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The purpose was to investigate whether the eosinophil biomarker EMR1, ectopically expressed in colon cancer tumor cells, could be used to identify patients at risk for relapse after curative surgery. EMR1 mRNA levels were determined in primary tumors (n = 66) and lymph nodes (LNs; n = 377) from 121 colon cancer patients. Controls were resection margins of colon cancer tumors and LNs from patients with inflammatory bowel disease. Primary read-out was recurrency evaluated as disease-free survival time in the Kaplan–Meier survival model and hazard ratio calculation by uni- and multivariate Cox regression. High EMR1 levels in the regional LNs were associated with poor prognosis [hazard ratio 3.1 (1.2–8.0) at 5-year follow-up, p = 0.02]. Patients with a very poor prognosis were identified by combining EMR1 with CXCL17 analysis of LNs [hazard ratio 4.6 (1.1–19.7), p = 0.04]. High EMR1 levels in the primary tumor were associated with a good prognosis [hazard ratio 0.1 (0.02–0.9), p = 0.04]. Multivariate analysis strengthened the result for LNs but weakened the result for the primary tumor. These contradictory prognostic results probably relate to the prominent eosinophilia in the primary tumor, essentially lacking in LNs, where ectopically expressed EMR1 in tumor cells dominates. Thus, EMR1 expressed in tumor cells probably promotes tumor growth.

Introduction: Proteases play an important role in tumor progression. The predictive efficacy of proteases PRSS3 and PRSS22 mRNA levels for predicting relapse in surgically treated colon cancer (CC) patients was assessed.

Methods: mRNA expression was quantified in 371 half lymph nodes (LNs) from 121 CC patients, 77 control LNs (13 patients), 66 primary colon tumors, and 30 normal colon tissues of these patients. Patients were also stratified according to their CEA mRNA level. The occurrence of relapse following curative surgery was evaluated using the Cox regression and Kaplan-Meier survival model analyses. Protein expression was examined through immunohistochemistry.

Results: PRSS22 was superior to PRSS3 in identifying patients at risk of recurrence. Thus, high PRSS22 levels in LNs identified 76.5% of those who recurred, while PRSS3 only identified 17.6% of these patients and these were in TNM stages III and IV. The Kaplan-Meier analysis indicated that CC patients exhibiting elevated PRSS22 levels in lymph nodes experienced a reduction in survival time, averaging 37 months over the follow-up period (p = 0.009) and a 3-fold increased hazard risk (1.3–6.0; p = 0.01). In the group with low PRSS22 levels, only one patient experienced relapse at the 12-year follow-up when CEA mRNA analysis was included. A fraction of CEA-positive tumor cells expressed PRSS22 protein.

Conclusion: The importance of the secreted serine protease, S1 family member PRSS22 in tumor progression is highlighted. It shows promise as a biomarker for CC prognosis and as a target to prevent tumor spread by inhibiting its enzymatic activity.

Introduction: The aim was to investigate whether the stem cell marker LGR6 has prognostic value in colon cancer, alone or in combination with the prognostic biomarkers CEA and CXCL16.

Methods: LGR6 mRNA levels were determined in 370 half lymph nodes of 121 colon cancer patients. Ability to predict relapse after curative surgery was estimated by Kaplan-Meier survival model and Cox regression analyses.

Results: Patients with high LGR6 levels [LGR6(+)] had a decreased mean survival time of 11 months at 5-year follow-up and 47 months at 12-year follow-up, respectively, with hazard ratios of 3.2 and 2.8. LGR6 mRNA analysis added prognostic value to CEA and CXCL16 mRNA analysis. In the poor prognosis groups CEA(+) and CXCL16(+), further division was achieved by LGR6 analysis. LGR6(+) patients had a very poor prognosis. LGR6 also identified a small number of CEA(-), TNM stage I patients who relapsed suggesting stem cell origin of these tumors. LGR6 and LGR5 levels correlated strongly in lymph nodes of stage I and IV patients but not in stage II patients, suggesting that these stem cell markers are differentially regulated.

Conclusion: This study highlights LGR6 as a useful prognostic biomarker independently and in combination with CEA, CXCL16 or LGR5 identifying different risk groups.

