba also found a novel protein on the colorectal cancer stem

cells, called CD166, that had not previously been associated with

cancer stem cells. " This is one of the major novelties of this

paper, " he said. This protein could be a unique target for

identifying and treating colorectal cancers.

Colon and rectal cancers are the second-most common cause of cancer-

related deaths in the United States, killing more than 50,000 people

each year. The tumors often go undetected until they are at a later

stage and are difficult to treat. Treatment can include chemotherapy,

radiation or surgery. However, Shelton, MD, assistant

professor of surgery who treats colon cancer patients and

participated in this study, said it's often hard to know which

patients will respond best to the different treatment options.

Shelton said that grouping patients according to the treatments most

likely to work for them is one possible future benefit of finding the

cancer stem cells. In breast cancer, e and another team of

researchers recently found a group of genes that show unique patterns

of being turned on or off in people who either do or don't respond

well to treatment. The group hopes to do similar work with the

colorectal cancer stem cells as a first step in identifying patients

who may need more aggressive treatment.

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Other Stanford researchers who contributed to the work include

Cho, MD, clinical assistant professor of pediatrics.

The work was supported by the National Institutes of Health, the

Virginia and D.K. Ludwig Foundation, the California Institute for

Regenerative Medicine, and the Fondazione Italiana per la Ricerca sul

Cancro.

Stanford University Medical Center integrates research, medical

education and patient care at its three institutions - Stanford

University School of Medicine, Stanford Hospital & Clinics and Lucile

Packard Children's Hospital at Stanford. For more information, please

visit the Web site of the medical center's Office of Communication &

Public Affairs at http://mednews.stanford.edu/

Contact: Amy

Stanford University Medical Center