Liver-metastatic potential of colorectal cancer is related to the stromal composition of the tumour.

BACKGROUND The tumour stroma is an important modulator of cancer cell behaviour. The aim of this study was to compare the stromal composition between primary colorectal cancer (CRC) and colorectal liver metastases (CLM). MATERIALS AND METHODS The stromal composition in matched tissue sections of CRC and subsequent CLM was analysed, and related to clinical parameters. RESULTS Differences in the expression pattern of type I collagen and type IV collagen in CRC was related to a higher risk of CLM. Two types of CLM the desmoplastic and pushing type were identified. The time between CRC and diagnosis of CLM was shorter (p=0.047) for desmoplastic CLM. The mortality rate was higher for pushing CLM due to frequent extrahepatic disseminated disease. A difference in the overall survival rate between patients with desmoplastic and those with pushing CLM was seen at follow-up of more than 60 months (p=0.046). CONCLUSION The liver-metastasizing potential is related to the stromal composition of primary CRC. There are distinct growth patterns in CLM with differences in stromal composition and clinical outcome.