Pyruvate Kinase M (PKM) binds ribosomes in a poly-ADP ribosylation dependent manner to induce translational stalling.

In light of the numerous studies identifying post-transcriptional regulators on the surface of the endoplasmic reticulum (ER), we asked whether there are factors that regulate compartment specific mRNA translation in human cells. Using a proteomic survey of spatially regulated polysome interacting proteins, we identified the glycolytic enzyme Pyruvate Kinase M (PKM) as a cytosolic (i.e. ER-excluded) polysome interactor and investigated how it influences mRNA translation. We discovered that the PKM-polysome interaction is directly regulated by ADP levels-providing a link between carbohydrate metabolism and mRNA translation. By performing enhanced crosslinking immunoprecipitation-sequencing (eCLIP-seq), we found that PKM crosslinks to mRNA sequences that are immediately downstream of regions that encode lysine- and glutamate-enriched tracts. Using ribosome footprint protection sequencing, we found that PKM binding to ribosomes causes translational stalling near lysine and glutamate encoding sequences. Lastly, we observed that PKM recruitment to polysomes is dependent on poly-ADP ribosylation activity (PARylation)-and may depend on co-translational PARylation of lysine and glutamate residues of nascent polypeptide chains. Overall, our study uncovers a novel role for PKM in post-transcriptional gene regulation, linking cellular metabolism and mRNA translation.

Comparison of faecal protein biomarkers' diagnostic accuracy for colorectal advanced neoplasms: a systematic review and meta-analysis.

Early diagnosis of colorectal advanced neoplasms (ANs), including colorectal cancer (CRC) and advanced adenoma (AA), has a positive effect on the survival rate. As a first attempt, the aim of this meta-analysis was to compare the diagnostic accuracy of faecal protein biomarkers for the detection of colorectal neoplasms with consideration of a wide range of covariates. A systematic literature search was performed up to Jun 10, 2021 on Web of Sciences, Scopus and PubMed. The diagnostic accuracies were calculated using the bivariate/hierarchical random effect model. Biomarkers were determined to be clinically applicable (CA) if they had areas under the curve > 0.70 and positive and negative likelihood ratios > 2 and < 0.5, respectively. A total of 47,059 test results were extracted from 16 immunochemical faecal occult blood test (iFOBT), 26 pyruvate kinase-M2 (PK-M2) and 23 faecal calprotectin (FC) studies. Only iFOBT, PK-M2 and FC for CRC plus iFOBT and PK-M2 for AN were CA. iFOBT had significantly superior accuracy (P = 0.02 versus PK-M2 and P < 0.01 versus FC for CRC; P < 0.01 versus PK-M2 for AN). Regarding covariates, the lateral flow method of PK-M2 measurement increased its accuracy for CRC detection compared to the enzyme-linked immunosorbent assay (P < 0.01). iFOBT is recommended as the most accurate faecal biomarker for CRC and AN diagnosis.

Faecal biomarkers do not always identify pre-cancerous lesions in patients who present in primary care with bowel symptoms.

AIM: To determine if tumour-derived M2-PK is potentially a more accurate biomarker of pre-cancerous bowel lesions in patients who present in primary care with bowel symptoms than the detection of faecal haemoglobin. METHODS: Patients requested by their general practitioners (GPs) to provide a stool sample to determine the presence of faecal haemoglobin consented for the same stool samples to be tested for the presence of M2-PK. For comparison M2-PK levels were also measured in stool samples from patients recently identified with colorectal cancer and healthy controls who self-reported no bowel problems at the time of sampling. RESULTS: M2-PK levels measured in 185 GP-derived samples were comparable to the control cohort (57 healthy controls) and notably lower than those in the 57 patients with CRC (2.6, 3.2 and 18.2U/ml-1, respectively). Sixty-seven of the GP patients were referred for colonoscopy. While 26 of these patients had a positive M2-PK, only 10 were found to have colonic lesions. Conversely, 18 of the 41 patients who had a negative M2-PK were found to have lesions that included one CRC, 13 adenomas and four other polyps. The FIT also failed to identify colonic disease in 19 of 48 patients referred for colonoscopy. There was, however, a significant association between lesions greater than 1cm and a positive FIT (p<0.02) that was not the case with M2-PK. A positive FIT identified one patient in the GP patient cohort subsequently diagnosed with colorectal cancer at follow-up colonoscopy whereas the same stool sample tested negative for M2-PK. CONCLUSIONS: Measurement of faecal M2-PK levels lacks the specificity and sensitivity (and therefore diagnostic accuracy) to identify the individuals who should be progressed for clinical follow-up. Accordingly, M2-PK is not is not a robust biomarker for identifying pre-cancerous bowel lesions in a primary care setting.

