Gene expression profiles of epidermal growth factor receptor, vascular endothelial growth factor and hypoxia-inducible factor-1 with special reference to local responsiveness to neoadjuvant chemoradiotherapy and disease recurrence after rectal cancer surgery

HIF-1α Mediates Immunosuppression and Chemoresistance in Colorectal Cancer by Inhibiting CXCL9, -10 and -11

Uncertainty exists regarding the mechanisms by which hypoxia-inducible factors (HIFs) control CD8+T-cell migration into tumor microenvironments. Here, we found that HIF-1α knockdown or overexpression resulted in increased or decreased CXCL9, -10, and -11 expression in vitro, respectively. Gene Set Variation Analysis revealed that elevated HIF-1α levels correlated with a poor prognosis, severe pathological stage, and an absence of CD8+ T cells in the tumor microenvironment in colorectal cancer (CRC) patients. HIF-1α was inversely associated with pathways beneficial to anti-tumor immunotherapy and cytokine/chemokine function. In vivo, inhibiting HIF-1α or its upstream regulator BIRC2 significantly suppressed tumor growth and promoted CD8+ T-cell infiltration. CXCR3 neutralizing antibodies reversed these effects, implicating the involvement of CXCL9, -10, and -11/CXCR3 axis. The presence of HIF-1α weakened the upregulation of CXCL9, -10, and -11 by bleomycin and doxorubicin. Combining HIF-1α inhibition with bleomycin promoted CD8+ T-cell infiltration and tumor suppression in vivo. Moreover, doxorubicin could upregulate CXCL9, -10 and -11 by suppressing HIF-1α. Our findings highlight the potential of HIF-1α inhibition to improve CRC microenvironments and increase chemotherapy sensitivity.

The measurement and modification of hypoxia in colorectal cancer: overlooked but not forgotten

Tumour hypoxia is the inevitable consequence of a tumour's rapid growth and disorganized, inefficient vasculature. The compensatory mechanisms employed by tumours, and indeed the absence of oxygen itself, hinder the ability of all treatment modalities. The clinical consequence is poorer overall survival, disease-free survival, and locoregional control. Recognizing this, clinicians have been attenuating the effect of hypoxia, primarily with hypoxic modification or with hypoxia-activated pro-drugs, and notable success has been demonstrated. However, in the case of colorectal cancer (CRC), there is a general paucity of knowledge and evidence surrounding the measurement and modification of hypoxia, and this is possibly due to the comparative inaccessibility of such tumours. We specifically review the role of hypoxia in CRC and focus on the current evidence for the existence of hypoxia in CRC, the majority of which originates from indirect positron emission topography imaging with hypoxia selective radiotracers; the evidence correlating CRC hypoxia with poorer oncological outcome, which is largely based on the measurement of hypoxia inducible factor in correlation with clinical outcome; the evidence of hypoxic modification in CRC, of which no direct evidence exists, but is reflected in a number of indirect markers; the prognostic and monitoring implications of accurate CRC hypoxia quantification and its potential in the field of precision oncology; and the present and future imaging tools and technologies being developed for the measurement of CRC hypoxia, including the use of blood-oxygen-level-dependent magnetic resonance imaging and diffuse reflectance spectroscopy.

Evaluation of potential tumor markers that may predict neoadjuvant treatment efficiency in rectal cancer

Objectives

The recurrence of rectal cancer or its resistance to neoadjuvant treatment develops due to the adaptation to hypoxia, apoptosis or autophagy. Survivin, one of the inhibitors of apoptosis; Beclin 1, which is a positive regulator in the autophagy pathway; and hypoxia-inducible factor-1α (HIF-1α) and carbonic anhydrase-9 (CA9), which are associated with tumor tissue hypoxia, may be related to resistance to treatment. Our aim was to evaluate the potential tumor markers that may help to monitor the response to neoadjuvant treatment in locally advanced rectal cancer (RC).

Methods

Twenty-five patients with locally advanced RC were included in the study. Gene expression and protein levels of Beclin 1, Survivin, HIF-1α, and CA9 were analyzed in fresh tissue specimens and blood samples. The relationships of these markers to tumor staging and regression grade were evaluated.

Results

Higher blood CA9 gene expression levels and lower blood HIF-1α protein levels were found in the response group according to tumor regression grade. After neoadjuvant treatment, tissue Beclin 1 and blood Survivin gene expressions and tissue CA9, blood Beclin 1 and blood HIF-1α protein levels decreased significantly.

Conclusion

Beclin 1, Survivin, HIF-1α ve CA9 may help to predict the effects of the applied treatment approach.

Biomarkers and cell-based models to predict the outcome of neoadjuvant therapy for rectal cancer patients

Rectal cancer constitutes approximately one-third of all colorectal cancers and contributes to considerable mortality globally. In contrast to colon cancer, the standard treatment for localized rectal cancer often involves neoadjuvant chemoradiotherapy. Tumour response rates to treatment show substantial inter-patient heterogeneity, indicating a need for treatment stratification. Consequently researchers have attempted to establish new means for predicting tumour response in order to assist in treatment decisions. In this review we have summarized published findings regarding potential biomarkers to predict neoadjuvant treatment response for rectal cancer tumours. In addition, we describe cell-based models that can be utilized both for treatment prediction and for studying the complex mechanisms involved.

