Chromosome 20p11 gains are associated with liver-specific metastasis in patients with colorectal cancer

Objective Metastatic colorectal cancer (CRC) cells have a selective preference for certain target organs that cannot be explained by circulatory patterns alone. This study aimed to identify clinicopathological features and chromosomal aberrations of primary tumours associated with organ-specific CRC metastasis. Design Clinicopathological features were investigated in patients with CRC who had exclusively hepatic (n=182) versus exclusively extrahepatic (n=139) metastases. A total of 139 primary tumours of patients with hepatic (n=85) and extrahepatic metastases (n=54) were screened for chromosomal aberrations by microarray-based comparative genomic hybridisation, and the findings were validated in an independent set of 80 primary tumours. A publicly available database was used to correlate chromosomal aberrations with gene expression. Protein expression was evaluated by immunohistochemistry on tissue microarrays. Results Patients with hepatic metastases were significantly more often male (71% vs 53% p=0.002), more often had abnormal lactate dehydrogenase activity (37% vs 14% p C20orf3 showed the strongest correlation between RNA expression and DNA copy number. This was reflected in significantly higher protein expression in patients with hepatic metastases (59%; n=325) than in those with extrahepatic metastases (41%; n=256) (p=0.01). Conclusion C20orf3 mapping at 20p11 is associated with hepatic-specific metastasis in patients with CRC. This gene is a candidate biomarker for liver metastases and may be of clinical value in early-stage CRC.