Examination of the temporal variation of peptide content in decomposition fluid under controlled conditions using pigs as human substitutes.

We report the preliminary observations of the peptide content of decomposition fluid produced under controlled laboratory conditions and in the absence of a soil matrix. Four domestic pig (Sus scrofa domesticus) cadavers were used to model human decomposition over a four-week trial period; physical characteristics were recorded and the peptide components of decomposition fluid was analysed using high performance liquid chromatography-time of flight mass spectrometry. Preliminary data analysis indicated that a range of peptides were consistently detected across the course of the trial period and 27 of these were common to all four cadavers; 22 originating from haemoglobin. The peptides associated with haemoglobin subunit alpha and beta displayed a breakdown pattern that remained consistent for all cadavers for the duration of the trial. Though identification of peptides during decomposition has potential for estimating the time since death, quantification of selected peptides is likely to be essential to identify time-dependent trends.

Effects of bovine enterovirus and type 1 diabetes on liver and kidney pyruvate kinase activity in an animal model

Type 1 diabetes (T1D) is an autoimmune disease characterized by the selective destruction of pancreatic beta cells. In addition to genetic factors, enteroviruses have been considered the main environmental factor involved in this pathology. Therefore, the objective of this study was to evaluate the effects of streptozotocin-induced diabetes and bovine enterovirus (BEV) on liver and kidney pyruvate kinase activity in rats. Fourteen male Wistar rats were divided in three groups: control, diabetes and a third group, which was fed with water experimentally contaminated by BEV. Increased blood glucose levels were found in both diabetes and enterovirus groups, whereas there were no alterations in the lipid profile. A reduced pyruvate kinase activity was observed in the liver and kidney of animals from diabetes and enterovirus groups. Under our experimental conditions, the ingestion of water experimentally contaminated by BEV induced alterations in glycaemia, and also interfered in the pyruvate kinase activity in liver and kidney of the rats, which might be one of the possible mechanisms involved in the T1D development.

The Multifarious Functions of Pyruvate Kinase M2 in Oral Cancer Cells.

Head and neck cancers, including oral squamous cell carcinoma (OSCC), are the sixth most common malignancies worldwide. OSCC frequently leads to oral dysfunction, which worsens a patient's quality of life. Moreover, its prognosis remains poor. Unlike normal cells, tumor cells preferentially metabolize glucose by aerobic glycolysis. Pyruvate kinase (PK) catalyzes the final step in glycolysis, and the transition from PKM1 to PKM2 is observed in many cancer cells. However, little is known about PKM expression and function in OSCC. In this study, we investigated the expression of PKM in OSCC specimens and performed a functional analysis of human OSCC cells. We found that the PKM2/PKM1 ratio was higher in OSCC cells than in adjacent normal mucosal cells and in samples obtained from dysplasia patients. Furthermore, PKM2 expression was strongly correlated with OSCC tumor progression on immunohistochemistry. PKM2 expression was higher during cell growth, invasion, and apoptosis in HSC3 cells, which show a high energy flow and whose metabolism depends on aerobic glycolysis and oxidative phosphorylation. PKM2 expression was also associated with the production of reactive oxygen species (ROS) and integration of glutamine into lactate. Our results suggested that PKM2 has a variety of tumor progressive functions in OSCC cells.

Thiol/disulfide status regulates the activity of thiol-containing kinases related to energy homeostasis in rat kidney.

