BACKGROUND/AIMS: M2 pyruvate kinase (M2-PK) is an enzyme that is produced in undifferentiated and proliferating tissues. This study aims to evaluate the usefulness of the immunochromatographic M2 pyruvate kinase (iM2-PK) for the screening of colorectal cancer (CRC) and premalignant lesions. METHODS: Healthy volunteers and patients with colorectal neoplasia were enrolled in six academic hospitals in the capital province of Korea. The iM2-PK value was compared with the immunochromatographic fecal occult blood test (iFOBT) and fecal tumor M2-PK enzyme-linked immunosorbent assay (ELISA). RESULTS: A total of 323 subjects were enrolled. The sensitivity of iM2-PK for CRC was 92.8%, which was superior to iFOBT (47.5%, p<0.0001). For adenomatous lesions, the sensitivity of iM2-PK was 69.4%, which was also superior to iFOBT (12.1%, p<0.001). Compared with M2-PK ELISA, iM2-PK exhibited significantly enhanced sensitivity for CRC (97.5% vs 80.0%, p=0.0289). The sensitivity of iM2-PK was higher in advanced stages of CRC compared with cancers confined to the mucosa and submucosa (p<0.05). However, lymph node metastasis had no influence on the sensitivity of iM2-PK. CONCLUSIONS: The iM2-PK exhibited increased sensitivity for identifying CRC and adenomatous lesions compared with iFOBT. Given its rapid results and convenience, CRC screening using iM2-PK is promising.
Adenoma/*diagnosis ; Adult ; Aged ; Aged, 80 and over ; Biomarkers, Tumor/*analysis ; Clinical Enzyme Tests/*instrumentation ; Colorectal Neoplasms/*diagnosis ; Enzyme-Linked Immunosorbent Assay ; Feces/*enzymology ; Female ; Healthy Volunteers ; Humans ; Immunochromatography/methods ; Male ; Middle Aged ; Occult Blood ; Precancerous Conditions/diagnosis/enzymology ; Predictive Value of Tests ; Pyruvate Kinase/*analysis ; Reagent Kits, Diagnostic ; Republic of Korea ; Sensitivity and Specificity