Predicting pathological response to chemoradiotherapy for rectal cancer: a systematic review

Introduction: Pathological complete response (pCR) rates of approximately 20% following neoadjuvant long-course chemoradiotherapy for rectal cancer have given rise to non-operative or watch-and-wait (W&W) management. To improve outcomes there has been significant research into predictors of response. The goal is to optimize selection for W&W, avoid chemoradiotherapy in those who won't benefit and improve treatment to maximize the clinical complete response (cCR) rate and the number of patients who can be considered for W&W.Areas covered: A systematic review of articles published 2008-2018 and indexed in PubMed, Embase or Medline was performed to identify predictors of pathological response (including pCR and recognized tumor regression grades) to fluoropyrimidine-based chemoradiotherapy in patients who underwent total mesorectal excision for rectal cancer. Evidence for clinical, biomarker and radiological predictors is discussed as well as potential future directions.Expert opinion: Our current ability to predict the response to chemoradiotherapy for rectal cancer is very limited. cCR of 40% has been achieved with total neoadjuvant therapy. If neoadjuvant treatment for rectal cancer continues to improve it is possible that the treatment for rectal cancer may eventually parallel that of anal squamous cell carcinoma, with surgery reserved for the minority of patients who don't respond to chemoradiotherapy.

Predicting Response to Neoadjuvant Therapy in Colorectal Cancer Patients the Role of Messenger-and Micro-RNA Profiling

Colorectal cancer patients' responses to neoadjuvant therapy undergo broad inter-individual variations. The aim of this systematic review is to identify a molecular signature that is predictive of colon cancer downstaging and/or downgrading after neoadjuvant therapy. Among the hundreds analysed in the available studies, only 19 messenger-RNAs (mRNAs) and six micro-RNAs (miRNAs) were differentially expressed in responders versus non-responders in two or more independent studies. Therefore, a mRNA/miRNA signature can be designed accordingly, with limitations caused by the retrospective nature of these studies, the heterogeneity in study designs and the downgrading/downstaging assessment criteria. This signature can be proposed to tailor neoadjuvant therapy regimens on an individual basis.

Network Mapping of Molecular Biomarkers Influencing Radiation Response in Rectal Cancer

Preoperative radiotherapy (RT) plays an important role in the management of locally advanced rectal cancer (RC). Tumor regression after RT shows marked variability, and robust molecular methods are needed to help predict likely response. The aim of this study was to review the current published literature and use Gene Ontology (GO) analysis to define key molecular biomarkers governing radiation response in RC. A systematic review of electronic bibliographic databases (Medline, Embase) was performed for original articles published between 2000 and 2015. Biomarkers were then classified according to biological function and incorporated into a hierarchical GO tree. Both significant and nonsignificant results were included in the analysis. Significance was binarized on the basis of univariate and multivariate statistics. Significance scores were calculated for each biological domain (or node), and a direct acyclic graph was generated for intuitive mapping of biological pathways and markers involved in RC radiation response. Seventy-two individual biomarkers across 74 studies were identified. On highest-order classification, molecular biomarkers falling within the domains of response to stress, cellular metabolism, and pathways inhibiting apoptosis were found to be the most influential in predicting radiosensitivity. Homogenizing biomarker data from original articles using controlled GO terminology demonstrated that cellular mechanisms of response to RT in RC-in particular the metabolic response to RT-may hold promise in developing radiotherapeutic biomarkers to help predict, and in the future modulate, radiation response.

Translating IDEA to Practice and Beyond: Managing Stage II and III Colon Cancer

Adjuvant fluoropyrimidine-based chemotherapy has been the standard of care for resected stage III colon cancer since the 1990s; the evolution from 12 to 6 months of fluoropyrimidine therapy and the addition of oxaliplatin to fluoropyrimidine therapy have led to the current accepted standard. However, controversies remain. What is the benefit of adjuvant chemotherapy in stage II disease, and in whom? What is the optimal duration of adjuvant chemotherapy? How should patients with early-stage colon cancer be followed after surgery and adjuvant treatment? Recent evidence has emerged to help inform these important questions, including the International Duration Evaluation of Adjuvant therapy (IDEA) collaboration, which is the largest, prospective study in colon cancer with 12,834 patients. This review discusses current and future risk stratification strategies in stage II disease: the optimal duration of adjuvant oxaliplatin-containing chemotherapy in stage II and III disease according to the IDEA study, and the recent evidence and updated recommendations for surveillance of early-stage colon cancer after resection.

Warburg effect, lactate dehydrogenase, and radio/chemo-therapy efficacy

The anaerobic metabolism of glucose by cancer cells, even under well-oxygenated conditions, has been documented by Otto Warburg as early as 1927. Micro-environmental hypoxia and intracellular pathways activating the hypoxia-related gene response, shift cancer cell metabolism to anaerobic pathways. In the current review, we focus on a major enzyme involved in anaerobic transformation of pyruvate to lactate, namely lactate dehydrogenase 5 (LDH5). The value of LDH5 as a marker of prognosis of cancer patients, as a predictor of response to radiotherapy (RT) and chemotherapy and, finally, as a major target for cancer treatment and radio-sensitization is reported and discussed. Clinical, translational and experimental data supporting the uniqueness of the LDHA gene and its product LDH5 isoenzyme are summarized and future directions for a metabolic treatment of cancer are highlighted.

