Proton pump inhibitor use is associated with elevated faecal calprotectin levels. A cross-sectional study on subjects referred for colonoscopy.

OBJECTIVES: Faecal Calprotectin (FC) is a sensitive marker for gut inflammation. However, slightly elevated FC levels are also common in subjects without inflammation. We investigated the association between FC and clinical factors including concomitant use of medical therapy in patients with a normal colonoscopy. MATERIAL AND METHODS: Out-patients (n = 1263) referred for colonoscopy, performed FC test (CALPRO) the day before the start of bowel preparation. All subjects answered questionnaires that included questions on the present and past health history, concomitant medical treatment and gastrointestinal symptoms (GSRS). A medical record chart review was performed to check for concomitant disease, cause of referral and the result of the colonoscopy including biopsies. Inclusion criteria were a normal colonoscopy. Exclusion criteria were inflammatory bowel disease, colon cancer and high-grade dysplasia. RESULTS: Five hundred ninety subjects fulfilled the inclusion criteria and completed the study. Thirty-six per cent of the subjects had a FC >50 µg/g. In a logistic regression analysis, age (adjusted OR: 1.051; CI: 1.032-1.071), and the use of proton pump inhibitors (adjusted OR: 3.843; CI: 2.338-6.316), non-steroid anti-inflammatory drugs (adjusted OR: 2.411; CI: 1.162-5.002) and acetylsalicylic acid (adjusted OR: 2.934; CI: 1.085-3.448) were significantly associated with an elevated FC (>50 µg/g). CONCLUSIONS: More than one-third of the patients with a normal colonoscopy performed in clinical routine had a slightly elevated FC level. Our results emphasise the need for attention to age, the use of proton pump inhibitors, non-steroid anti-inflammatory drugs and acetylsalicylic acid in the interpretation of FC tests in clinical practice.

Improved monitoring of inflammatory activity in patients with ulcerative colitis by combination of faecal tests for haemoglobin and calprotectin.

Faecal calprotectin (FC) tests and faecal immunological tests (FIT) for haemoglobin have been used to monitor disease activity in patients with ulcerative colitis (UC) but used alone they have some limitation concerning the predictive ability. We aimed to test if an FC test used in combination with FIT could improve the predictive ability. Consecutive out-patients with UC (n = 93) who were admitted for colonoscopy completed a single faecal sample before the start of bowel preparation. A quantitative CALPRO® calprotectin ELISA test and a qualitative FIT (cut-off < 40 ng/mL) were analyzed. An estimated Mayo score and a score of histological inflammation was performed blinded to the result of the faecal tests. The sensitivity, specificity, negative predictive value and positive predictive value for endoscopic inflammation (Mayo score > 1) was for FIT 85%, 83%, 96%, 57% and for FC > 186 µg/g 73%, 87%, 87%, 54%. Corresponding results for FIT*FC > 186 µg/g (at least one test positive) were 92%, 69%, 97%, 43%. For detecting moderate/severe histological inflammation the results were for FIT 69%, 79%, 92%, 43%, for FC > 75 µg/g 95%, 62%, 98%, 41%, and for FIT*FC > 75 µg/g 100%, 60%, 100%, 36%. None of the markers alone or in combination were useful to predict deep remission (Mayo score = 0 and no histological inflammation). We conclude that using the combination of an FC test and FIT shows minor improvement in predictive ability for inflammatory activity and remission in patients with UC.

Cancer-associated fecal microbial markers in colorectal cancer detection.

Colorectal cancer (CRC) is the second most common cause of cancer death in the western world. An effective screening program leading to early detection of disease would severely reduce the mortality of CRC. Alterations in the gut microbiota have been linked to CRC, but the potential of microbial markers for use in CRC screening has been largely unstudied. We used a nested case-control study of 238 study subjects to explore the use of microbial markers for clbA+ bacteria harboring the pks pathogenicity island, afa-C+ diffusely adherent Escherichia coli harboring the afa-1 operon, and Fusobacterium nucleatum in stool as potential screening markers for CRC. We found that individual markers for clbA+ bacteria and F. nucleatum were more abundant in stool of patients with CRC, and could predict cancer with a relatively high specificity (81.5% and 76.9%, respectively) and with a sensitivity of 56.4% and 69.2%, respectively. In a combined test of clbA+ bacteria and F. nucleatum, CRC was detected with a specificity of 63.1% and a sensitivity of 84.6%. Our findings support a potential value of microbial factors in stool as putative noninvasive biomarkers for CRC detection. We propose that microbial markers may represent an important future screening strategy for CRC, selecting patients with a "high-risk" microbial pattern to other further diagnostic procedures such as colonoscopy.

SOX2 expression is associated with a cancer stem cell state and down-regulation of CDX2 in colorectal cancer.

