Prediction of chemosensitivity of colorectal cancer to 5-fluorouracil by gene expression profiling with cDNA microarrays.

5-Fluorouracil (5-FU) is the most widely used anticancer agent for gastrointestinal cancers. Because many tumors show primary resistance, it is clinically meaningful to predict tumor sensitivity to the drug before treatment. cDNA microarrays containing 21,168 clones were used to identify genes associated with sensitivity to 5-FU. Gene expression profiling of 3 colorectal cancer cell lines (DLD-1, HT-29 and NUGC-3) and the corresponding 5-FU-resistant sublines (DLD-1/FU, HT-29/FU and NUGC-3/5FU/L) showed 81 genes that were differentially expressed. The gene set thus identified successfully predicted the sensitivities of 5 other colorectal cancer cell lines and could also separate 5-FU resistant clinical samples from sensitive ones.