Considering that thiol-containing enzymes like kinases are critical for several metabolic pathways and energy homeostasis, we investigated the effects of cystine dimethyl ester and/or cysteamine administration on kinases crucial for energy metabolism in the kidney of Wistar rats. Animals were injected twice a day with 1.6 µmol/g body weight cystine dimethyl ester and/or 0.26 µmol/g body weight cysteamine from the 16th to the 20th postpartum day and euthanized after 12 hours. Pyruvate kinase, adenylate kinase, creatine kinase activities and thiol/disulfide ratio were determined. Cystine dimethyl ester administration reduced thiol/disulfide ratio and inhibited the kinases activities. Cysteamine administration increased the thiol/disulfide ratio and co-administration with cystine dimethyl ester prevented the inhibition of the enzymes. Regression between the thiol/disulfide ratio, and the kinases activities were significant. These results suggest that redox status may regulate energy metabolism in the rat kidney. If thiol-containing enzymes inhibition and oxidative stress occur in patients with cystinosis, it is possible that lysosomal cystine depletion may not be the only beneficial effect of cysteamine administration, but also its antioxidant and thiol-protector effect.

Age-related levels of fecal M2-pyruvate kinase in children with cystic fibrosis and healthy children 0 to 10years old.

BACKGROUND: The pathogenesis of gut inflammation, bacterial dysbiosis and increased rates of malignancy in CF is unclear. Fecal M2-pyruvate kinase (M2-PK) is a biomarker indicative of cellular proliferation that may be raised in intestinal malignancy and inflammation. Biomarkers, including M2-PK, may be useful in assessing effects of novel therapies on the gastrointestinal tract. METHODS: M2-PK was measured in stools collected from patients with CF and HC (0-10years). Linear mixed model analysis was used. RESULTS: M2-PK levels did not significantly change in children with CF (36 patients, 77 samples) (P=0.998) or HC (45 patients, 45 samples) (P=0.21), over the age range 0-10years. Patients with CF had elevated M2-PK compared to HC (median [IQR; range]: 10.7 [5.7-28.6; 1.0-239.1] (n=77) vs. 1.0 [1.0-1.0; 1.0-50.0] (n=45) U/mL, respectively; P=0.001). CONCLUSIONS: Fecal M2-PK was elevated in children with CF compared with HC during infancy and throughout childhood suggesting abnormalities in the CF gut exist in early life.

Ultra-performance liquid chromatography-tandem mass spectrometry-based multiplex enzyme assay for six enzymes associated with hereditary hemolytic anemia.

Deficiencies in erythrocyte metabolic enzymes are associated with hereditary hemolytic anemia. Here, we report the development of a novel multiplex enzyme assay for six major enzymes, namely glucose-6-phosphate dehydrogenase, pyruvate kinase, pyrimidine 5'-nucleotidase, hexokinase, triosephosphate isomerase, and adenosine deaminase, deficiencies in which are implicated in erythrocyte enzymopathies. To overcome the drawbacks of traditional spectrophotometric enzyme assays, the present assay was based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The products of the six enzymes were directly measured by using ion pairing UPLC-MS/MS, and the precision, linearity, ion suppression, optimal sample amounts, and incubation times were evaluated. Eighty-three normal individuals and 13 patients with suspected enzymopathy were analyzed. The UPLC running time was within 5min. No ion suppression was observed at the retention time for the products or internal standards. We selected an optimal dilution factor and incubation time for each enzyme system. The intra- and inter-assay imprecision values (CVs) were 2.5-12.1% and 2.9-14.3%, respectively. The linearity of each system was good, with R2 values >0.97. Patient samples showed consistently lower enzyme activities than those from normal individuals. The present ion paring UPLC-MS/MS assay enables facile and reproducible multiplex evaluation of the activity of enzymes implicated in enzymopathy-associated hemolytic anemia.

Power of screening tests for colorectal cancer enhanced by high levels of M2-PK in addition to FOBT.