BACKGROUND: To improve current treatment strategies for patients with aggressive colorectal cancer (CRC), the molecular understanding of subgroups of CRC with poor prognosis is of vast importance. SOX2 positive tumors have been associated with a poor patient outcome, but the functional role of SOX2 in CRC patient prognosis is still unclear. METHODS: An in vitro cell culture model expressing SOX2 was used to investigate the functional role of SOX2 in CRC. In vitro findings were verified using RNA from fresh frozen tumor tissue or immunohistochemistry on formalin fixed paraffin embedded (FFPE) tumor tissue from a cohort of 445 CRC patients. RESULTS: Using our in vitro model, we found that SOX2 expressing cells displayed several characteristics of cancer stem cells; such as a decreased proliferative rate, a spheroid growth pattern, and increased expression of stem cell markers CD24 and CD44. Cells expressing SOX2 also showed down-regulated expression of the intestinal epithelial marker CDX2. We next evaluated CDX2 expression in our patient cohort. CDX2 down-regulation was more often found in right sided tumors of high grade and high stage. Furthermore, a decreased expression of CDX2 was closely linked to MSI, CIMP-high as well as BRAF mutated tumors. A decreased expression of CDX2 was also, in a stepwise manner, strongly correlated to a poor patient prognosis. When looking at SOX2 expression in relation to CDX2, we found that SOX2 expressing tumors more often displayed a down-regulated expression of CDX2. In addition, SOX2 expressing tumors with a down-regulated CDX2 expression had a worse patient prognosis compared to those with retained CDX2 expression. CONCLUSIONS: Our results indicate that SOX2 expression induces a cellular stem cell state in human CRC with a decreased expression of CDX2. Furthermore, a down-regulated expression of CDX2 results in a poor patient prognosis in CRC and at least part of the prognostic importance of SOX2 is mediated through CDX2 down-regulation.

One-carbon metabolism and CpG island methylator phenotype status in incident colorectal cancer: a nested case-referent study.

OBJECTIVE: We related prediagnostic plasma folate, vitamin B12, and total homocysteine concentrations, and the MTHFR 677C>T and 1298A>C polymorphisms, to the risk of colorectal cancer with and without the CpG island methylator phenotype (CIMP). METHODS: This was a nested case-referent study of 190 cases and double, matched referents from the large, population-based Northern Sweden Health and Disease Study. Using archival tumor tissue, promoter methylation in an eight-gene panel was analyzed by MethyLight. RESULTS: A reduced risk of CIMP-low/CIMP-high CRC (> or =1 gene methylated) was observed in subjects with very low plasma folate concentrations [multivariate odds ratio 2.96 (95% CI 1.24-7.08) for quintiles two to five versus one (lowest)]. With the exception of a reduced risk in MTHFR 677 TT-homozygotes, none of the other one-carbon variables were associated with the risk of CIMP-low/CIMP-high CRC. For CIMP-negative CRC, only the MTHFR polymorphisms were statistically significantly related to risk, inversely for 677C>T and positively for 1298A>C, but a tendency toward a reduced risk was observed in subjects with an adequate methyl availability, combining the plasma variables [multivariate odds ratio 0.61 (95% CI 0.32-1.15)]. CONCLUSION: Though limited by low power, these findings suggest the possibility of different roles for one-carbon metabolism in different pathways of colorectal tumorigenesis.

Parvimonas micra as a putative non-invasive faecal biomarker for colorectal cancer.

The use of faecal microbial markers as non-invasive biomarkers for colorectal cancer (CRC) has been suggested, but not fully elucidated. Here, we have evaluated the importance of Parvimonas micra as a potential non-invasive faecal biomarker in CRC and its relation to other microbial biomarkers. The levels of P. micra, F. nucleatum and clbA + bacteria were quantified using qPCR in faecal samples from a population-based cohort of patients undergoing colonoscopy due to symptoms from the large bowel. The study included 38 CRC patients, 128 patients with dysplasia and 63 controls. The results were validated in a second consecutive CRC cohort including faecal samples from 238 CRC patients and 94 controls. We found significantly higher levels of P. micra in faecal samples from CRC patients compared to controls. A test for P. micra could detect CRC with a specificity of 87.3% and a sensitivity of 60.5%. In addition, we found that combining P. micra with other microbial markers, could further enhance test sensitivity. Our findings support the potential use of P. micra as a non-invasive biomarker for CRC. Together with other microbial faecal markers, P. micra may identify patients with "high risk" microbial patterns, indicating increased risk and incidence of cancer.

The infiltration, and prognostic importance, of Th1 lymphocytes vary in molecular subgroups of colorectal cancer.