Introduction: Approximately 25% of colon cancer (CC) patients having curative surgery will relapse. Therefore, it is crucial to identify patients with increased recurrence risk to offer them adjuvant chemotherapy. Three markers with prominent expression in fibroblasts: forkhead box Q1 (FOXQ1), matrix metalloproteinase-11 (MMP11), and thrombospondin-2 (THBS2), and the fibroblast expressed chemokine CXCL12 were selected for studies because of the critical role of fibroblasts in the microenvironment of the tumor.

Methods: The expression levels of the biomarkers were assessed in primary CC tumors, lymph nodes of CC patients and controls, and CC cell lines at mRNA and protein levels by real-time qRT-PCR and immunohistochemistry, respectively.

Results: FOXQ1, MMP11, and THBS2 mRNAs were expressed at significantly higher levels in primary tumors compared to normal colon (P=0.002, P<0.0001, and P<0.0001, respectively). In contrast, CXCL12 mRNA levels were higher in normal colon tissue. FOXQ1, MMP11, and THBS2 levels were also expressed at significantly higher levels in metastasis-positive lymph nodes compared to both metastasis-negative- and control nodes (P<0.0001/P=0.002, P<0.0001/P<0.0001, and P<0.0001/P<0.0001, respectively). Immuno-morphometry revealed that 30–40% of the tumor cells expressed FOXQ1, MMP11, and THBS2. FOXQ1 and THBS2 were barely detected in normal colon epithelium (P<0.0001), while MMP11 was expressed in normal colon epithelium at high levels.

Discussion: We conclude that CC tumor cells show ectopic expression of FOXQ1 and THBS2 possibly making these tumor cells independent of fibroblast cell support. The high expression levels of these two biomarkers in metastatic lymph nodes suggest that they are potential indicators of patients at risk for recurrence.

The significance of cancer stem cells (CSCs) in initiation and progression of colon cancer (CC) has been established. In this study, we investigated the utility of measuring mRNA expression levels of CSC markers EpCAM, LGR5 and LGR4 for predicting survival outcome in surgically treated CC patients. Expression levels were determined in 5 CC cell lines, 66 primary CC tumors and 382 regional lymph nodes of 121 CC patients. Prognostic relevance was determined using Kaplan‐Meier survival and Cox regression analyses. CC patients with lymph nodes expressing high levels of EpCAM, LGR5 or LGR4 (higher than a clinical cutoff of 0.07, 0.06 and 2.558 mRNA cop-ies/18S rRNA unit, respectively) had a decreased mean survival time of 32 months for EpCAM and 42 months for both LGR5 and LGR4 at a 12‐year follow‐up (p = 0.022, p = 0.005 and p = 0.011, respec-tively). Additional patients at risk for recurrence were detected when LGR5 was combined with the biomarkers CXCL17 or CEA plus CXCL16. In conclusion, the study underscores LGR5 as a particularly useful prognostic biomarker and illustrates the strength of combining biomarkers detecting different subpopulations of cancer cells and/or cells in the tumor microenvironment for predicting recurrence.

BACKGROUND: Lymph node metastasis is the single most important prognostic risk factor for recurrence in patients with colon cancer who have undergone curative surgery. The routine method for detecting disseminated tumor cells in lymph nodes is microscopic examination of one or a few hematoxylin and eosin-stained tissue sections by a trained pathologist. This method, however, is insensitive mainly because less than 1% of the lymph node volume is examined, leading to misclassification.

OBJECTIVE: This study aimed to investigate whether analysis of a selected group of biomarker mRNAs improves detection and characterization of lymph node metastases/micrometastases compared with the routine method.

DESIGN: This study is a side-by-side comparison of biomarker mRNA analysis and histopathology of 185 lymph nodes from patients with colon cancer representing stages I to IV, and an investigation of the importance of lymph node tissue volume for tumor cell detection.

SETTINGS: This is a collaborative study between a high-volume central hospital and a preclinical university institution.

PATIENTS: Fifty-seven patients who had undergone tumor resection for colon cancer were included.

