AACR Cancer Progress Report 2016

Unveil Intrahepatic Cholangiocarcinoma Heterogeneity through the Lens of Omics and Multi-Omics Approaches

Intrahepatic cholangiocarcinoma (iCCA) is recognized worldwide as the second leading cause of morbidity and mortality among primary liver cancers, showing a continuously increasing incidence rate in recent years. iCCA aggressiveness is revealed through its rapid and silent intrahepatic expansion and spread through the lymphatic system leading to late diagnosis and poor prognoses. Multi-omics studies have aggregated information derived from single-omics data, providing a more comprehensive understanding of the phenomena being studied. These approaches are gradually becoming powerful tools for investigating the intricate pathobiology of iCCA, facilitating the correlation between molecular signature and phenotypic manifestation. Consequently, preliminary stratifications of iCCA patients have been proposed according to their "omics" features opening the possibility of identifying potential biomarkers for early diagnosis and developing new therapies based on personalized medicine (PM). The focus of this review is to provide new and advanced insight into the molecular pathobiology of the iCCA, starting from single- to the latest multi-omics approaches, paving the way for translating new basic research into therapeutic practices.

Molecular Pathways Implicated in Radioresistance of Glioblastoma Multiforme: What Is the Role of Extracellular Vesicles?

Glioblastoma multiforme (GBM) is a primary brain tumor that is very aggressive, resistant to treatment, and characterized by a high degree of anaplasia and proliferation. Routine treatment includes ablative surgery, chemotherapy, and radiotherapy. However, GMB rapidly relapses and develops radioresistance. Here, we briefly review the mechanisms underpinning radioresistance and discuss research to stop it and install anti-tumor defenses. Factors that participate in radioresistance are varied and include stem cells, tumor heterogeneity, tumor microenvironment, hypoxia, metabolic reprogramming, the chaperone system, non-coding RNAs, DNA repair, and extracellular vesicles (EVs). We direct our attention toward EVs because they are emerging as promising candidates as diagnostic and prognostication tools and as the basis for developing nanodevices for delivering anti-cancer agents directly into the tumor mass. EVs are relatively easy to obtain and manipulate to endow them with the desired anti-cancer properties and to administer them using minimally invasive procedures. Thus, isolating EVs from a GBM patient, supplying them with the necessary anti-cancer agent and the capability of recognizing a specified tissue-cell target, and reinjecting them into the original donor appears, at this time, as a reachable objective of personalized medicine.

Nasopharyngeal carcinoma among the Bidayuh of Sarawak, Malaysia: History and risk factors

Nasopharyngeal carcinoma (NPC) is a cancer of the epithelial cells lining the nasopharynx. The incidence of NPC has a distinct geographical distribution, mainly affecting the Chinese population of Southern China. In Malaysia, this cancer is exceptionally prevalent among males. There is a high incidence rate of NPC among the Bidayuh natives in Sarawak, Malaysia. Other than epidemiology reports, there has not been an article describing plausible cancer risk factors contributing to NPC within this native group. Researchers are still trying to understand the reasons the Bidayuh and Southern Chinese are highly susceptible to NPC. This article discusses the risk factors of developing NPC: Epstein-Barr virus infection, genetic predisposition, diet, environmental exposure and tobacco smoking. There is a need to improve the understanding of the role of risk factors to identify new ways to prevent cancer, especially among high-risk groups.

Environmental DNA monitoring of oncogenic viral shedding and genomic profiling of sea turtle fibropapillomatosis reveals unusual viral dynamics

Pathogen-induced cancers account for 15% of human tumors and are a growing concern for endangered wildlife. Fibropapillomatosis is an expanding virally and environmentally co-induced sea turtle tumor epizootic. Chelonid herpesvirus 5 (ChHV5) is implicated as a causative virus, but its transmission method and specific role in oncogenesis and progression is unclear. We applied environmental (e)DNA-based viral monitoring to assess viral shedding as a direct means of transmission, and the relationship between tumor burden, surgical resection and ChHV5 shedding. To elucidate the abundance and transcriptional status of ChHV5 across early, established, regrowth and internal tumors we conducted genomics and transcriptomics. We determined that ChHV5 is shed into the water column, representing a likely transmission route, and revealed novel temporal shedding dynamics and tumor burden correlations. ChHV5 was more abundant in the water column than in marine leeches. We also revealed that ChHV5 is latent in fibropapillomatosis, including early stage, regrowth and internal tumors; higher viral transcription is not indicative of poor patient outcome, and high ChHV5 loads predominantly arise from latent virus. These results expand our knowledge of the cellular and shedding dynamics of ChHV5 and can provide insights into temporal transmission dynamics and viral oncogenesis not readily investigable in tumors of terrestrial species.

