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Digestive system cancers are the most frequent cancers worldwide and often associated with poor prognosis because of their invasive and metastatic characteristics. Recent studies have found that the plasticity of cancer cells can impart cancer stem-like properties via the epithelial-mesenchymal transition (EMT). Cancer stem-like properties such as tumor initiation are integral to the formation of metastasis, which is the main cause of poor prognosis. Numerous markers of cancer stem cells (CSCs) have been identified in many types of cancer. Therefore, CSCs, via their stem cell-like functions, may play an important role in prognosis after surgery. While several reports have described prognostic analysis using CSC markers, few reviews have summarized CSCs and their association with prognosis. Herein, we review the prognostic potential of eight CSC markers, CD133, CD44, CD90, ALDH1A1, EPCAM, SOX2, SOX9, and LGR5, in digestive cancers including those of the pancreas, colon, liver, gastric, and esophagus.

Background: Colorectal cancer is the third most common cancer worldwide. If biomarkers can be identified in liquid biopsy, diagnosis and treatment can be optimized even when cancerous tissues are not available. The purpose of this study was to identify proteins from liquid biopsy that would be useful as markers of poor prognosis., Methods: First, we comprehensively analyzed serum proteins to identify potential biomarkers and focused on serum lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1). The relationship between LOX-1 and the prognosis of patients with colorectal cancer has not been reported. Next, we validated this marker using serum samples from 238 patients with colorectal cancer by ELISA and 100 tissue samples by immunohistochemical staining., Results: The optimal cut-off value of serum LOX-1 was 538.7 pg/mL according to time-dependent receiver operating characteristics curve analysis. The overall survival of patients with high levels of serum LOX-1 was significantly poorer than that of individuals with low levels of LOX-1 in the training and test datasets. In multivariate analysis for overall survival, serum LOX-1 was an independent prognostic factor identified in liquid biopsy (hazard ratio = 1.729, p = 0.027). The prognosis of patients with high LOX-1 expression in tumor tissues was significantly poorer than that of individuals with low expression (p =0.047 ). Additionally, inflammatory factors such as white blood cell count, C-reactive protein level, neutrophil/lymphocyte ratio, and monocyte/lymphocyte ratio were significantly higher in the group with high serum LOX-1 levels., Conclusions: Serum LOX-1 might be a useful biomarker of poor prognosis in colorectal cancer.

The cancer stroma is important in cancer development, however, whether the aberrant expression of microRNAs (miRNAs) in the cancer stroma is associated with cancer progression remains to be fully elucidated. The aim of the present study was to identify the miRNAs associated with liver metastasis in the cancer stroma of human colorectal cancer (CRC). Using laser capture microdissection, cancer stroma was obtained from the primary lesion of six patients with CRC with liver metastasis (CRCwLM) and six patients with CRC without liver metastasis (CRCwoLM), and miRNA microarray analysis was performed. Candidate miRNA expression status in the stroma was validated by reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) analysis in 40 CRC cases (wLM, n=20; woLM, n=20), and the association between miRNA expression and clinicopathological factors was assessed in 101 advanced CRC samples. The localization of candidate miRNAs in CRCs was analyzed using in situ hybridization analysis (ISH). The microarray analysis identified six miRNAs with expression differing between the CRCwLM and CRCwoLM cancer stroma. Validation using RT‑qPCR analysis of the stroma showed that the expression levels of miR‑221 and miR‑222 in the cancer stroma were significantly higher in CRCwLM than in CRCwoLM. The RT‑qPCR analysis of 101 CRC samples showed that a high expression level of miR‑221 or miR‑222 in the cancer stroma was associated with liver metastasis, distant metastasis, and shorter overall survival rate of patients with CRC (P<0.05). Increased levels of miR‑221 and miR‑222 were observed in cancer cells and in fibroblasts in the stromal tissue in the ISH analysis. The results suggested that the overexpression of miR‑221 and miR‑222 in the cancer stroma is associated with the metastatic activity and malignant potential in patients with CRC.

