Correlation between Faecal Tumour M2 Pyruvate Kinase and Colonoscopy for the Detection of Adenomatous Neoplasia in a Secondary Care Cohort

The Importance of Evaluating Serum Levels of Tumor Markers M2-PK and Inhibin A in Patients Undergoing Colonoscopy

Despite the use of colonoscopy to detect colon cancer due to its aggressiveness, high cost, and lack of patient compliance, the use of laboratory tests with high accuracy and sensitivity, such as tumor marker M2-PK and Inhibin A is recommended and can be effective for early diagnosis and screening of patients in the early stages. We studied 46 patients admitted it the gastrointestinal ward of Amir al Momenin Hospital and 45 normal (age and sex-matched) subjects as a control group (case-control and retrospective studies). Before the colonoscopy, the level of tumor marker M2-PK in the stool sample and the serum level of Inhibin A were evaluated in patients and the control group. The level of tumor marker M2-PK was significantly higher in the group with hyperplastic polyps and colon cancer (P < .001) than in the control group. At the same time, there was no significant difference in Inhibin A level (P = .054). In the hyperplastic polyps group 73% and in the colorectal cancer group 27% had a positive immunochemical fecal occult blood (IFOBT) result, significantly higher than the control group (P < .001). Evaluation of the level of tumor marker M2-PK in the stool sample in association with the three-time iFOBT test method may be suggested as a quick and noninvasive method for screening and diagnosis of polyps and early stages of colon cancer.

Expression of tumor pyruvate kinase M2 isoform in plasma and stool of patients with colorectal cancer or adenomatous polyps

Background

Tumor pyruvate kinase M2 isoform (tM2-PK), which is an isoform of PK-glycolytic enzyme and appears on the surface of cancerous proliferating cells, has been used as a diagnostic biomarker for colorectal cancer (CRC). The aim of this study was to evaluate the tM2-PK measurement test for the diagnosis of CRCs and adenomatous polyps in plasma and stool samples in an Iranian population.

Methods

In this prospective study, a total of 226 stool and 178 plasma samples were received from patients referred to colonoscopy units. tM2-PK enzyme was measured using two separate ScheBo-Biotech-AG ELISA kits for stool and plasma samples.

Results

According to ROC curves, in the tumor group, at the cut-off value of 4 U/ml, the sensitivity of fecal tM2-PK test was 100% and the specificity was 68%, and in the polyp group, the sensitivity and specificity were 87 and 68%, respectively. For tumor detection in plasma specimens, a cut-off value > 25 U/ml has a sensitivity and specificity of 90.9 and 91.3%, respectively. Similarly, for polyp detection, a cut-off value > 19 U/ml has a sensitivity of 96.3% and the specificity of 85.5%.

Conclusions

Based on our results, a cut-off range of 4.8–8 U/ml and >  8 U/ml could be used to detect polyp and tumor in stool samples, respectively. Similarly, a cut-off range of 19–25 U/ml and > 25 U/ml is recommended in plasma samples, suggesting tM2-PK test as a non-invasive assay to diagnose CRC and adenomatous polyps.

Evaluation of Fecal M2PK as a Diagnostic Marker in Colorectal Cancer

BACKGROUND

Invasive colonoscopy is the gold standard for patients at risk for colorectal cancer. However, the need for non-invasive and specific markers is required.

OBJECTIVE

To evaluate the sensitivity of the glycolytic pyruvate kinase isoenzyme type M2 dimer (M2PK) as a diagnostic biomarker for colorectal cancer (CRC) and adenomatous colorectal polyps (CRP) screening.

DESIGN

Case-control.

PATIENTS

Twenty patients with CRC, 20 patients with CRP (lack criteria for colonic cancer by biopsy), and 20 normal subjects.

OUTCOME

Complete blood count (CBC), erythrocyte sedimentation rate (ESR), tumor markers: carcino embryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9), fecal occult blood test (FOBT), and fecal M2PK. Pelvic and abdominal ultrasound (US), colonoscopy, and a histopathological examination.

RESULTS

Only weight loss and cachexia were significantly associated with CRC than CRP or control groups. M2PK was the most sensitive and specific test in differentiating CRC from CRP and the control subjects (sensitivity = 75%, specificity = 100%).

LIMITATIONS

(1) The selection of cases for three well-matched groups, as to perform colonoscopy in well-prepared cases and conditions. (2) Replicates in more than 20 cases for confirmation at the expense of enrolling new patients. (3) The cost associated with tumor markers analysis.

CONCLUSION

Fecal M2PK can be used as a precolonoscopy screening test for CRC patients, and is superior to other tumor markers, and in indicating the progress of colorectal adenomas > 1 cm. Thus being cost-effective and easy-to-perform test, it is a feasible tool to preselect patients who require colonoscopy.

Value of four protein tumor markers in colorectal cancer screening

Colorectal cancer (CRC) is one of the common malignant tumors worldwide and the fourth most common cancer in China. In recent years the incidence of CRC is still on the rise. It is of great significance to carry out effective screening for CRC with regard to improving prognosis and reducing mortality. Among many screening methods currently available, the detection of tumor markers in feces and serum is easy to operate, inexpensive, and noninvasive, thus becoming the focus of research. In view of the great significance of tumor marker detection for CRC screening, this article discusses the value of four protein tumor markers in CRC screening, with an aim to provide a theoretical basis for their clinical use.