Giving strong prognostic information, T-cell infiltration is on the verge of becoming an additional component in the routine clinical setting for classification of colorectal cancer (CRC). With a view to further improving the tools for prognostic evaluation, we have studied how Th1 lymphocyte infiltration correlates with prognosis not only by quantity, but also by subsite, within CRCs with different molecular characteristics (microsatellite instability, CpG island methylator phenotype status, and BRAF and KRAS mutational status). We evaluated the Th1 marker T-bet by immunohistochemistry in 418 archival tumour tissue samples from patients who underwent surgical resection for CRC. We found that a high number of infiltrating Th1 lymphocytes is strongly associated with an improved prognosis in patients with CRC, irrespective of intratumoural subsite, and that both extent of infiltration and patient outcome differ according to molecular subgroup. In brief, microsatellite instability, CpG island methylator phenotype-high and BRAF mutated tumours showed increased infiltration of Th1 lymphocytes, and the most pronounced prognostic effect of Th1 infiltration was found in these tumours. Interestingly, BRAF mutated tumours were found to be more highly infiltrated by Th1 lymphocytes than BRAF wild-type tumours whereas the opposite was seen for KRAS mutated tumours. These differences could be explained at least partly by our finding that BRAF mutated, in contrast to KRAS mutated, CRC cell lines and tumour specimens expressed higher levels of the Th1-attracting chemokine CXCL10, and reduced levels of CCL22 and TGFB1, stimulating Th2/Treg recruitment and polarisation. In conclusion, the strong prognostic importance of Th1 lymphocyte infiltration in CRC was found at all subsites evaluated, and it remained significant in multivariable analyses, indicating that T-bet may be a valuable marker in the clinical setting. Our results also indicate that T-bet is of value when analysed in molecular subgroups of CRC, allowing identification of patients with especially poor prognosis who are in need of extended treatment.

SOX2 expression is regulated by BRAF and contributes to poor patient prognosis in colorectal cancer.

Sporadic colorectal cancer (CRC) is a common malignancy and also one of the main causes of cancer deaths worldwide. Aberrant expression of the transcription factor SOX2 has recently been observed in several cancer types, but its role in CRC has not been fully elucidated. Here we studied the expression of SOX2 in 441 CRC patients by immunohistochemistry and related the expression to clinicopathological and molecular variables and patient prognosis. SOX2 was expressed in 11% of the tumors and was significantly associated to BRAFV600E mutation, but not to KRAS mutations (codon 12 and 13). SOX2 positivity was correlated to poor patient survival, especially in BRAFV600E mutated cases. In vitro studies showed that cells expressing the constitutively active BRAFV600E had increased SOX2 expression, a finding not found in cells expressing KRASG12V. Furthermore, blocking downstream BRAF signalling using a MEK-inhibitor resulted in a decreased expression of SOX2. Since SOX2 overexpression has been correlated to increased migration and invasion, we investigated the SOX2 expression in human CRC liver metastasis and found that a SOX2 positive primary CRC also had SOX2 expression in corresponding liver metastases. Finally we found that cells overexpressing SOX2 in vitro showed enhanced expression of FGFR1, which has been reported to correlate with liver metastasis in CRC. Our novel findings suggest that SOX2 expression is partly regulated by BRAF signalling, and an increased SOX2 expression may promote CRC metastasis and mediate a poor patient prognosis.

The role of the CpG island methylator phenotype in colorectal cancer prognosis depends on microsatellite instability screening status.

PURPOSE: The aim of this study was to relate the CpG island methylator phenotype (CIMP; characterized by extensive promoter hypermethylation) to cancer-specific survival in colorectal cancer, taking into consideration relevant clinicopathologic factors, such as microsatellite instability (MSI) screening status and the BRAF V600E mutation. EXPERIMENTAL DESIGN: Archival tumor samples from 190 patients from the Northern Sweden Health and Disease Study (NSHDS) and 414 patients from the Colorectal Cancer in Umeå Study (CRUMS), including 574 with cancer-specific survival data, were analyzed for an eight-gene CIMP panel using quantitative real-time PCR (MethyLight). MSI screening status was assessed by immunohistochemistry. RESULTS: CIMP-low patients had a shorter cancer-specific survival compared with CIMP-negative patients (multivariate hazard ratio in NSHDS, 2.01; 95% confidence interval, 1.20-3.37; multivariate hazard ratio in CRUMS, 1.48; 95% confidence interval, 1.00-2.22). This result was similar in subgroups based on MSI screening status and was statistically significant in microsatellite stable (MSS) tumors in NSHDS. For CIMP-high patients, a shorter cancer-specific survival compared with CIMP-negative patients was observed in the MSS subgroup. Statistical significance was lost after adjusting for the BRAF mutation, but the main findings were generally unaffected. CONCLUSIONS: In this study, we found a poor prognosis in CIMP-low patients regardless of MSI screening status, and in CIMP-high patients with MSS. Although not consistently statistically significant, these results were consistent in two separate patient groups and emphasize the potential importance of CIMP and MSI status in colorectal cancer research.