Various vaccine treatments against metastatic colorectal cancer have been developed and applied. However, to improve the efficacy of immunotherapy, biomarkers that can predict the effects are needed. It has been reported that various microRNAs (miRNAs) in peripheral blood may be useful as non-invasive biomarkers. In this study, miRNAs influencing the efficacy of vaccine treatment were screened for in a microarray analysis of 13 plasma samples that were obtained from patients prior to vaccine treatment. To validate the screening results, real-time RT-PCR was performed using 93 plasma samples obtained from patients prior to vaccine treatment. Four candidate miRNAs were selected according to the results of the comprehensive analysis of miRNA expression, which were ranked using the Fisher criterion and the absolute value of the log2 ratio in the screening analysis. The validation analysis showed that in the HLA-A*2402‑matched patient group (vaccine-treated group), patients with a high expression of plasma miR-6826 had a poorer prognosis than those with a low expression (P=0.048). In contrast, in the HLA-A*2402-unmatched patient group (control group), there was no difference between the patients with high or low plasma miR-6826 expression (P=0.168). Similar results were obtained in the analysis of miR-6875 (P=0.029 and P=0.754, respectively). Moreover, multivariate analysis of the Cox regression model indicated that the expression of miR-6826 was the most significant predictor for overall survival (P=0.003, hazard ratio, 3.670). In conclusion, plasma miR-6826 and miR-6875 may be predictive biomarkers for a poor response to vaccine treatment. Although further clarification is needed regarding the functions of miR-6826 and miR-6875 and their relationship to immune‑related molecules, plasma miR-6826 and miR-6875 may be useful negative biomarkers for predicting the efficacy of vaccine treatment.

We previously reported a phase II study of a cancer vaccine using five novel peptides recognized by HLA-A*2402-restricted CTL in combination with oxaliplatin-containing chemotherapy (FXV study) as first-line therapy for patients with metastatic colorectal cancer and demonstrated the safety and promising potential of our five-peptide cocktail. The objective of this analysis was to identify predictive biomarkers for identifying patients who are likely to receive a clinical benefit from immunochemotherapy. Circulating cell-free DNA (cfDNA) in plasma has been reported to be a candidate molecular biomarker for the efficacy of anticancer therapy. Unlike uniformly truncated small-sized DNA released from apoptotic normal cells, DNA released from necrotic cancer cells varies in size. The integrity of plasma cfDNA (i.e. the ratio of longer fragments [400 bp] to shorter fragments [100 bp] of cfDNA), may be clinically useful for detecting colorectal cancer progression. We assessed plasma samples collected from 93 patients prior to receiving immunochemotherapy. The cfDNA levels and integrity were analyzed by semi-quantitative real-time PCR. Progression-free survival was significantly better in patients with a low plasma cfDNA integrity value than in those with a high value (P = 0.0027). Surprisingly, in the HLA-A*2402-matched group, patients with a low plasma cfDNA integrity value had significantly better progression-free survival than those with a high value (P = 0.0015). This difference was not observed in the HLA-A*2402-unmatched group. In conclusion, the integrity of plasma cfDNA may provide important clinical information and may be a useful predictive biomarker of the outcome of immunotherapy in metastatic colorectal cancer., (© 2016 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

