Gene expression profiling of colorectal cancer and metastases divides tumours according to their clinicopathological stage.

Gene expression profiling of matched colorectal carcinomas and metastases could reveal key molecular events involved in tumour progression and metastasis. Expression profiles have been created from 25 colorectal carcinomas (CRCs, pT1-4), corresponding normal colonic mucosa, and 14 liver metastases using cDNA arrays containing 1176 cancer-related genes (Clontech). Hierarchical clustering clearly distinguished carcinomas from non-cancerous tissues, separated tumours into high-stage (pT4 and extensive lymph node or distant metastases) and low-stage (< or =pT3) groups, and correlated with the histopathological classification in 87% (33/38 cases).