June 5, 2000
John Carethers, M.D., assistant professor of medicine at UCSD School of Medicine and member of the UCSD Cancer Center, received the highest score possible in the granting process. There were 92 grants funded out of 302 applications submitted.With this grant, Carethers and colleagues will study tissue samples from African-American colon cancer patients to determine the incidence and impact of a particular chromosomal abnormality, called microsatellite instability (MSI). This abnormality is associated with colorectal cancer development, particularly the more virulent types. African-Americans seem to suffer from a more aggressive form of the disease compared to whites.
“When compared to statistics for whites, African-Americans have only a slightly higher incidence of colorectal cancer, but they have much higher death rates,” said Carethers. “We believe MSI may play an important role.”
Preliminary research in Carethers’ laboratory has shown that cells with this abnormality do not respond to the widely used chemotherapeutic agent 5-fluoruracil (5-FU). The researchers will now further test this observation by studying the medical records of patients who received 5-FU treatment and whose tissue tested positive for microsatellite instability.
Also, the team will study the genes mutated by microsatellite instability to determine if they might be useful in predicting a given tumor’s potential for metastasis.
“The new insights gained from this work may reveal the need for new screening strategies and new chemotherapeutic agents,” said Carethers. “In addition, we hope to gain a clearer understanding of tumor formation that will benefit all patients.”Every year, approximately 149,000 people in the U.S. are diagnosed with colorectal cancer and about 56,000 people die of the disease. It is the second most common cause of cancer death in the U.S.
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