Some Tumors Contain Factors that May Block Metastasis
- Concomitant tumor resistance to metastasis seen in laboratory models.
- Cancer-associated forms of the amino acid tyrosine act as anti-metastasis factors.
- Process might be manipulated chemically for therapeutic benefit.
PHILADELPHIA — Scientists are another step closer to understanding what drives tumor metastasis, as laboratory models suggest there are factors inside tumors that can slow their own growth.
In a recent issue of Cancer Research, a journal of the American Association for Cancer Research, Raúl A. Ruggiero, Ph.D., a biological researcher at the division of experimental medicine at the National Academy of Medicine in Buenos Aires, Argentina, described this novel mechanism.
Ruggiero and colleagues used bioanalytical methods of ion electrospray mass and tandem mass spectrometry to identify the factors that lead to metastasis resistance in laboratory models of localized cancer, a phenomenon called “concomitant tumor resistance” in which factors in a tumor can inhibit its own metastasis.
“The main cause of death in cancer patients is associated much more with metastasis rather than with the growth of a localized tumor, which generally can be surgically removed,” he said.
Ruggiero’s laboratory found that the presence of variant forms of the amino acid tyrosine were responsible for concomitant tumor resistance. In tumor models where these variants of tyrosine were present, the localized tumor did not tend to metastasize as fast as tumors lacking the variants.
Currently, tumor metastasis is treated with various chemotherapy regimens, but Ruggiero said the results of this sort of treatment are usually disappointing. He hopes that these tyrosine variants could be developed as a simple and safe type of therapy to retard metastatic growth.
“Both meta- and ortho-tyrosine have many attractive features. They exert antitumor effects at very low concentrations, are naturally produced in the proper tumor bearing organism, and do not appear to exert any toxic side effects,” said Ruggiero. “If these findings are confirmed we could develop new and more harmless means to manage malignant disease.”
The mission of the American Association for Cancer Research is to prevent and cure cancer. Founded in 1907, the AACR is the world’s oldest and largest professional organization dedicated to advancing cancer research. The membership includes 33,000 basic, translational and clinical researchers; health care professionals; and cancer survivors and advocates in the United States and more than 90 other countries. The AACR marshals the full spectrum of expertise from the cancer community to accelerate progress in the prevention, diagnosis and treatment of cancer through high-quality scientific and educational programs. It funds innovative, meritorious research grants, research fellowships and career development awards. The AACR Annual Meeting attracts more than 18,000 participants who share the latest discoveries and developments in the field. Special conferences throughout the year present novel data across a wide variety of topics in cancer research, treatment and patient care. The AACR publishes seven major peer-reviewed journals: Cancer Discovery; Cancer Research; Clinical Cancer Research; Cancer Epidemiology, Biomarkers & Prevention; Molecular Cancer Therapeutics; Molecular Cancer Research; and Cancer Prevention Research. AACR journals received 20 percent of the total number of citations given to oncology journals in 2010. The AACR also publishes Cancer Today, a magazine for cancer patients, survivors and their caregivers which provides practical knowledge and new hope for cancer survivors. A major goal of the AACR is to educate the general public and policymakers about the value of cancer research in improving public health, the vital importance of increases in sustained funding for cancer research, and the need for national policies that foster innovation and progress in the field.