Emergency resection surgery for colorectal cancer: Patterns of recurrent disease and survival

AIM

To evaluate prognostic pathological factors associated with early metachronous disease and adverse long-term survival in these patients.

METHODS

Clinical and histological features were analysed retrospectively over an eight-year period for prognostic impact on recurrent disease and overall survival in patients undergoing curative resection of a primary colorectal cancer.

RESULTS

A total of 266 patients underwent curative surgery during the study period. The median age of the study cohort was 68 year (range 26 to 91) with a follow-up of 7.9 years (range 4.6 to 12.6). Resection was undertaken electively in 225 (84.6%) patients and emergency resection in 35 (13.2%). Data on timing of surgery was missing in 6 patients. Recurrence was noted in 67 (25.2%) during the study period and was predominantly early within 3 years (82.1%) and involved hepatic metastasis in 73.1%. Emergency resection (OR = 3.60, P = 0.001), T4 stage (OR = 4.33, P < 0.001) and lymphovascular invasion (LVI) (OR = 2.37, P = 0.032) were associated with higher risk of recurrent disease. Emergency resection, T4 disease and a high lymph node ratio (LNR) were strong independent predictors of adverse long-term survival.

CONCLUSION

Emergency surgery is associated with adverse disease free and long-term survival. T4 disease, LVI and LNR provide strong independent predictive value of long-term outcome and can inform surveillance strategies to improve outcomes.

Gene expression levels of gamma-glutamyl hydrolase in tumor tissues may be a useful biomarker for the proper use of S-1 and tegafur-uracil/leucovorin in preoperative chemoradiotherapy for patients with rectal cancer

Purpose

Preoperative chemoradiotherapy (CRT) using 5-fluorouracil (5-FU)-based chemotherapy is the standard of care for rectal cancer. The effect of additional chemotherapy during the period between the completion of radiotherapy and surgery remains unclear. Predictive factors for CRT may differ between combination chemotherapy with S-1 and with tegafur-uracil/leucovorin (UFT/LV).

Methods

The subjects were 54 patients with locally advanced rectal cancer who received preoperative CRT with S-1 or UFT/LV. The pathological tumor response was assessed according to the tumor regression grade (TRG). The expression levels of 18 CRT-related genes were determined using RT-PCR assay.

Results

A pathological response (TRG 1-2) was observed in 23 patients (42.6%). In a multivariate logistic regression analysis for pathological response, the overall expression levels of four genes, HIF1A, MTHFD1, GGH and TYMS, were significant, and the accuracy rate of the predictive model was 83.3%. The effects of the gene expression levels of GGH on the response differed significantly according to the treatment regimen. The total pathological response rate of both high-GGH patients in the S-1 group and low-GGH patients in the UFT/LV group was 58.3%.

Conclusion

Additional treatment with 5-FU-based chemotherapy during the interval between radiotherapy and surgery is not beneficial in patients who have received 5-FU-based CRT. The expression levels of four genes, HIF1A, MTHFD1, GGH and TYMS, in tumor tissues can predict the response to preoperative CRT including either S-1 or UFT/LV. In particular, the gene expression level of GGH in tumor tissues may be a useful biomarker for the appropriate use of S-1 and UFT/LV in CRT.

Prognostic Impact of mRNA Expression Levels of HER1-4 (ERBB1-4) in Patients with Locally Advanced Rectal Cancer

Background. No predictive or prognostic biomarker is available for patients with locally advanced rectal cancer (LARC) undergoing perioperative chemoradiotherapy (CRT). Members of the human epidermal growth factor receptor (HER) family of receptor tyrosine kinases EGFR (HER1, ERBB1), HER2 (ERBB2), HER3 (ERBB3), and HER4 (ERBB4) are therapeutic targets in several cancers. The analysis was performed to assess expression levels and study the potential prognostic impact for disease-free and overall survival in patients with LARC. Patients and Methods. ERBB1–4 mRNA expression and tumor proliferation using Ki-67 (MKI67) mRNA were evaluated using RT-quantitative PCR in paraffin-embedded tumor samples from 86 patients (median age: 63) treated with capecitabine or 5-fluorouracil-based CRT within a phase 3 clinical trial. Results. A positive correlation of HER4 and HER2, HER3 and HER2, and HER4 and HER3 with each other was observed. Patients with high mRNA expression of ERBB1 (EGFR, HER1) had significantly increased risk for recurrence and death. Patients with high mRNA expression of MKI67 had reduced risk for relapse. Conclusion. This analysis suggests a prognostic impact of both ERBB1 and MKi67 mRNA expression in LARC patients treated with capecitabine or fluorouracil-based chemoradiotherapy.

Frequency of mitogen-activated protein kinase and phosphoinositide 3-kinase signaling pathway pathogenic alterations in EUS-FNA sampled malignant lymph nodes in rectal cancer with theranostic potential

BACKGROUND

Targeted next-generation sequencing has the potential to stratify a tumor by molecular subtype and aid the development of a biomarker profile for prognostic risk stratification and theranostic potential.

OBJECTIVE

To assess the frequency and distribution of pathogenic alterations in malignant lymph node cytology specimens.

