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

GLUT-1 may predict metastases and death in patients with locally advanced rectal cancer

Introduction

Glucose transporter-1 (GLUT-1) has been studied as a possible predictor for survival outcomes in locally advanced rectal cancer (LARC).

Methods

We aimed to investigate the prognostic role of GLUT-1 in LARC using the data of 208 patients with clinical T3-4 stage and/or node-positive rectal adenocarcinoma, all of whom underwent neoadjuvant chemoradiotherapy (CRT) and subsequent total mesorectal excision (TME). Both pre-CRT and post-CRT specimens were immunohistologically stained for GLUT-1. Patients were classified into GLUT-1-positive and GLUT-1-negative groups and distant metastasis-free survival (DMFS) and overall survival (OS) was analyzed and compared.

Results

At a median follow-up of 74 months, post-CRT GLUT-1 status showed a significant correlation with worse DMFS (p=0.027, HR 2.26) and OS (p=0.030, HR 2.30). When patients were classified into 4 groups according to yp stage II/III status and post-CRT GLUT-1 positivity [yp stage II & GLUT-1 (-), yp stage II & GLUT-1 (+), yp stage III & GLUT-1 (-), yp stage III & GLUT-1 (+)], the 5-year DMFS rates were 92.3%, 63.9%, 65.4%, and 46.5%, respectively (p=0.013). GLUT-1 (-) groups showed markedly better outcomes for both yp stage II and III patients compared to GLUT-1 (+) groups. A similar tendency was observed for OS.

Discussion

In conclusion, post-CRT GLUT-1 may serve as a prognostic marker in LARC.

Genomic and transcriptomic determinants of response to neoadjuvant therapy in rectal cancer

The incidence of rectal cancer is increasing in patients younger than 50 years. Locally advanced rectal cancer is still treated with neoadjuvant radiation, chemotherapy and surgery, but recent evidence suggests that patients with a complete response can avoid surgery permanently. To define correlates of response to neoadjuvant therapy, we analyzed genomic and transcriptomic profiles of 738 untreated rectal cancers. APC mutations were less frequent in the lower than in the middle and upper rectum, which could explain the more aggressive behavior of distal tumors. No somatic alterations had significant associations with response to neoadjuvant therapy in a treatment-agnostic manner, but KRAS mutations were associated with faster relapse in patients treated with neoadjuvant chemoradiation followed by consolidative chemotherapy. Overexpression of IGF2 and L1CAM was associated with decreased response to neoadjuvant therapy. RNA-sequencing estimates of immune infiltration identified a subset of microsatellite-stable immune hot tumors with increased response and prolonged disease-free survival.

Correlation of 18F-FDG/PET SUVmax, SUVmean, MTV, and TLG with HIF-1α in Patients with Colorectal Cancer

Objectives:

Post-hypoxia hypoxia-inducible factor (HIF)-1α activation plays a vital role in colorectal cancer (CRC) angiogenesis. Although glucose metabolism is induced in some cancer types via HIF-1α, the prognostic significance of HIF-1α in CRC and its correlation with ¹⁸fluorinefluorodeoxyglucose (¹⁸F-FDG) uptake in positron emission tomography (PET) remain controversial. This study aims to investigate the association between ¹⁸F-FDG/PET parameters and HIF-1α expression in CRC.

Methods:

Thirty-six histopathologically confirmed patients with CRC who had ¹⁸F-FDG/PET scans before surgery were enrolled in the study. The correlations between the maximum standardized uptake value (SUV_max), SUV_mean, metabolic tumor volume (MTV), total lesion glycolysis, HIF-1α overexpression, and histopathological features were evaluated.

Results:

The tumor location, tumor diameter, perineural invasion, lymphovascular invasion, T and N stage were not significantly correlated with HIF-1α overexpression. In contrast, the tumor differentiation was negatively correlated with HIF-1α expression (r=-0.332, p=0.048). None of the ¹⁸F-FDG/PET parameters was significantly correlated with HIF-1α overexpression. A significant relationship was found between tumor differentiation, tumor necrosis percentage, and MTV (p=0.030, p=0.020).

