Quantitative ELISA Stool Test Screens for Colorectal Cancer

The M2 pyruvate kinase (M2-PK) is an isoenzyme of pyruvate kinase mainly produced in undifferentiated and proliferating tissues and in cancer cells and M2-PK regulates the synthetic balance between adenosine triphosphate and macromolecules.

Scientists at the Catholic University of Korea (Seoul, Korea) and their colleagues investigated the enzymatic biomarker M2-PK with volunteers in patient groups with 139 cases of colorectal cancer and 124 with adenoma, along with a population-based control group of 60 people, making a total of 323 subjects. The stool samples were collected from subjects awaiting surgery, out-patients and patients of health promotion clinics. All stool samples were collected before oral colonoscopy preparation administration and some were tested immediately, while others were stored at -20 °C.

An immunochromatographic fecal occult blood test (iFOBT), the Asan Easy Test FOB (Asan Biotech Institute, Seoul, Korea) was compared with the immunochromatographic fecal tumor M2-PK test (iM2-PK, M2-PK Quick; ScheBo Biotech AG, Giessen, Germany) and the enzyme-linked immunoassay kit Tumor M2-PKTM ELISA Stool Test also manufactured by ScheBo Biotech AG.

The sensitivity of the M2-PK test was 92.8% for colorectal cancer and 69.4% for adenomas. In addition, they also compared the results of the M2-PK test with those of an immunological fecal occult blood test (iFOBT). This was clearly inferior to the M2-PK test. The iFOBT detected only 47.5% of the colon cancers and just 12.1% of the adenomas. Consequently, the M2-PK test detected twice as many colorectal cancer cases and nearly six times the number of adenomas than the immunological fecal occult blood test (iFOBT).

The iM2-PK is an immunochromatographic qualitative method for fecal tumor M2-PK. This test is performed in about 15 minutes and the cost is about half of the fecal tumor M2-PK ELISA test. The main advantage of the iM2-PK is that it is quickly performed with fresh stool samples in clinics without being sent to a laboratory. The sensitivity of the iM2-PK was superior to that of the fecal tumor M2-PK ELISA test. The authors concluded that the iM2-PK may be a reliable and acceptable screening method for CRC. The study was published on December 5, 2014, in the journal Gut and Liver.

Related Links:
Catholic University of Korea
Asan Biotech Institute 
ScheBo Biotech AG