DESIGN

Multigene molecular profiling of archived malignant EUS-FNA lymph node cytology specimens using the Ion Ampliseq Cancer Hotspot Panel v2, which targets at least 2855 possible mutations within 50 cancer-associated genes.

SETTING

Single tertiary referral center.

PATIENTS

Sporadic, treatment naive, locally advanced primary rectal cancer by EUS-FNA (n = 76) who subsequently completed neoadjuvant therapy with on-site oncologic surgery.

MAIN OUTCOME MEASUREMENTS

The frequency and distribution of pathogenic alterations in malignant lymph node cytology specimens by the mitogen-activated protein kinase (MAPK) or phosphoinositide 3-kinase (PI3K) signaling pathways, by KRAS or NRAS wild-type lymph node status, by extramesenteric lymph node status, and by a complete pathologic response status.

RESULTS

Eleven patients (14.5%) were 50-gene panel wild-type. Sixty-five patients had 139 pathogenic alterations (2 [1-3] per patient) in 13 of 50 evaluated genes. The following represent a spectrum of identified alterations: TP53 (n = 52; 68.4%), APC (n = 36; 47.4%), KRAS (n = 22; 28.9%), FBXW7 (n = 8; 10.5%), NRAS (n = 6; 7.9%), PIK3CA (n = 4; 5.3%), SMAD4 (n = 3; 3.9%), and BRAF (n = 3; 3.9%). Pathogenic alterations were identified in the MAPK and PI3K signaling pathways in 41% and 5% of patients, respectively.

LIMITATIONS

Findings were limited to a 50 cancer-associated gene analysis.

CONCLUSIONS

Molecular EUS lymph node assessments using cancer "hotspot" panels can identify pathogenic alteration frequency and distribution and have theranostic potential for individualized patient care.

Predictive and prognostic biomarkers for neoadjuvant chemoradiotherapy in locally advanced rectal cancer

Locally advanced rectal cancer is regularly treated with trimodality therapy consisting of neoadjuvant chemoradiation, surgery and adjuvant chemotherapy. There is a need for biomarkers to assess treatment response, and aid in stratification of patient risk to adapt and personalise components of the therapy. Currently, pathological stage and tumour regression grade are used to assess response. Experimental markers include proteins involved in cell proliferation, apoptosis, angiogenesis, the epithelial to mesenchymal transition and microsatellite instability. As yet, no single marker is sufficiently robust to have clinical utility. Microarrays that screen a tumour for multiple promising candidate markers, gene expression and microRNA profiling will likely have higher yield and it is expected that a combination or panel of markers would prove most useful. Moving forward, utilising serial samples of circulating tumour cells or circulating nucleic acids can potentially allow us to demonstrate tumour heterogeneity, document mutational changes and subsequently measure treatment response.

Genotypic characteristics of resistant tumors to pre-operative ionizing radiation in rectal cancer

Due to a wide range of clinical response in patients undergoing neo-adjuvant chemoradiation for rectal cancer it is essential to understand molecular factors that lead to the broad response observed in patients receiving the same form of treatment. Despite extensive research in this field, the exact mechanisms still remain elusive. Data raging from DNA-repair to specific molecules leading to cell survival as well as resistance to apoptosis have been investigated. Individually, or in combination, there is no single pathway that has become clinically applicable to date. In the following review, we describe the current status of various pathways that might lead to resistance to the therapeutic applications of ionizing radiation in rectal cancer.

The role of epithelial mesenchymal transition and resistance to neoadjuvant therapy in locally advanced rectal cancer

AIM

Nonresponse to neoadjuvant therapy is a significant challenge for clinicians managing solid cancers. This study aimed to determine whether epithelial mesenchymal transition (EMT) was associated with nonresponse to neoadjuvant therapy in patients with locally advanced rectal cancer.

METHOD

Representative tissue specimens from the tumour-invasive front of consecutive patients undergoing resection of rectal cancer from 2009 to 2011 were used. Patients with marked regression to neoadjuvant therapy were classified as responders and the remainder were classified as nonresponders. Markers of EMT included reduced immunohistochemical expression of membranous E-cadherin, increased nuclear beta-catenin expression and tumour budding. In-situ hybridization was used to assess the expression of microRNA-200c (mir200c), an upstream master-regulator of EMT.

RESULTS

Of 103 patients undergoing resection of rectal cancer, 69 received neoadjuvant chemoradiotherapy; 65% of these were nonresponders. Reduced expression of mir200c was significantly associated with a higher T grade. Reduced membranous E-cadherin, increased nuclear beta-catenin and tumour budding individually predicted the presence of extramural vascular invasion. Reduced E-cadherin, nucleic beta-catenin, reduced expression of mir200c and tumour budding were all significantly associated with nonresponse to neoadjuvant therapy (all P < 0.001). Reduced E-cadherin and expression of mir200c were both associated with reduced cancer-specific survival (log-rank P-values 0.036 and 0.009, respectively).

CONCLUSION

Targeted biomarkers of EMT were associated with nonresponse to neoadjuvant therapy and reduced survival in advanced rectal cancer. EMT may provide a practical clinical biomarker and a novel therapeutic target to improve the proportion of patients who respond to neoadjuvant therapy.