Conclusion:

The expected association between HIF-1α overexpression and ¹⁸F-FDG/PET parameters was not found in this study. However, there was a relationship between MTV, tumor differentiation, and tumor necrosis percentage. Hence, further studies are required to predict the pathological and prognostic courses of CRC using a diagnostic ¹⁸F-FDG/PET evaluation.

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.

Relationships between hypoxia induced factor-1α and 18F-FDG PET/CT parameters in colorectal cancer

AIM

The hypoxia-inducible factor 1 (HIF-1) has a critical role in oxygen homeostasis and it is a transcriptional activator of angiogenesis, erythropoiesis, iron and glucose metabolism. Glucose metabolism rate is increased in some tumours via HIF-1α. Our aim is to evaluate the relationship between hypoxia in colorectal cancer, PET parameters, necrotic tissue size and pathologic prognostic factors via using HIF-1α.

MATERIALS/METHODS

70 patients (28 female/42 male; median age: 63 years) who were diagnosed with colorectal cancer via biopsy were staged with preoperative PET/CT and operated subsequently. Immunohistochemical evaluation scoring was done according to nuclear HIF-1α expression, staining density and intensity. Metabolic tumour volume (MTV), total lesion glycolysis (TLG) and tumour volume (TV) were calculated by using volume of an ellipsoid formula via CT images, and percentage of tumour necrosis (%TmNcr) that was calculated by the difference between TV and recorded MTV.

RESULTS

There was a moderately meaningful positive correlation between tumour SUVmax and TV and %TmNcr (r=0.403, p=0.001 and r=0.500, p=0.0001, respectively). There were no statistically significant relationships between HIF-1α expression levels and tumour SUVmax, TLG, MTV, TV, %TmNcr, tumour stage, lymphovascular invasion, perineural invasion and extracapsular/capsular lymph node involvement. On the other hand, strong nuclear immunohistochemical staining was seen in tumour cells adjacent to invasive border, inflammatory cells. Although not statistically significant, moderate or strong nuclear staining were seen in 64.9% of metastatic patients.

CONCLUSION

Although the presence of a positive correlation between tumour SUVmax and %TmNcr shows that there are hypoxic cells in cancer tissue with high FDG uptake, the relationship between the presence of HIF-1α and enhanced glucose metabolism and pathological prognostic factors of tumour was not shown. Strong nuclear immunohistochemical staining in tumour cells adjacent to invasive border and inflammatory cells leads us to believe that HIF-1α plays a role in the invasion area of tumour microenvironment.

An experimental strategy unveiling exosomal microRNAs 486-5p, 181a-5p and 30d-5p from hypoxic tumour cells as circulating indicators of high-risk rectal cancer

Tumour hypoxia contributes to poor treatment outcome in locally advanced rectal cancer (LARC) and circulating extracellular vesicles (EVs) as potential biomarkers of tumour hypoxia and adverse prognosis have not been fully explored. We examined EV miRNAs from hypoxic colorectal cancer cell lines as template for relevant miRNAs in LARC patients participating in a prospective biomarker study (NCT01816607). Five cell lines were cultured under normoxia (21% O₂) or hypoxia (0.2% O₂) for 24 h, and exosomes were isolated by differential ultracentrifugation. Using a commercial kit, exosomes were precipitated from 24 patient plasma samples collected at the time of diagnosis. Exosome size distribution and protein cargo were determined by cryo-electron microscopy, nanoparticle tracking analysis, immunoblotting and flow cytometry. The vesicles harboured strong cell line-specific miRNA profiles with 35 unique miRNAs differentially expressed between hypoxic and normoxic cells. Six of these miRNAs were considered candidate-circulating markers of tumour hypoxia in the patients based on the frequency or magnitude of variance in hypoxic versus normoxic cell line experiments and prevalence in patient plasma. Of these, low plasma levels of exosomal miR-486-5p and miR-181a-5p were associated with organ-invasive primary tumour (p = 0.029) and lymph node metastases (p = 0.024), respectively, both attributes of adverse LARC prognosis. In line with this, the plasma level of exosomal miR-30d-5p was elevated in patients who experienced metastatic progression (p = 0.036). Our strategy confirmed that EVs from colorectal cancer cell lines were exosomes containing the oxygen-sensitive miRNAs 486-5p, 181a-5p and 30d-5p, which were retrieved as circulating markers of high-risk LARC.