Colorectal cancer (CRC) is a multistep process that involves adenoma-carcinoma sequence. CRC can be prevented by routine screening, which can detect precancerous lesions. The aim of this study is to clarify whether faecal occult blood test (i-FOBT), tumor M2 pyruvate kinase (t-M2-PK), and endocannabinoid system molecules (cannabinoid receptors type 1-CB1, type 2-CB2, and fatty acid amide hydrolase-FAAH) might represent better diagnostic tools, alone or in combination, for an early diagnosis of CRC. An immunochemical FOB test (i-FOBT) and quantitative ELISA stool test for t-M2-PK were performed in 127 consecutive patients during a 12 month period. Endocannabinoid system molecules and t-M2-PK expression were detected by immunostaining in healthy tissues and normal mucosa surrounding adenomatous and cancerous colon lesions. i-FOBT and t-M2-PK combination leads to a better diagnostic accuracy for pre-neoplastic and neoplastic colon lesions. T-M2-PK quantification in stool samples and in biopsy samples (immunostaining) correlates with tumourigenesis stages. CB1 and CB2 are well expressed in healthy tissues, and their expression decreases in the presence of advanced stages of carcinogenesis and disappears in CRC. FAAH signal is well expressed in normal mucosa and low-risk adenoma, and increased in high-risk adenoma and carcinoma adjacent tissues. This study shows that high levels of t-M2-PK in addition to FOBT enhance the power of a CRC screening test. Endocannabinoid system molecule expression correlates with colon carcinogenesis stages. Developing future faecal tests for their quantification must be undertaken to obtain a more accurate early non-invasive diagnosis for CRC.

Accurate cut-offs for predicting endoscopic activity and mucosal healing in Crohn's disease with fecal calprotectin.

BACKGROUND: Fecal biomarkers, especially fecal calprotectin, are useful for predicting endoscopic activity in Crohn's disease; however, the cut-off point remains unclear. The aim of this paper was to analyze whether faecal calprotectin and M2 pyruvate kinase are good tools for generating highly accurate scores for the prediction of the state of endoscopic activity and mucosal healing. METHODS: The simple endoscopic score for Crohn's disease and the Crohn's disease activity index was calculated for 71 patients diagnosed with Crohn's. Fecal calprotectin and M2-PK were measured by the enzyme-linked immunosorbent assay test. RESULTS: A fecal calprotectin cut-off concentration of ≥ 170 µg/g (sensitivity 77.6%, specificity 95.5% and likelihood ratio +17.06) predicts a high probability of endoscopic activity, and a fecal calprotectin cut-off of ≤ 71 µg/g (sensitivity 95.9%, specificity 52.3% and likelihood ratio -0.08) predicts a high probability of mucosal healing. Three clinical groups were identified according to the data obtained: endoscopic activity (calprotectin ≥ 170), mucosal healing (calprotectin ≤ 71) and uncertainty (71 > calprotectin < 170), with significant differences in endoscopic values (F = 26.407, p < 0.01). Clinical activity or remission modified the probabilities of presenting endoscopic activity (100% vs 89%) or mucosal healing (75% vs 87%) in the diagnostic scores generated. M2-PK was insufficiently accurate to determine scores. CONCLUSIONS: The highly accurate scores for fecal calprotectin provide a useful tool for interpreting the probabilities of presenting endoscopic activity or mucosal healing, and are valuable in the specific clinical context.

Diagnostic Accuracy of Five Different Fecal Markers for the Detection of Precancerous and Cancerous Lesions of the Colorectum.

