Multi-level evidence that circulating CK18 is a biomarker of tumour burden in colorectal cancer.
Citation: British Journal of Cancer, 10 2012, vol./is. 107/9(1518-24), 0007-0920;1532-1827 (2012 Oct 23)
Author(s): Greystoke A, Dean E, Saunders MP, Cummings J, Hughes A, Ranson M, Dive C, Renehan AG
Abstract: Circulating total cytokeratin 18 (tCK18) and/or caspase cleaved cytokeratin 18 (cCK18) (measured by M65 and M30 enzyme-linked immunosorbent assays (ELISAs), respectively) are used as pharmacodynamic (PD) biomarkers of epithelial cell death in clinical trials. Having validated these ELISAs, we assessed their utility in colorectal cancer (CRC).METHODS: We applied the assays in several settings: 53 controls; 97 patients undergoing surgery and 74 patients with metastatic CRC undergoing chemotherapy (55 first line; 56 patients with repeated sampling through chemotherapy). Prognostic significance was evaluated using Kaplan-Meier life tables and Cox models; PD utility was assessed by analysis of repeated measures.RESULTS: Median cCK18 and tCK18 levels were elevated in patients with cancer (both P=0.0001), and among cancer patients, there were increasing trends from early to advanced stages (both P(trends)=0.0001). Increasing tCK18 predicted for reduced survival after surgery with curative intent (adjusted hazard ratio (HR) for doubling in concentration 1.77, 95% CI: 1.04, 3.01) and after first-line chemotherapy in metastatic disease (adjusted HR per doubling in concentration=1.78, 95% CI: 1.37, 2.30). In patients with progressive disease during chemotherapy, repeated sampling revealed profiles with high baselines and progressive upwardly increases after cycle 1.CONCLUSION: This study provides evidence for cytokeratin 18 (CK18) as a prognostic and PD biomarker in patients with CRC and supports continued deployment of circulating CK18 in biomarker-enhanced trials.
Publication type: Journal Article,Research Support, Non-U.S. Gov’t