Targeting Strategies for Glucose Metabolic Pathways and T Cells in Colorectal Cancer

Colorectal cancer is a heterogeneous group of diseases that result from the accumulation of different sets of genomic alterations, together with epigenomic alterations, and it is influenced by tumor-host interactions, leading to tumor cell growth and glycolytic imbalances. This review summarizes recent findings that involve multiple signaling molecules and downstream genes in the dysregulated glycolytic pathway. This paper further discusses the role of the dysregulated glycolytic pathway in the tumor initiation, progression and the concomitant systemic immunosuppression commonly observed in colorectal cancer patients. Moreover, the relationship between colorectal cancer cells and T cells, especially CD8+ T cells, is discussed, while different aspects of metabolic pathway regulation in cancer cell proliferation are comprehensively defined. Furthermore, this study elaborates on metabolism in colorectal cancer, specifically key metabolic modulators together with regulators, glycolytic enzymes, and glucose deprivation induced by tumor cells and how they inhibit T-cell glycolysis and immunogenic functions. Moreover, metabolic pathways that are integral to T cell function, differentiation, and activation are described. Selective metabolic inhibitors or immunemodulation agents targeting these pathways may be clinically useful to increase effector T cell responses for colorectal cancer treatment. However, there is a need to identify specific antigens using a cancer patient-personalized approach and combination strategies with other therapeutic agents to effectively target tumor metabolic pathways.

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.

Selecting patients for hyperthermia combined with preoperative chemoradiotherapy for locally advanced rectal cancer

BACKGROUND

This study investigated the role of hyperthermia combined with preoperative concurrent chemoradiotherapy (CCRT) for locally advanced rectal cancer (LARC) according to hypoxic marker expression.

METHODS

One hundred and nine LARC patients with tissue blocks available for immunohistochemical assessment of carbonic anhydrase 9 (CA9) expression were reviewed. CA9 expression was considered positive when the staining percentage of tumor cells was >25% (n = 31). Pelvic radiotherapy with a total dose of 39.6-45 Gy was delivered concurrently with fluorouracil-based chemotherapy. Hyperthermia was administered to 52 patients twice a week during CCRT. Treatment response and outcomes were compared between hyperthermochemoradiotherapy (HCRT) and CCRT groups.

RESULTS

In patients with positive CA9 expression, the rates of downstaging (p = 0.060) and pathologic complete response (p = 0.064) tended to be higher in the HCRT group than in the CCRT group. Distant metastasis-free survival (p = 0.029) and cancer-specific survival (p = 0.020) were significantly worse in tumors with both positive CA9 expression and poor tumor response. Negative CA9 expression, presence of major tumor response, and the use of hyperthermia were significant favorable prognostic factors for cancer-specific survival after the first recurrence in multivariate analysis.

CONCLUSIONS

Hyperthermia might selectively enhance the preoperative treatment response in LARC with positive CA9 expression and offset the negative effect of hypoxia on prognosis. Pretreatment evaluation of hypoxia could aid in the selection of patients who might benefit from hyperthermia.

KRAS/BRAF基因与结肠癌糖代谢研究现状

正电子发射断层成像术(positron emission tomography, PET)/计算机断层扫描(computed tomography, CT)显像可用于结肠癌的诊断、监测疗效和预后评估. ¹⁸F标记葡萄糖(2-fluorine-18-fluoro-2-deeoxy-D-glucose, ¹⁸F-FDG)是PET/CT常用显像剂, 可以反映结肠癌活体组织葡萄糖代谢. KRAS/BRAF基因检测常用于结肠癌靶向治疗方案的选择及评估其治疗效果. 文献报道¹⁸F-FDG-PET/CT显像可预测结肠癌KRAS/BRAF基因状态, 能以无创的方式预测结肠癌抗表皮生长因子受体靶向治疗效果. 目前国内有关KRAS/BRAF基因与结肠癌糖代谢的研究相对较少, 本文结合近期的相关文献进行概述.

