Faecal dimeric M2 pyruvate kinase in colorectal cancer and polyps correlates with tumour staging and surgical intervention

Abstract

Objective and method: A dimeric form of pyruvate kinase isoenzyme (tumour M2-PK) is predominantly found in highly proliferating cells. Sandwich ELISA with monoclonal antibodies against dimeric (tumour) M2-PK was used to measure faecal tumour M2-PK in; 13 controls, 10 patients with colonic polyps and 32 patients with colorectal cancer. Results: Levels of faecal tumour M2-PK were higher in patients with colorectal cancer (median 11.72U/ml; range 0.9 - 146.95U/ml, P = 0.0001) and polyps greater than 10mm (median 2.54U/ml; range 0.9 - 29.46U/ml, P = 0.041) when compared with controls (median 1.75U/ml; range 0.9 - 3.41U/ml). Furthermore, levels were higher in stages Duke's B (P = 0.013) and Duke's C (P = 0.43) than in Duke's A. Six months postsurgery faecal tumour M2-PK levels fell significantly to 3.46U/ml (range 1.03 - 9.05U/ ml, P = 0.001). The sensitivity of a positive faecal tumour M2-PK test, defined as a level above 3.33U/ml, was 91% for colorectal cancer, 60% for >10mm and 20% for <10mm polyps, with a specificity of 92%. Conclusion: Faecal tumour M2-PK is a highly sensitive marker for colorectal cancer and larger polyps. It also correlates with more advanced stages of colorectal cancer and its reduction is associated with successful surgical intervention. © 2008 The Authors. Journal compliation © 2008 The Association of Coloproctology of Great Britain and Ireland.