Distinguishing patterns of gene expression can be used to forecast response to treatment in patients with advanced metastatic colorectal cancer, report scientists from Institut de Recherche en Cancérologie de Montpellier.
They discovered an 11-gene signature that could be used to separate patients who would respond to the chemotherapy FOLFIRI (leucovorin, fluorouracil, and irinotecan) from those who would not. The test for the 11-gene signature took about three days to run and involves the surgical removal of tumor tissue, histologic validation, RNA extraction, chip hybridization, comparative analysis of gene expression, and patient classification.
The research team used microarray analysis to identify gene-expression levels in samples taken from 19 colorectal cancer patients with liver metastases who had not yet started chemotherapy. They followed the patients to see who responded to the chemotherapy.
Using this information, they found the pattern of 11 genes that clearly separated responders and from the nonresponders. They then designed a mathematical model that was able to predict and classify the eight responding and 11 nonresponding patients with 100% accuracy.
“The fact that we achieved 100% accuracy could be due to our small sample size of 19 patients,” points out Maguy Del Rio, Ph.D. “Obviously, it is essential to validate and if necessary to improved the gene signature in a larger independent cohort of patients. Until it is properly validated, the gene signature cannot be used in the clinic.”
Dr. Rio presented these results at the 20th EORTC-NCI-AACR symposium on “Molecular Targets and Cancer Therapeutics” held in Geneva.