Mechanisms underlying 18F-fluorodeoxyglucose accumulation in colorectal cancer

Positron emission tomography (PET) with ¹⁸F-fluorodeoxyglucose (FDG) is a diagnostic tool to evaluate metabolic activity by measuring accumulation of FDG, an analogue of glucose, and has been widely used for detecting small tumors, monitoring treatment response and predicting patients’ prognosis in a variety of cancers. However, the molecular mechanism of FDG accumulation into tumors remains to be investigated. It is well-known that most cancers are metabolically active with elevated glucose metabolism, a phenomenon known as the Warburg effect. The underlying mechanisms for elevated glucose metabolism in cancer tissues are complex. Recent reports have indicated the potential of FDG-PET/CT scans in predicting mutational status (e.g., KRAS gene mutation) of colorectal cancer (CRC), which suggests that FDG-PET/CT scans may play a key role in determining therapeutic strategies by non-invasively predicting treatment response to anti-epidermal growth factor receptor (EGFR) therapy. In this review, we summarize the current findings investigating the molecular mechanism of ¹⁸F-FDG accumulation in CRC.

Dexamethasone downregulates expression of carbonic anhydrase IX via HIF-1α and NF-κB-dependent mechanisms

Dexamethasone is a synthetic glucocorticoid frequently used to suppress side-effects of anticancer chemotherapy. In the present study, we showed that dexamethasone treatment leads to concentration-dependent downregulation of cancer-associated marker, carbonic anhydrase IX (CA IX), at the level of promoter activity, mRNA and protein expression in 2D and 3D cancer cell models. The effect of dexamethasone on CA IX expression under hypoxic conditions is predominantly mediated by impaired transcriptional activity and decreased protein level of the main hypoxic transcription factor HIF-1α. In addition, CA9 downregulation can be caused by protein-protein interactions between activated glucocorticoid receptors, major effectors of glucocorticoid action, and transcription factors that trigger CA9 transcription (e.g. AP-1). Moreover, we identified a potential NF-κB binding site in the CA9 promoter and propose the involvement of NF-κB in the dexamethasone-mediated inhibition of CA9 transcription. As high level of CA IX is often linked to aggressive tumor behavior, poor prognosis and chemo- and radiotherapy resistance, uncovering its reduction after dexa-methasone treatment and implication of additional regulatory mechanisms can be relevant for the CA IX-related clinical applications.

Prognostic Significance of Carbonic Anhydrase IX Expression in Cancer Patients: A Meta-Analysis

Hypoxia is a characteristic of many solid tumors and an adverse prognostic factor for treatment outcome. Hypoxia increases the expression of carbonic anhydrase IX (CAIX), an enzyme that is predominantly found on tumor cells and is involved in maintaining the cellular pH balance. Many clinical studies investigated the prognostic value of CAIX expression, but most have been inconclusive, partly due to small numbers of patients included. The present meta-analysis was therefore performed utilizing the results of all clinical studies to determine the prognostic value of CAIX expression in solid tumors. Renal cell carcinoma was excluded from this meta-analysis due to an alternative mechanism of upregulation. 958 papers were identified from a literature search performed in PubMed and Embase. These papers were independently evaluated by two reviewers and 147 studies were included in the analysis. The meta-analysis revealed strong significant associations between CAIX expression and all endpoints: overall survival [hazard ratio (HR) = 1.76, 95% confidence interval (95%CI) 1.58–1.98], disease-free survival (HR = 1.87, 95%CI 1.62–2.16), locoregional control (HR = 1.54, 95%CI 1.22–1.93), disease-specific survival (HR = 1.78, 95%CI 1.41–2.25), metastasis-free survival (HR = 1.82, 95%CI 1.33–2.50), and progression-free survival (HR = 1.58, 95%CI 1.27–1.96). Subgroup analyses revealed similar associations in the majority of tumor sites and types. In conclusion, these results show that patients having tumors with high CAIX expression have higher risk of locoregional failure, disease progression, and higher risk to develop metastases, independent of tumor type or site. The results of this meta-analysis further support the development of a clinical test to determine patient prognosis based on CAIX expression and may have important implications for the development of new treatment strategies.