MAIN OUTCOME MEASURES: The primary outcomes measured were mRNA copies per 18S rRNA copy of CEACAM5, KLK6, SLC35D3, POSTN, and MUC2 by multiplex assay and metastases/micrometastases detected by histopathology.

RESULTS: The number of tumor cell-positive lymph nodes was 1.33-fold higher based on CEACAM5 mRNA levels compared with histopathological examination. Increasing the tissue volume analyzed for CEACAM5 levels from an 80-µm section to half a lymph node increased the number of positive nodes from 34 of 107 to 80 of 107 (p < 0.0001). Similarly, the number of positive nodes for the aggressiveness marker KLK6 increased from 9 of 107 to 24 of 107.

LIMITATIONS: Only a limited number of individual lymph nodes per patient was available for analysis.

CONCLUSIONS: mRNA analysis of CEACAM5, KLK6, and SLC35D3 improves the detection of tumor cells in lymph nodes from patients surgically treated for colon cancer, and, together with POSTN and MUC2, it further allows characterization of the tumor cells with respect to aggressiveness and the tumor cell environment. See Video Abstract at https://links.lww.com/DCR/B650.

OBJECTIVE: The microenvironment of colon cancer (CC) is heterogeneous including cells of myeloid lineage affecting tumor growth and metastasis. Two functional subtypes of myeloid cells have been identified; one (M1) is tumor-inhibitory and the other one (M2) is tumor-promoting. Whether the three myeloid markers EMR1, CD206 and CD86 are expressed only in the infiltrating myeloid cells or also in the tumor cells was investigated.

METHODS: Expression of the myeloid markers was investigated in CC at the mRNA and protein levels in primary tumors and lymph nodes. mRNA expression was also determined in 5 CC cell lines. Protein expression was investigated by two-color immunofluorescence and consecutive-sections-immune-staining combined with morphometry using specific antibodies for the myeloid cell markers and the epithelial cell markers CEACAM5 and EpCAM.

RESULTS: EMR1 and CD86, but not CD206, mRNA levels were significantly higher in CC primary tumors compared to apparently normal colon tissue (P <  0.0001). EMR1 mRNA levels were significantly higher in both hematoxylin-eosin positive (H&E(+)) and H&E(-) lymph nodes of CC patients compared to control nodes (P = 0.03 and P = 0.01, respectively). EMR1 and CD206 mRNAs were expressed in 4/5 and 5/5 CC cell lines, respectively, while CD86 mRNA was not expressed. Immuno-morphometry revealed that about 20% of the tumor cells expressed EMR1 and CD206. Positive cells were tumor cells as revealed by anti-CEACAM5 and anti-EpCAM staining. The number of EMR1, CD206 and CD86 positive cells were significantly increased in CC primary tumors compared to normal colon tissue (P <  0.0001). However, CD206 was also expressed in normal colonocytes. Only EMR1 showed significantly increased numbers of positive tumor cells in H&E(+) nodes compared to H&E(-) nodes (P = 0.001). EMR1 expression in CC tumor cells correlated with CXCL17 expressing tumor cells.

CONCLUSION: EMR1, like the chemokine CXCL17, is ectopically expressed in colon cancer possibly in the same cancer cells.

Background and aims: Curative surgery saves approximate to 50% of all patients with colorectal cancer (CRC) while remaining patients have synchronous or will develop metachronous metastases. Presently, the single most important prognostic factor is histopathological detection of disseminated tumor cells in regional lymph nodes. However, the routine method has several limitations. The aim was to identify biomarker mRNAs that could be combined in a formula that would allow better prediction of patients' survival after surgery.

Methods: Screening for biomarker mRNAs overexpressed in CRC was performed by genome-wide hybridization bead array, with verification by qRT-PCR. Specific qRT-PCR assays with copy standards were developed for 5 selected genes and mRNA expression levels determined in lymph nodes from 174 CRC patients (517 nodes) and 24 control patients (118 nodes). Prognostic value of biomarker mRNAs was estimated. A cut-off was set using univariate Cox regression analysis and used for calculation of differences between patient groups in disease-free survival 12 years after surgery (Kaplan-Meier survival model) and risk for recurrent disease (Cox's regression analysis). A formula was constructed for evaluation of the prognostic value of the biomarkers in combination.

