Studies demonstrate differing response from left and right colon tumors

Significant genetic differences exist between tumors of the right and left side of the colon, according to data presented today at the 94th Annual Meeting of the American Association for Cancer Research (AACR), and these distinctions should be considered for future research and treatment.

“With emerging treatments directed toward specific molecular targets, there should be special emphasis on such an important differentiation,” said Sanne Olesen, M.Sc. of biology, Aarhus University Hospital, Denmark, and lead investigator of the study conducted by scientists from Denmark and Finland. “Hopefully with this new understanding of the differences that exist in the colon, we can more efficiently treat cancer patients.”

In the study, approximately 6,800 known genes were monitored for activity. Twenty single samples of normal colonic mucosa were compared to 25 single cancerous samples from both the left and right sides of the colon. Findings were validated by semi-quantitative, RealTime-PCR and immunohistochemistry, or observations of clinical reactions to the immune system.

Scientists found 58 genes that were dissimilar between the normal samples and the left-sided tumor samples, and 118 genes between the normal samples and the right-sided tumor samples. An additional 44 unique genes were found between the right- and left-sided tumor samples. Furthermore, scientists identified 30 genes which showed parallel expression in both sides, and therefore may be regarded as general tumor markers.

“This discovery may explain why some colorectal patients have responded to treatment while others did not,” said Dr. Torben Orntoft, a professor at Aarhus University. “With new targeted therapies in development, our patients have a better chance of survival.”

Colon cancer is one of the most common cancers found in men and women today. The American Cancer Society estimates that in 2003 there will be about 105,500 new cases of colon cancer in the United States, causing over 57,000 deaths

Founded in 1907, the American Association for Cancer Research (AACR) is a professional society of more than 20,000 laboratory and clinical scientists engaged in cancer research in the United States and more than 60 other countries. AACR’s mission is to accelerate the prevention and cure of cancer through research, education, communication and advocacy. Its principal activities include the publication of five major peer-reviewed scientific journals (Cancer Research; Clinical Cancer Research; Molecular Cancer Therapeutics; Molecular Cancer Research; and Cancer Epidemiology, Biomarkers & Prevention). AACR’s annual meeting attracts more than 12,000 participants who share new and significant discoveries in the cancer field, and the AACR’s specialty meetings throughout the year focus on all the important areas of basic, translational and clinical cancer research.

Contact: Warren Froelich/AACR
froelich@aacr.org
215/440-9300

Aimee Frank/Spectrum Science
amf@spectrumscience.com
202/955-6222

In Washington, DC: (7/11-7/14)
Washington Convention Center
202/249-4060