Background. Colorectal cancer (CRC) is the second deadliest malignancy worldwide. This study aimed to compare the diagnostic accuracy of different fecal markers in the detection of colorectal adenomas and cancer. Methods. Stool samples of patients referred to colonoscopy were collected for the analysis of tumor M2 pyruvate kinase (M2PK), human hemoglobin (Hb), hemoglobin/haptoglobin (Hb/Hp) complex, fecal calprotectin (FC), and matrix metalloproteinase-9 (MMP-9). Results. Sensitivity and specificity of M2PK for adenomas sized > 1 cm were 60% and 67.5% and for CRC were 94.7% and 67.5%. Sensitivity and specificity of iFOBT for adenomas sized ≥ 1 cm were 80% and 72.5% and for CRC were 94.7% and 72.5%. Sensitivity and specificity of Hb/Hp complex for adenomas sized ≥ 1 cm were 80% and 52.9% and for CRC were 100% and 52.9%. Sensitivity of FC and MMP-9 for CRC was 77.8% and 72.2%. Combined use of M2PK, iFOBT, and FC resulted in a sensitivity and specificity of 95% and 47.5% for the detection of adenomas sized ≥ 1 cm. Discussion. In CRC, sensitivity of M2PK, iFOBT, and Hb/Hp complex proved to be high. Combined use of M2PK, iFOBT, and FC may be valuable in the detection of large adenomas.

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

BACKGROUND AND AIMS: Colorectal cancer screening programmes that target detection and excision of adenomatous colonic polyps have been shown to reduce colorectal cancer related mortality. Many screening programmes include an initial faecal occult blood test (FOBt) prior to colonoscopy. To refine the selection of patients for colonoscopy other faecal-based diagnostic tools have been proposed, including tumour M2-pyruvate kinase (tM2-PK). To determine whether tM2-PK quantification may have a role in diverse settings we have assessed the assay in a cohort of patients derived from both the England bowel cancer screening programme (BCSP) and symptomatic individuals presenting to secondary care. METHOD: Patients undergoing colonoscopy provided faecal samples prior to bowel preparation. Faecal tM2-PK concentrations were measured by ELISA. Sensitivity, specificity, positive predictive value, negative predictive value and ROC analyses were calculated. RESULTS: Ninety-six patients returned faecal samples: 50 of these with adenomas and 7 with cancer. Median age was 68. Median faecal tM2-PK concentration was 3.8 U/mL for individuals without neoplastic findings at colonoscopy, 7.7 U/mL in those with adenomas and 24.4 U/mL in subjects with colorectal cancer (both, p=0.01). ROC analysis demonstrated an AUROC of 0.66 (sensitivity 72.4%, specificity 48.7%, positive predictive value 67.7%, negative predictive value 36.7%). Amongst BCSP patients with a prior positive FOBt faecal tM2-PK was more abundant (median 6.4 U/mL, p=0.03) and its diagnostic accuracy was greater (AUROC 0.82). CONCLUSION: Our findings confirm that faecal tM2-PK ELISA may have utility as an adjunct to FOBt in a screening context, but do not support its use in symptomatic patients.

Expression of pyruvate kinase M2 in human colorectal cancer and its prognostic value.

Reprogrammed metabolism is a hallmark of cancer cells. Pyruvate kinase isozyme type M2 (PKM2), which is frequently up-regulated in multiple human malignancies, has been demonstrated to play a critical function in glucose metabolism, gene transcription and tumorigenesis. However, limited knowledge is known about the expression pattern and prognostic value of PKM2 in colorectal cancer (CRC). In this study, we first observed that the mRNA level of PKM2 is commonly up-regulated in CRC tissues compared with their normal counterparts as demonstrated by data derived from Oncomine database. Similar results were also found in 32 paired CRC tumor and non-tumor specimens in our cohort and 4 CRC cell lines. Furthermore, by a large scale of immunohistochemical analysis in a tissue microarray containing 345 cases of CRC specimens, we demonstrated that the protein expression of PKM2 expression is up-regulated in 79.4% (274/345) samples detected and elevated PKM2 expression is closely correlated with enhanced TNM stage and higher serum CEA level. Meanwhile, Kaplan-Meier survival analysis showed that CRC patients with a higher PKM2 expression have a poorer clinical outcome than those with a lower PKM2 expression. Multivariate Cox regression analysis revealed that PKM2 and TNM stage are two independent prognostic factors for overall survival rate of CRC patients. Taken together, our studies reveal the prognostic value of PKM2 in CRC and support that PKM2 may act as a molecular target for CRC treatment.

Fecal pyruvate kinase is not suitable for discrimination between inflammatory bowel disease exacerbation and acute gastroenteritis.