Can vascular endothelial growth factor and microvessel density be used as prognostic biomarkers for colorectal cancer? A systematic review and meta-analysis

Background. Vascular endothelial growth factor (VEGF) and microvessel density (MVD) are associated with greater incidence of metastases and decreased survival. Whether they can be used as prognostic indicators of colorectal cancer (CRC) is still controversial. Methods. The authors performed a meta-analysis using the results of a literature search of databases of PubMed and EMBASE, and the references of articles included in the analysis. Meta-analysis was performed using random effects model and hazard ratios (HRs) and 95% confidence intervals (CIs) as effect measures. Results. Twenty studies contributed to the analysis of VEGF, of which 16 were used for overall survival (OS) and 9 for disease-free survival (DFS). High VEGF levels has a relationship with unfavorable survival (OS: HR = 1.98, 95% CI: 1.30–3.02; DFS: HR = 2.10, 95% CI: 1.26–3.49) and a 4.22-fold increase in the rate of distant metastases. Analysis was performed on 18 studies for MVD; the results showed that patients with high MVD expression in tumors appeared to have poorer overall survival (HR = 1.39, 95% CI: 1.22–1.58) and were at a greater risk of having unfavorable clinical characteristics related to prognosis. Corresponding results were obtained from quantitative and/or qualitative analysis of clinicopathological. Conclusions. The meta-analysis demonstrates that VEGF and MVD can be used as prognostic biomarkers for CRC patients.

Colorectal cancer surveillance: what's new and what's next

The accumulated evidence from two decades of randomized controlled trials has not yet resolved the question of how best to monitor colorectal cancer (CRC) survivors for early detection of recurrent and metachronous disease or even whether doing so has its intended effect. A new wave of trial data in the coming years and an evolving knowledge of relevant biomarkers may bring us closer to understanding what surveillance strategies are most effective for a given subset of patients. To best apply these insights, a number of important research questions need to be addressed, and new decision making tools must be developed. In this review, we summarize available randomized controlled trial evidence comparing alternative surveillance testing strategies, describe ongoing trials in the area, and compare professional society recommendations for surveillance. In addition, we discuss innovations relevant to CRC surveillance and outline a research agenda which will inform a more risk-stratified and personalized approach to follow-up.

GDNF increases cell motility in human colon cancer through VEGF-VEGFR1 interaction

Glial cell line-derived neurotrophic factor (GDNF), a potent neurotrophic factor, has been shown to affect cancer cell metastasis and invasion. However, the molecular mechanisms underlying GDNF-induced colon cancer cell migration remain unclear. GDNF is found to be positively correlated with malignancy in human colon cancer patients. The migratory activities of two human colon cancer cell lines, HCT116 and SW480, were found to be enhanced in the presence of human GDNF. The expression of vascular endothelial growth factor (VEGF) was also increased in response to GDNF stimulation, along with VEGF mRNA expression and transcriptional activity. The enhancement of GDNF-induced cancer cell migration was antagonized by a VEGF-neutralizing antibody. Our results also showed that the expression of VEGF receptor 1 (VEGFR1) was increased in response to GDNF stimulation, whereas GDNF-induced cancer cell migration was reduced by a VEGFR inhibitor. The GDNF-induced VEGF expression was regulated by the p38 and PI3K/Akt signaling pathways. Treatment with GDNF increased nuclear hypoxia-inducible factor 1 α (HIF1α) accumulation and its transcriptional activity in a time-dependent manner. Moreover, GDNF increased hypoxia responsive element (HRE)-containing VEGF promoter transcriptional activity but not that of the HRE-deletion VEGF promoter construct. Inhibition of HIF1α by a pharmacological inhibitor or dominant-negative mutant reduced the GDNF-induced migratory activity in human colon cancer cells. These results indicate that GDNF enhances the migration of colon cancer cells by increasing VEGF-VEGFR interaction, which is mainly regulated by the p38, PI3K/Akt, and HIF1α signaling pathways.

Prognostic value and clinicopathological differences of HIFs in colorectal cancer: evidence from meta-analysis

Background

The prognostic value of HIFs in colorectal cancer was evaluated in a large number of studies, but the conclusions were inconclusive. Meanwhile, clinicopathologic differences of HIF-1α and HIF-2α were rarely compared in recent studies.

Methodology

Identical search strategies were used to search relevant literatures in the PubMed and Web of Science databases. The prognostic significances and clinicopathological differences of HIFs in CRC were analyzed.

Principal Findings

A total of 23studies comprising 2984 CRC patients met the inclusion criteria. The results indicated that overexpressed HIFs were significantly associated with increase of mortality risk, including overall survival (OS) (HR 2.06 95%CI 1.55–2.74) and disease free survival (HR 2.84, 95%CI 1.87–4.31). Subgroup analysis revealed that both overexpressed HIF-1α and HIF-2α had correlations with worse prognosis. The pooled HRs were 2.01 (95% CI: 1.55–2.6) and 2.07(95% CI: 1.01–4.26). Further subgroup analysis on HIF-1α was performed by study location, number of patients, quality score and cut-off value. The results showed that HIF-1α overexpression was significantly associated with poor OS, particularly in Asian countries (HR 2.3, 95% CI: 1.74–3.01), while not in European or other countries. In addition, overexpression of HIF-1α was closely related with these clinicopathological features, including Dukes' stages (OR 0.39, 95% CI: 0.17–0.89), UICC stages (OR 0.42 95% CI: 0.3–0.59), depth of invasion (OR 0.71, 95% CI: 0.51–0.99), lymphnode status (OR 0.49, 95% CI: 0.32–0.73) and metastasis (OR 0.29, 95% CI: 0.11–0.81). While overexpression of HIF-2α was only associated with grade of differentiation (OR 0.48, 95% CI: 0.29–0.81).

