CRP Present within Colorectal Cancer Cells is Taken Up from the Circulation and not Produced by the Tumour; Evidence of a Complex Relationship Between Host and Tumour

AIM: Preoperative raised serum CRP (sCRP) is now widely accepted as being an independent predictor of poor survival. Although CRP is known to made by the liver, whether the tumour is a site of CRP production remains unknown. The aim if this study was to determine, in colorectal cancer, if the tumour or liver is responsible for CRP production and what is the relationship between tumoural CRP and survival. MATERIALS AND METHODS: To establish if the tumour produces CRP, reverse transcriptase PCR for CRP mRNA expression was performed on 30 malignant colorectal specimens, 19 non-malignant colorectal specimens from the resection margin and 30 healthy liver specimens from patients with no radiological evidence of liver metastasis. Tumour protein expression of CRP was assessed in a cohort of 147 parraffin embedded colorectal tumours. RESULTS: This study demonstrates that colorectal tumours are not a site of CRP production. Tumours do however, express CRP and high cytoplasmic CRP was associated with necrosis (P=0.028) and high nuclear CRP was associated with increasing T-stage (P=0.022). Tumoural CRP was not associated with disease free or cancer-specific survival. CONCLUSION: This study suggests that despite colorectal tumours expressing CRP, there is no evidence of CRP production at this site. Understanding the mechanism whereby CRP enters the cancer cells may offer a novel therapeutic target for patients presenting with a systemic inflammatory response.