INTRODUCTION: In inflammatory bowel diseases (IBD) diarrhea can be caused by exacerbation and/or infectious agents. Fecal calprotectin (FC) is a well-established biomarker of intestinal inflammation in IBD. However, its usefulness in depiction of IBD exacerbation from infectious diarrhea is limited. The value of fecal pyruvate kinase isoenzyme type 2 (M2-PK) in this application remains unknown. AIM: To compare the performance of M2-PK and FC in discriminating between diarrhea caused by IBD and infectious agents. MATERIALS AND METHODS: One hundred three patients were enrolled for the study, including 32 with ulcerative colitis (UC), 21 with Crohn's disease (CD), 29 with acute diarrhea caused by rotavirus (AD-RV), and 21 with acute diarrhea caused by Salmonella enteritidis (AD-SE). M2-PK and FC were measured using ELISA. Areas under receiver operating characteristic curves (AUCs), sensitivities and specificities for both tests in distinguishing between patient subgroups with moderate to severe UC and CD from AD-RV and AD-SE were calculated. RESULTS: Differences in AUCs between M2-PK and FC for distinguishing UC [CD] from AD-RV were -0.06 (p < 0.028) [-0.10 (p < 0.0018)] and for differentiating UC [CD] from AD-SE were 0.03 (NS) [-0.19(p < 0.0011)].M2-PK sensitivities and specificities in distinguishing UC [CD] from AD-RV were 75.0%[71.4%] and 89.7% [89.7%] and for differentiation of UC [CD] from AD-SE were 56.3% [71.4%] and 95.2[57.1%]. CONCLUSIONS: The performance of M2-PK in distinguishing between children with moderate-to-severe IBD and patients with infectious gastroenteritis was inferior to FC. Neither test had sensitivity ands pecificity sufficient for everyday clinical application.

A systematic review and meta-analysis of the diagnostic accuracy of pyruvate kinase M2 isoenzymatic assay in diagnosing colorectal cancer.

BACKGROUND: Screening programmes exist in many countries for colorectal cancer. In recent years, there has been a drive for a non-invasive screening marker of higher sensitivity and specificity. Stool-based pyruvate kinase isoenzyme M2 (M2-PK) is one such biomarker under investigation. The aim of this systematic review and meta-analysis is to determine the diagnostic accuracy, sensitivity and specificity of M2-PK as a screening tool in colorectal cancer. METHODS: A literature search of Ovid Medline, EMBASE and Google Scholar was carried out. The search strategy was restricted to human subjects and studies published in English. Data on sensitivity and specificity were extracted and pooled. Statistical analysis was conducted using summary receiver operating characteristic (SROC) curve methodology. RESULTS: A total of eight studies were suitable for data synthesis and analysis. Our analysis showed a pooled sensitivity and specificity for M2-PK to be 79% (CI 73%-83%) and 80% (CI 73%-86%), respectively. The accuracy of M2-PK was 0.85(0.82-0.88). CONCLUSION: Faecal M2-PK assay has a relatively good sensitivity and specificity and high accuracy for screening colorectal cancer.

Comparative effectiveness of pyruvate kinase M2 in bile, serum carbohydrate antigen 19-9, and biliary brushings in diagnosing malignant biliary strictures.

BACKGROUND: The role of M2-PK (pyruvate kinase) in bile has not been studied in comparison with brushings and carbohydrate antigen (CA) 19-9 in the diagnosis of malignant biliary strictures. AIM: To compare the diagnostic accuracy of biliary M2-PK with cytology and serum CA 19-9 METHODS: In this prospective cross-sectional study, bile was aspirated in 74 patients (discovery and validation cohort) undergoing endoscopic retrograde cholangiopancreatography. Levels of M2-PK were measured in bile and compared to brushings for cytology and CA 19-9. RESULTS: In the discovery cohort, the median bile M2-PK levels were significantly elevated in patients with malignant biliary strictures [187.9 U/l (interquartile range (IQR) 3.5, 3626.8)] compared to those with benign biliary conditions and primary sclerosing cholangitis [0 U/l (IQR 0, 15)] (P = 0.007). A M2-PK cutoff value of 109.1 U/l distinguished malignant from benign conditions with a sensitivity and specificity of 52.9 and 94.1 %, respectively, and area under curve (AUC) of 0.77. The sensitivity of CA 19-9 and brushings in diagnosing cancer was 52.9 % and 11.1 % and specificity 94.1 and 100 %, respectively. The presence of elevated M2-PK >109.1 U/l or CA 19-9 >33 U/ml or positive brushing was 88.2 % sensitive and 88.2 % specific, AUC of 0.89 in the diagnosis of malignancy. The diagnostic accuracy was confirmed in the validation cohort. CONCLUSIONS: As a stand-alone factor, none of the markers were able to distinguish benign from malignant biliary strictures with a high sensitivity. However, a combination was highly sensitive in diagnosing malignant biliary strictures.