Conclusions

This study showed that both HIF-1α and HIF-2α overexpression were associated with an unfavorable prognosis. HIF-1α overexpression seemed to be associated with worse prognosis in Asian countries. Additionally, HIF-1α and HIF-2α indicated distinct clinicopathologic features.

Interferon-γ-induced intestinal epithelial barrier dysfunction by NF-κB/HIF-1α pathway

Interferon-γ (IFN-γ) plays an important role in intestinal barrier dysfunction. However, the mechanisms are not fully understood. As hypoxia-inducible factor-1 (HIF-1) is a critical determinant response to hypoxia and inflammation, which has been shown to be deleterious to intestinal barrier function, we hypothesized that IFN-γ induces loss of barrier function through the regulation of HIF-1α activation and function. In this study, we detected the expressions of HIF-1α and tight junction proteins in IFN-γ-treated T84 intestinal epithelial cell line. IFN-γ led to an increase of HIF-1α expression in time- and dose-dependent manners but did not change the expression of HIF-1β. The IFN-γ-induced increase in HIF-1α was associated with an activation of NF-κB. Treatment with the NF-κB inhibitor, pyrolidinedithiocarbamate (PDTC), significantly suppressed the activation of NF-κB and the expression of HIF-1α. In addition, IFN-γ also increased intestinal epithelial permeability and depletion of tight junction proteins; inhibition of NF-κB or HIF-1α prevented the increase in intestinal permeability and alteration in tight junction protein expressions. Interestingly, we demonstrated that a significant portion of IFN-γ activation NF-kB and modulation tight junction expression is mediated through HIF-1α. Taken together, this study suggested that IFN-γ induced the loss of epithelial barrier function and disruption of tight junction proteins, by upregulation of HIF-1α expression through NF-κB pathway.

Glucose transporter 1 (GLUT1) of anaerobic glycolysis as predictive and prognostic values in neoadjuvant chemoradiotherapy and laparoscopic surgery for locally advanced rectal cancer

PURPOSE

We investigated the relationships between biomarkers related to anaerobic glycolytic metabolism (GLUT1, LDH5, PDK1, and HIF-1α proteins), pathologic response, and prognosis.

METHODS

All stage II and stage III rectal cancer patients had 50.4 Gy (1.8 Gy/day in 28 fractions) over 5.5 weeks, plus 5-fluorouracil (425 mg/m(2)/day) and leucovorin (20 mg/m(2)/day) bolus on days 1 to 5 and 29 to 33, and surgery was performed at 7 to 10 weeks after completion of all therapies. Expression of GLUT1, LDH5, PDK1, and HIF-1α proteins was determined by immunohistochemistry and was assessed in 104 patients with rectal cancer treated with neoadjuvant chemoradiotherapy.

RESULTS

This study included stage II and III rectal cancer patients, and each stage accounted for each 50 % of the total cases. A high expression of GLUT1 protein was associated with a significantly lower rate of ypCR compared with low expression of GLUT1 protein (4.0 % vs. 27.8 %, respectively; p = 0.012). GLUT1 expression was also significantly higher in the poor response group (Grade 0, 1) than in the good response group (Grade 2, 3) (34.0 % vs. 14.8 %, respectively; p = 0.022). In recurrence analysis, the expression of GLUT1 protein demonstrated a significant correlation with time to recurrence, based on a log-rank method (p = 0.016). When analyzed by multiple Cox regression, the positive expression of GLUT1 was the most significant and independent unfavorable prognostic factor (p = 0.004).

CONCLUSIONS

GLUT1 expression is a predictive and prognostic factor for pathologic complete response and recurrence in rectal cancer patients treated with 5-flurouracil and leucovorin neo-adjuvant chemoradiotherapy.

Phase I study of 5-fluorouracil, leucovorin and bevacizumab in combination with radiation therapy in patients with locally advanced rectal cancer

A phase I clinical study was conducted to determine the maximum tolerated dose (MTD) and recommended dose (RD) of the standard treatment of 5-fluorouracil/l-leucovorin (5-FU/LV) with bevacizumab, in combination with radiation therapy in patients with locally advanced rectal cancer. Eligible patients had previously untreated stage T3 or T4 locally advanced rectal cancer. Patients received radiotherapy to the pelvis, at a total dose of 45 Gy in 25 fractions. During radiotherapy, patients received three courses of a simplified LV and 5-FU regimen (sLV5FU2), in combination with bevacizumab. Bevacizumab was infused at a fixed dose of 5 mg/kg on Days 1, 15 and 29. The sLV5FU2 regimen consisted of 200 mg/m² of LV administered by continuous intravenous (i.v.) infusion over 2 h, followed by 400 mg/m² of 5-FU administered by i.v. bolus injection, delivered at an initial loading dose of 2,000 mg/m² over 46 h. The dose was gradually increased to determine the MTD and RD of this regimen. Of the patients enrolled in the study, two developed Grade 3 diarrhea and one developed Grade 3 neutropenia. Since dose-limiting toxicity (DLT) occurred in two out of the six patients, 5-FU at a dose of 2,000 mg/m² over 46 h was determined as the MTD and designated as the RD, taking into consideration the toxicities in matched patients who received standard preoperative chemoradiotherapy with sLV5FU2 during the same period. The combination of 5-FU, LV, bevacizumab and radiotherapy in patients with locally advanced rectal cancer was found to be tolerable, with encouraging response rates. Further investigation is required in a phase II setting.