Early increase in circulating carbonic anhydrase IX during neoadjuvant treatment predicts favourable outcome in locally advanced rectal cancer

Background

Locally advanced rectal cancer (LARC) comprises heterogeneous tumours with predominant hypoxic components. The hypoxia-inducible metabolic shift causes microenvironmental acidification generated by carbonic anhydrase IX (CAIX) and facilitates metastatic progression, the dominant cause of failure in LARC.

Methods

Using a commercially available immunoassay, circulating CAIX was assessed in prospectively archived serial serum samples collected during combined-modality neoadjuvant treatment of LARC patients and correlated to histologic tumour response and progression-free survival (PFS).

Results

Patients who from their individual baseline level displayed serum CAIX increase above a threshold of 224 pg/ml (with 96 % specificity and 39 % sensitivity) after completion of short-course neoadjuvant chemotherapy (NACT) prior to long-course chemoradiotherapy and definitive surgery had significantly better 5-year PFS (94 %) than patients with below-threshold post-NACT versus baseline alteration (PFS rate of 56 %; p < 0.01). This particular CAIX parameter, ΔNACT, was significantly correlated with histologic ypT0–2 and ypN0 outcome (p < 0.01) and remained an independent PFS predictor in multivariate analysis wherein it was entered as continuous variable (p = 0.04).

Conclusions

Our results indicate that low ΔNACT, i.e., a weak increase in serum CAIX level following initial neoadjuvant treatment (in this case two cycles of the Nordic FLOX regimen), might be used as risk-adapted stratification to postoperative therapy or other modes of intensification of the combined-modality protocol in LARC.

Trial registration

ClinicalTrials.gov NCT00278694

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1557-6) contains supplementary material, which is available to authorized users.

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.

Expression of hypoxic marker carbonic anhydrase IX predicts poor prognosis in resectable hepatocellular carcinoma

Carbonic anhydrase IX (CA-IX), a hypoxia marker, correlates with tumor progression in a variety of human cancers. However, the role of CA-IX in hepatocellular carcinomas (HCCs) remains largely unknown. We examined the expression of 277 unifocal, resectable, primary HCC tumors using immunohistochemistry. The CA-IX protein was expressed in 110 of the 227 (48.5%) HCC tumors. The expression of CA-IX correlated with younger age (P = 0.0446), female sex (P = 0.0049), high serum α-fetoprotein levels (P<1x10^-6), larger tumor size (P = 0.0031), high tumor grade P<1x10^-6) and high tumor stage (P = 1.5x10^-6). Patients with HCC tumors that expressed CA-IX were more likely to have lower 5-year disease-free survival (DFS; P = 0.0001) and 5-year overall survival (OS; P<1x10^-6). The multivariate analysis indicated that CA-IX expression was an independent predictor for high tumor stage (P = 0.0047) and DFS (P = 0.0456), and a borderline predictor for OS (P = 0.0762). Furthermore, CA-IX expression predicted poor DFS and OS in patients with high tumor stage (P = 0.0004 and P<1x10^-6, respectively). Interestingly, CA-IX expression might contribute to the worse prognosis of female patients with advanced HCCs. Our study indicates the expression of the CA-IX protein is a crucial predictor of poor prognosis in resectable HCC, and it is also an unfavorable prognostic predictor in HCC patients with high tumor stage.

Upregulation of stromal cell-derived factor 1α expression is associated with the resistance to neoadjuvant chemoradiotherapy of locally advanced rectal cancer: angiogenic markers of neoadjuvant chemoradiation

