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<0.0001), exhibited primary tumour localisation in the colon (52% vs 40% p=0.03) and had synchronous onset of metastases (70% vs 19% p<0.0001). Primary tumours of patients with hepatic metastases were more commonly T3 tumours (79% vs 63% p=0.006) and less commonly of mucinous histology (5% vs 16% p=0.02). Gain of 20p11 was more often observed in patients with hepatic metastases (p<0.05), which was confirmed in an independent dataset (p<0.05; false discovery rate