Single nucleotide polymorphisms in the HIF-1α gene and chemoradiotherapy of locally advanced rectal cancer

The aim of this study was to investigate the predictive impact of polymorphisms in the HIF-1α gene on the response to chemoradiotherapy (CRT) in rectal cancer. This study included two cohorts of patients with locally advanced rectal cancer receiving long-course CRT. The HIF-1α C1772T (rs11549465), G1790A (rs11549467) and c(*)191T>C (rs2057482) polymorphisms were investigated in the test cohort (n=65), and HIF-1α c(*)191T>C was analysed in the validation cohort (n=198). No correlations were identified between the polymorphisms and clinicopathological factors. The HIF-1α C1772T and HIF-1α G1790A polymorphisms demonstrated no correlation with tumour response to CRT in the test cohort. The HIF-1α c(*)191T>C CC genotype was marginally associated with a higher rate of complete tumour response (P=0.05) in the test cohort, while the HIF-1α c(*)191T>C CC genotype was associated with a poor tumour response (P=0.03) in the validation cohort. In conclusion, these results suggest that HIF-1α polymorphisms have no value as predictors of response to neoadjuvant CRT in rectal cancer. The results of the HIF-1α c(*)191T>C in two cohorts differ and emphasise the importance of biomarker validation.

Hypoxia-related proteins in patients with rectal cancer undergoing neoadjuvant combined modality therapy

BACKGROUND

We have previously demonstrated the prognostic significance of rectal cancer pathologic response to neoadjuvant chemoradiation. Recent studies in other cancers have reported that hypoxia influences response to neoadjuvant chemoradiation.

OBJECTIVE

This study aimed to 1) characterize hypoxia-related protein expression in locally advanced rectal cancer before neoadjuvant chemoradiation, 2) determine the comodulation of hypoxia-related protein expression, and 3) evaluate the relationship between hypoxia-related protein expression and overall survival, time to recurrence, and tumor regression grade.

DESIGN

Immunohistochemical analysis of 4 hypoxia-related proteins (HIF-1α, CA-IX, VEGF, and GLUT-1) was performed on archival pretreatment rectal cancer biopsies.

PATIENTS

: Eighty-five patients with locally advanced rectal cancer treated with neoadjuvant radiation and 5-fluorouracil-based chemotherapy were included.

MAIN OUTCOME MEASURES

The impact of hypoxia-related protein expression on outcome was evaluated by use of Cox proportional hazards model. Hypoxia-related protein expression was correlated with tumor regression grade by use of Spearman correlation coefficients.

RESULTS

Median follow-up was 54 months. CA-IX expression was associated with overall survival (p = 0.01). HIF-1α expression was weakly correlated with VEGF (r = 0.26, p = 0.02) and GLUT-1 (r = 0.35, p = 0.001). Hypoxia-related protein expression was not associated with time to recurrence or Mandard tumor regression grade.

CONCLUSIONS

Elevated CA-IX expression may be associated with poorer overall survival in locally advanced rectal cancer treated by neoadjuvant chemoradiation and resection. The expression of the hypoxia-related proteins HIF-1α, VEGF, and GLUT-1 may be comodulated in locally advanced rectal cancer. Further studies are needed to evaluate the mechanisms governing hypoxia regulation and the role of hypoxia in rectal cancer response to neoadjuvant chemoradiation.

Progress in rectal cancer treatment

The dramatic improvement in local control of rectal cancer observed during the last decades is to be attributed to attention to surgical technique and to the introduction of neoadjuvant therapy regimens. Nevertheless, systemic relapse remains frequent and is currently insufficiently addressed. Intensification of neoadjuvant therapy by incorporating chemotherapy with or without targeted agents before the start of (chemo)radiation or during the waiting period to surgery may present an opportunity to improve overall survival. An increasing number of patients can nowadays undergo sphincter preserving surgery. In selected patients, local excision or even a "wait and see" approach may be feasible following active neoadjuvant therapy. Molecular and genetic biomarkers as well as innovative imaging techniques may in the future allow better selection of patients for this treatment option. Controversy persists concerning the selection of patients for adjuvant chemotherapy and/or targeted therapy after neoadjuvant regimens. The currently available evidence suggests that in complete pathological responders long-term outcome is excellent and adjuvant therapy may be omitted. The results of ongoing trials will help to establish the ideal tailored approach in resectable rectal cancer.