Results: Two new biomarkers, SLC35D3 and POSTN with prognostic value were identified. SLC35D3 was expressed in the epithelium derived tumor cells and POSTN in fibroblasts. Combined with CEACAM5, KLK6 and MUC2 they could be used to identify risk groups. A formula was constructed using CEACAM5 as denominator for KLK6, SLC35D3 and MUC2 and 18S rRNA as denominator for POSTN. The formula yielded 5 categories (-1, 0, 1, 2, 3). Categories (-1 and 0) had good prognosis, categories (1 and 2) relatively poor prognosis and category (3) very poor prognosis.

Conclusion: Lymph node analysis using 5 selected biomarker mRNAs and 18S rRNA in combination allowed allocation of CRC patients to different risk categories with respect to recurrent disease.

OBJECTIVE: Several studies indicate that macrophage migration inhibitory factor 1 plays a role for tumor progression in colon cancer. We investigated whether determination of migration inhibitory factor 1 mRNA expression levels in lymph nodes of colon cancer patients could be used as a prognostic marker.

METHODS: Expression levels of migration inhibitory factor 1 and carcinoembryonic antigen mRNAs were assessed in primary tumors and regional lymph nodes of 123 colon cancer patients (stages I-IV), and in colon cancer- and immune cell lines using quantitative reverse transcriptase-polymerase chain reaction. Expression of migration inhibitory factor 1 protein was investigated by two-color immunohistochemistry and immunomorphometry.

RESULTS: Migration inhibitory factor 1 mRNA was expressed at 60 times higher levels in primary colon cancer tumors compared to normal colonic tissue (medians 8.2 and 0.2 mRNA copies/18S rRNA unit; p < .0001). A highly significant difference in mRNA expression levels was found between hematoxylin-eosin positive lymph nodes and hematoxylin-eosin negative lymph nodes (p < .0001). Migration inhibitory factor 1 and carcinoembryonic antigen proteins were simultaneously expressed in many colon cancer-tumor cells. Kaplan-Meier survival model and hazard ratio analysis, using a cutoff level at 2.19 mRNA copies/18S rRNA unit, revealed that patients with lymph nodes expressing high levels of migration inhibitory factor 1 mRNA had a 3.5-fold (p = .04) higher risk for recurrence, associated with a small, but significant, difference in mean survival time (7 months, p = .03) at 12 years of follow-up.

CONCLUSION: Although migration inhibitory factor 1 mRNA expression levels were related to severity of disease and lymph node analysis revealed that colon cancer patients with high levels had a shorter survival time after surgery than those with low levels, the difference was small and probably not useful in clinical practice.

hemokines are important in the development and progression of tumors. We investigated the expression of CXCL14 and CXCL16 in colon cancer. Expression of mRNA was assessed in primary tumors and lymph nodes and CXCL16 mRNA levels were correlated to patient’s survival. Protein expression was investigated by two-color immunofluorescence and immunomorphometry. CXCL14 and CXCL16 mRNA levels and protein expression were significantly higher in colon cancer primary tumors compared to apparently normal colon tissue. Positive cells were tumor cells, as revealed by anti-CEA and anti-EpCAM staining. CXCL16, but not CXCL14, mRNA levels were significantly higher in hematoxylin and eosin positive (H&E(+)) compared to H&E(−) colon cancer lymph nodes or control nodes (P < 0.0001). CXCL16 mRNA was expressed in 5/5 colon cancer cell lines while CXCL14 was expressed significantly in only one. Kaplan-Meier analysis revealed that colon cancer patients with lymph nodes expressing high or very high levels (7.2 and 11.4 copies/18S rRNA unit, respectively) of CXCL16 mRNA had a decreased mean survival time of 30 and 46 months at the 12-year follow-up (P = 0.04, P = 0.005, respectively). In conclusion, high expression of CXCL16 mRNA in regional lymph nodes of colon cancer patients is a sign of a poor prognosis.