The study looked at 62 patients over the course of 10 years and uncovered the connection between dMMR’s hereditary basis in rectal cancer. This new information is expected to help physicians with diagnosis, treatment and preventive measures, according to the study, which was published in the Journal of Clinical Oncology’s July 18 online issue.
“Four genes — MLH1, MSH2, MSH6 and PMS2 — previously have been associated with DNA mismatch repair,” an MD Anderson Cancer Center news release stated. “Until now, researchers believed MLH1 and MSH2 were the main culprits causing the DNA repair machinery to break down. The MD Anderson study found MSH2 and MSH6 to be most commonly found among dMMR rectal cancer patients.”
Last year, President Obama launched the Precision Medicine Initiative, earmarking millions of dollars for medical research. “Precision medicine is an emerging approach for disease treatment and prevention that takes into account individual variability in genes, environment and lifestyle for each person,” according to the PMI website.
The MD Anderson Cancer Center news release stated that “precision medicine encourages therapeutic options tailored to specific characteristics such as a person’s genetic makeup or the genetic profile of an individual’s tumor.”
In the study, associate professor of surgical oncology Y. Nancy You, MD, explained how precision medicine improves treatment options for colorectal patients. “This new genetic understanding of dMMR provides immediate implications for telling patients how well they will do long term and for choosing the best surgical and chemotherapy options,” she said. “If we know a patient carries this mutation, then we can enroll them in our Familial High-Risk GI Cancer Clinic, where we follow them and their at-risk family members and conduct cancer surveillance tests to detect precancerous lesions and remove them as early as we can.”
Excluding skin cancers, the American Cancer Society lists colorectal cancer as the third most common cancer diagnosis in both men and women in the U.S., with 95,270 new cases of colon cancer this year and 39,220 new cases of rectal cancer.
Colorectal cancer is expected to cause about 49,000 deaths this year alone, the American Cancer Society website stated. However, treatments continue to improve and those numbers are lowering due to screenings and early diagnosis. The website states there are more than one million people in the U.S. who are colorectal cancer survivors.
The Precision Medicine Initiative is providing $215 million this year to support medical research, according to the National Institutes for Health website. “Of this proposed budget, $130 million was allocated to NIH to build a national, large-scale research participant group, called a cohort, and $70 million was allocated to the National Cancer Institute to lead efforts in cancer genomics as part of PMI for Oncology.”
The MD Anderson Cancer Center is studying several hereditary cancer syndromes including but not limited to HBOC (Hereditary Breast and Ovarian Cancer), Li-Fraumeni, and Lynch, the latter of which causes early age onset colorectal and endometrial cancers and extracolonic tumors.
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For more information, read the CE module “Progress Made Against Colorectal Cancer.”