The Usefulness of a Novel Screening Kit for Colorectal Cancer Using the Immunochromatographic Fecal Tumor M2 Pyruvate Kinase Test.

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.

Elevated fecal M2-pyruvate kinase in children with cystic fibrosis: a clue to the increased risk of intestinal malignancy in adulthood?

BACKGROUND AND AIM: Adult patients with cystic fibrosis (CF) have an increased risk of gastrointestinal malignancies. We hypothesized that increased intestinal cell turnover beginning in childhood may explain the increased risk of malignancy in early adulthood. Therefore, we aimed to measure fecal M2-pyruvate kinase (M2-PK), a biomarker of intestinal cell turnover, in children with CF. To assess whether the increased cell turnover is secondary to intestinal inflammation, the secondary aims were to measure fecal calprotectin and evaluate its association with fecal M2-PK. METHODS: Fecal samples, for M2-PK and calprotectin measurements, were prospectively collected from children with CF and healthy controls (HC). RESULTS: Thirty-three children with CF (mean [standard deviation] 7.3 [3.8] years old; 29 pancreatic insufficient [PI]) were enrolled and compared with 33 age-matched HC. Fecal M2-PK in CF patients (median [interquartile range, IQR]: 4.7 [1.5-9.7]) was greater than HC (1.0 [1.0-1.0] U/mL; P < 0.0001), and higher in PI (median [IQR]: 5.1 [1.8-13.7]) than pancreatic sufficient patients (1.0 [1.0-1.0] U/mL; P = 0.002). Fecal calprotectin was significantly elevated in CF than HC (median [IQR] 61.3 [43.8-143.8] vs 19.5 [19.5-35.1] mg/kg; P < 0.0001). However, there was no correlation between fecal M2-PK and fecal calprotectin levels among subjects with CF (r = 0.29; P = 0.1). CONCLUSION: Increased intestinal cell turnover is present in children with PI CF. The lack of relationship between fecal M2-PK and calprotectin suggests that contributing factor(s) other than inflammation may be present.

[Indicators of inflammatory process in stool in diagnostics and monitoring of inflammatory bowel diseases]. / Wskazniki stanu zapalnego badane w stolcu w diagnostyce i monitorowaniu leczenia nieswoistych chorób zapalnych jelit.

In the recent decades the rapid development of the studies on new methods used in diagnosis, differential diagnosis, and monitoring the treatment of inflammatory bowel diseases has been observed. To the diagnostics of gastrointestinal disorders new methods such as endoscopic capsule and imaging methods including magnetic resonance have been introduced. Markers of inflammation detected in stool play significant role in the diagnostics. To the best known belong calprotectine and lactoferrin, which are produced by neutral granulocytes. In the present review we have presented the clinical usefulness of detection in the stool of calprotectin, lectoferrin, S100A12 protein and pyruvate kinase. Clinical usefulness of these markers were used in diagnosis, assessment of the treatment results, disease relapse and mucosal healing in inflammatory bowel disease. Determination of fecal calprotectin and lactoferrin in the process of mucosal healing in ulcerative colitis or Crohn's disease are of particular value. Confirmation of these results in multicenter prospective trials will enable in the future to reduce the number of control colonoscopies, which in children are performer under general anesthesia.