Background: There are few blood tests for an efficient detection of hepatocellular carcinoma (HCC) associated with hepatitis C virus (HCV) infection., Methods: The abilities of quantitative analyses of 7 genes hypermethylation in serum DNA, α-fetoprotein (AFP) and prothrombin-induced vitamin K absence II (PIVKA-II), and various combinations to detect HCC were evaluated in a training cohort of 164 HCV-infected patients (108 HCCs; 56 non-HCCs). An optimal hybrid detector, built using data for 2 methylated genes (SPINT2 and SRD5A2), AFP, and PIVKA-II, achieved the most satisfactory ability to detect HCC in the training cohort. We evaluated the ability of the optimal hybrid detector to detect HCC in an independent validation cohort of 258 consecutive HCV-infected patients (112 HCCs; 146 non-HCCs) who were newly enrolled in 4 distinct institutes., Results: In the validation cohort of 258 patients, accuracy, sensitivity, and specificity of the hybrid detector for detection of HCC were 81.4%, 73.2%, and 87.7%, respectively. Notably, even when detecting HCC ≤ 2 cm in diameter, the hybrid detector maintained markedly high abilities (84.6% accuracy, 72.2% sensitivity, 87.7% specificity). Youden's index (sensitivity+specificity - 1) for HCC ≤ 2cm was 0.60, vastly much superior to the 0.39 for AFP at a cut-off value of 20 ng/ml and the 0.28 for PIVKA-II at a cut-off value of 40 mAU/ml., Conclusions: These results show that the optimal hybrid blood detector can detect HCV-related HCC more accurately., (Copyright © 2010 Elsevier B.V. All rights reserved.)

An increased level of glycolysis, an intracellular hallmark of neoplasms, enables cancer cells to survive under various conditions. To elucidate the role of increased glycolysis in the progression of hepatocellular carcinoma (HCC), we investigated the associations between the expression patterns of 14 glycolysis-related genes and clinicopathologic factors in 60 HCCs by using pooled transcriptome data. We then evaluated the therapeutic efficacy of the knockdown of ENO1, which is encoded by a glycolysis-related gene, in HCC cells. Among the 14 genes, levels of 8 genes (GPI, ALDOA, TPI1, GAPD, PGK, PGAM, ENO1 and PKM), all of which can be transcriptionally activated by hypoxia-inducible factor 1alpha (HIF-1alpha), were significantly higher in HCC with venous invasion (VI) than in HCC without VI. Our cluster analysis showed that HCC patients with activation of the 8 HIF-1alpha-regulated genes had significantly shorter overall survival (P=0.023) than did HCC patients without increased expression levels of these genes. The association between the levels of ENO1 and VI was confirmed in an independent sample set of 49 HCCs by real-time reverse-transcription PCR. The knockdown of ENO1 by small-interfering RNA significantly inhibited the proliferation of an HCC cell line (HLE cells) in both the glucose-rich and glucose-free conditions, accompanied by a decreased S phase and increased G2/M phase of the cell cycle. Collectively, these data suggest that activation of an HIF-1alpha-regulated glycolysis module is closely related to the aggressive phenotype of HCC, and that ENO1, a glycolysis module gene, might serve as a new target to circumvent HCC metastasis.

We previously developed a DNA microarray-based system that out-performs traditionally used clinical parameters for prediction of early intrahepatic recurrence (IHR) of hepatocellular carcinoma (HCC). Because DNA microarray is too expensive for daily clinical use, we used a quantitative real-time reverse transcription-polymerase chain reaction (QRT-PCR) to develop a lower-cost predictor for early IHR. From the 12 early IHR-related genes integrated in the previous predictor, we selected 6 genes whose levels showed the strongest association between data from the 2 distinct DNA microarray platforms with the same sample set. Expression of these 6 genes relative to that of GAPDH was measured by QRT-PCR in 82 HCCs. Of the 82 HCCs, 39 and 43 were assigned to training and independent test sets, respectively. By searching all combinations (n=2-6) of the 6 genes, we found an optimal combination of 3 genes (HLADRA, DDX17 and LAPTM5) that minimized the leave-one-out error for prediction of early IHR in the training set. The 3-gene predictor constructed with the Fisher linear classifier correctly predicted early IHR or non-recurrence in 35 (81.4%) of 43 HCCs in the independent test set and had a high positive predictive value of 72.7% and a high negative predictive value of 84.4%. Multivariate analysis with the stepwise logistic regression showed that the 3-gene predictor [F(x)<0] was an independent risk factor for early IHR (risk ratio, 13.6; p=0.006), indicating its potential as an easy-to-use predictor for accurate prediction of early IHR of HCC.