Response prediction in the multimodality therapy of locally advanced rectal cancer

SUMMARY Neoadjuvant therapies have been established in the multimodality treatment of locally advanced rectal cancer. Radiation with concurrent 5-fluorouracil-based chemotherapy followed by surgical resection is considered to be the standard of care in advanced rectal cancer. However, recent studies revealed that patients with complete histopathologic response seem to benefit most from neoadjuvant therapies. Consequently, predictive markers to allow individualization of multimodality therapy in locally advanced rectal cancer are mostly required to identify those who will benefit the most. Unfortunately, there is still an immense lack of factors for response assessment in patients with rectal cancer undergoing multimodality treatment. While conventional diagnostic tools lack sufficient accuracy to provide information for response assessment, newer techniques such as [18F]-fluorodeoxyglucose-PET and diffusion-weighted MRI show promising results. In addition, studies on molecular factors for response assessment in rectal cancer are encouraging but still do not provide a reliable instrument for utilization in clinical practice.

Stem cells, quiescence and rectal carcinoma: an unexplored relationship and potential therapeutic target

Stem cells are responsible for maintaining differentiated cell numbers during normal physiology and at times of tissue stress. They have the unique capabilities of proliferation, self-renewal, clonogenicity and multi-potentiality. It is a widely held belief that stem-like cells, known as cancer stem cells (CSCs), maintain tumours. The majority of currently identified intestinal stem cell populations appear to be rapidly cycling. However, quiescent stem cell populations have been suggested to exist in both normal intestinal crypts and tumours. Quiescent CSCs may have particular significance in the modern management of colorectal cancer making their identification and characterisation a priority. In this review, we discuss the current evidence surrounding the identification and microenvironmental control of stem cell populations in intestinal crypts and tumours as well as exploring the evidence supporting the existence of a quiescent stem and CSC population in the gut and other tissues.

Progress in understanding the relationship between vascular endothelial growth factor and digestive tumors

Digestive tumors account for a large portion of human malignancies, and their incidence and mortality are on the rise. Neovascularization plays a critical role in the metastasis of tumors. Vascular endothelial growth factor (VEGF) is one of the best characterized angiogenic regulators. There is close relationship between VEGF and tumor growth, invasion and metastasis. VEGF has become a research hot for diagnosis, targeted therapy and prognosis of tumors. The purpose of this review is to review the recent progress in understanding the relationship between VEGF and digestive tumors.

Predictive factors of the response of rectal cancer to neoadjuvant radiochemotherapy

Locally advanced rectal cancer is currently treated with pre-operative radiochemotherapy (pRCT), but the response is not uniform. Identification of patients with higher likelihood of responding to pRCT is clinically relevant, as patients with resistant tumors could be spared exposure to radiation or DNA-damaging drugs that are associated with adverse side effects. To highlight predictive biomarkers of response to pRCT, a systematic search of PubMed was conducted with a combination of the following terms: "rectal", "predictive", "radiochemotherapy", "neoadjuvant", "response" and "biomarkers". Genetic polymorphisms in epithelial growth factor receptor (EGFR) and thymidylate synthase (TS) genes, the expression of several markers, such as EGFR, bcl-2/bax and cyclooxygenase (COX)-2, and circulating biomarkers, such as serum carcinoembryonic antigen (CEA) level, are promising as predictor markers, but need to be further evaluated. The majority of the studies did not support the predictive value of p53, while the values of Ki-67, TS and p21 is still controversial. Gene expression profiles of thousands of genes using microarrays, microRNA studies and the search for new circulating molecules, such as human telomerase reverse transcriptase mRNA and cell-free DNA, are providing interesting results that might lead to the identification of new useful biomarkers. Evaluation of biomarkers in larger, prospective trials are required to guide therapeutic strategies.

Interleukin-24 is correlated with differentiation and lymph node numbers in rectal cancer

AIM: To assess the significance of interleukin (IL)-24 and vascular endothelial growth factor (VEGF) expression in lymph-node-positive rectal cancer.

METHODS: Between 1998 and 2005, 90 rectal adenocarcinoma patients with lymph node involvement were enrolled. All patients received radical surgery and postoperative pelvic chemoradiotherapy of 50.4-54.0 Gy. Chemotherapy of 5-fluorouracil and leucovorin or levamisole was given intravenously during the first and last week of radiotherapy, and then monthly for about 6 mo. Expression of IL-24 and VEGF was evaluated by immunohistochemical staining of surgical specimens, and their relations with patient characteristics and survival were analyzed. The median follow-up of surviving patients was 73 mo (range: 52-122 mo).

RESULTS: IL-24 expression was found in 81 out of 90 patients; 31 showed weak intensity and 50 showed strong intensity. VEGF expression was found in 64 out of 90 patients. Negative and weak intensities of IL-24 expression were classified as negative expression for analysis. IL-24 expression was significantly reduced in poorly differentiated tumors in comparison with well or moderately differentiated tumors (P = 0.004), N2b to earlier N stages (P = 0.016), and stage IIIc to stage IIIa or IIIb (P = 0.028). The number of involved lymph nodes was also significantly reduced in IL-24-positive patients in comparison with IL-24-negative ones.There was no correlation between VEGF expression and patient characteristics. Expression of IL-24 and VEGF was not correlated with survival, but N stage and stages were significantly correlated with survival.

CONCLUSION: IL-24 expression was significantly correlated with histological differentiation, and inversely correlated with the degree of lymph node involvement in stage III rectal cancer.