The PPARγ K422Q mutation does not contribute to troglitazone inefficiency in colon cancer treatment

Peroxisome proliferator-activated receptor γ (PPARγ) ligands inhibit cell growth of colorectal cancer cells in most experimental models, but no significant effect could be observed in patients with colorectal cancer. We therefore, screened human colorectal tumors to determine the prevalence of the PPARγ K422Q loss-of-function mutation, recently identified in 50% of colonic cancer cell lines. A sensitive allele-specific real-time amplification assay was developed and 170 colorectal primary tumors and 12 liver metastasis were analyzed. We did not find the K422Q mutation in any of these samples. We can therefore exclude this alteration as a mechanism of resistance to PPARγ ligands in patients with colon cancer.