The ability to achieve pathologic downstaging after neoadjuvant chemoradiotherapy (NCRT) is correlated with improved survival in locally advanced rectal cancer (LARC). However, there is no effective predictive markers. In this study, the expression of angiogenic markers was evaluated in pre-treatment biopsies and corresponding post-treatment resection specimens, and were correlated to histopathological tumour characteristics and response. Fifty-five patients with stage II/III rectal cancer treated with 5-fluorouracil (5-FU)-based NCRT were studied. All patients were administered NCRT followed by surgical resection. Immunohistochemical staining for angiogenic markers [hypoxia-inducible factor 1α (HIF‑1α), vascular endothelial growth factor (VEGF), stromal cell‑derived factor 1α (SDF-1α) and placental growth factor (PlGF)] was performed on specimens obtained before NCRT and after surgery. Expression of VEGF, PlGF and HIF-1α protein was downregulated after NCRT in the rectal cancer tissues (P<0.001, P=0.001 and P=0.044, respectively). However, SDF-1α was upregulated after NCRT (P<0.001). Moreover, upregulated expression of SDF-1α (P=0.016) and positive PlGF staining (P=0.001) after NCRT were significantly associated with resistance to NCRT. On multivariate analysis, positive PlGF staining after NCRT was found to be independently associated with resistance to NCRT (P=0.013). Our data suggest that SDF-1α and PlGF should be evaluated as new targets for NCRT in LARC.

Hypoxia-induced carbonic anhydrase IX as a target for cancer therapy: from biology to clinical use

The tumor microenvironment includes a complicated network of physiological gradients contributing to plasticity of tumor cells and heterogeneity of tumor tissue. Hypoxia is a key component generating intratumoral oxygen gradients, which affect the cellular expression program and lead to therapy resistance and increased metastatic propensity of weakly oxygenated cell subpopulations. One of the adaptive responses of tumor cells to hypoxia involves the increased expression and functional activation of carbonic anhydrase IX (CA IX), a cancer-related cell surface enzyme catalyzing the reversible conversion of carbon dioxide to bicarbonate ion and proton. Via its catalytic activity, CA IX participates in regulation of intracellular and extracellular pH perturbations that result from hypoxia-induced changes in cellular metabolism producing excess of acid. Through the ability to regulate pH, CA IX also facilitates cell migration and invasion. In addition, CA IX has non-catalytic function in cell adhesion and spreading. Thus, CA IX endows tumor cells with survival advantages in hypoxia/acidosis and confers an increased ability to migrate, invade and metastasize. Accordingly, CA IX is expressed in a broad range of tumors, where it is associated with prognosis and therapy outcome. Its expression pattern and functional implications in tumor biology make CA IX a promising therapeutic target, which can be hit either by immunotherapy with monoclonal antibodies or with compounds inhibiting its enzyme activity. The first strategy has already reached the clinical trials, whereas the second one is still in preclinical testing. Both strategies indicate that CA IX can become a clinically useful anticancer target, but urge further efforts toward better selection of patients for immunotherapy and deeper understanding of tumor types, clinical situations and synthetic lethality interactions with other treatment approaches.

DPYD, TYMS, TYMP, TK1, and TK2 genetic expressions as response markers in locally advanced rectal cancer patients treated with fluoropyrimidine-based chemoradiotherapy

This study is to investigate multiple chemotherapeutic agent- and radiation-related genetic biomarkers in locally advanced rectal cancer (LARC) patients following fluoropyrimidine-based concurrent chemoradiotherapy (CCRT) for response prediction. We initially selected 6 fluoropyrimidine metabolism-related genes (DPYD, ORPT, TYMS, TYMP, TK1, and TK2) and 3 radiotherapy response-related genes (GLUT1, HIF-1α, and HIF-2α) as targets for gene expression identification in 60 LARC cancer specimens. Subsequently, a high-sensitivity weighted enzymatic chip array was designed and constructed to predict responses following CCRT. After CCRT, 39 of 60 (65%) LARC patients were classified as responders (pathological tumor regression grade 2 ~ 4). Using a panel of multiple genetic biomarkers (chip), including DPYD, TYMS, TYMP, TK1, and TK2, at a cutoff value for 3 positive genes, a sensitivity of 89.7% and a specificity of 81% were obtained (AUC: 0.915; 95% CI: 0.840-0.991). Negative chip results were significantly correlated to poor CCRT responses (TRG 0-1) (P = 0.014, hazard ratio: 22.704, 95% CI: 3.055-235.448 in multivariate analysis). Disease-free survival analysis showed significantly better survival rate in patients with positive chip results (P = 0.0001). We suggest that a chip including DPYD, TYMS, TYMP, TK1, and TK2 genes is a potential tool to predict response in LARC following fluoropyrimidine-based CCRT.