Drug development post COVID-19 pandemic: toward a better system to meet current and future global health challenges

Introduction: Despite advances in drug research and development, our knowledge of the underlying molecular mechanisms of many diseases remains inadequate. This have led to limited effective medicines for several diseases. To address these challenges, efficient strategies, novel technologies, and policies are urgently needed. The main obstacles in drug discovery and development are the mounting cost, risk, and time frame needed to develop new medicines. Fair pricing and accessibility is another unmet global challenge.Areas covered: Here, the authors cover the pace, risks, cost, and challenges facing drug development processes. Additionally, they introduce disease-associated data which demand global attention and propose solutions to overcome these challenges.Expert opinion: The massive challenges encountered during drug development urgently call for a serious global rethinking of the way this process is done. A partial solution might be if many consortiums of multi-nations, academic institutions, clinicians, pharma companies, and funding agencies gather at different fronts to crowdsource resources, share knowledge and risks. Such an ecosystem can rapidly generate first-in-class molecules that are safe, effective, and affordable. We think that this article represents a wake-up call for the scientific community to immediately reassess the current drug discovery and development procedures.

Calculated indices of volatile organic compounds (VOCs) in exhalation for lung cancer screening and early detection

BACKGROUND

Breath analysis is a promising noninvasive technique that offers a wide range of opportunities to facilitate early diagnosis of lung cancer (LC).

METHOD

Exhaled breath samples of 352 subjects including 160 with lung cancer (LC), 70 with benign pulmonary nodule (BPN) and 122 healthy controls (HC) were analyzed through thermal desorption coupled with gas chromatography-mass spectrometry (TD-GC-MS) to obtain the metabolic information from volatile organic compounds (VOCs). Statistical classification models were used to find diagnostic clusters of VOCs for the discrimination of HC, BPN and LC patients' early and advanced stages, as well as subtypes of LC. Receiver operator characteristics (ROC) curves with 5-fold validations were used to evaluate the accuracy of these models.

RESULTS

The analysis revealed that 20, 19, 19, and 20 VOCs discriminated LC from HC, LC from BPN, histology and LC stages respectively. The calculated diagnostic indices showed a large area under the curve (AUC) to distinguish HC from LC (AUC: 0.987, 95 % confidence interval (CI): 0.976-0.997), BPN from LC (AUC: 0.809, 95 % CI: 0.758-0.860), NSCLC from SCLC (AUC: 0.939, 95 % CI: 0.875-0.995) and Stage III from stage III-IV (AUC: 0.827, 95 % CI: 0.768-0.886). The comparison between the high-risk groups (BPN and HC smokers) and early stages LC resulted in the AUC of 0.756 (95 %CI: 0.681-0.817) for BPN vs. early stage LC and AUC of 0.986 (95 % CI: 0.972-0.994) for HC smoker vs. early stage LC.

CONCLUSION

Volatome of breath of the LC patients was significantly different from that of both BPN patients and HC and showed an ability of distinguishing early from advance stage LC and NSCLC from SCLC. We conclude that the volatome has a potential to help improve early diagnosis of LC.

Molecular characterization of a marine turtle tumor epizootic, profiling external, internal and postsurgical regrowth tumors

Sea turtle populations are under threat from an epizootic tumor disease (animal epidemic) known as fibropapillomatosis. Fibropapillomatosis continues to spread geographically, with prevalence of the disease also growing at many longer-affected sites globally. However, we do not yet understand the precise environmental, mutational and viral events driving fibropapillomatosis tumor formation and progression.Here we perform transcriptomic and immunohistochemical profiling of five fibropapillomatosis tumor types: external new, established and postsurgical regrowth tumors, and internal lung and kidney tumors. We reveal that internal tumors are molecularly distinct from the more common external tumors. However, they have a small number of conserved potentially therapeutically targetable molecular vulnerabilities in common, such as the MAPK, Wnt, TGFβ and TNF oncogenic signaling pathways. These conserved oncogenic drivers recapitulate remarkably well the core pan-cancer drivers responsible for human cancers. Fibropapillomatosis has been considered benign, but metastatic-related transcriptional signatures are strongly activated in kidney and established external tumors. Tumors in turtles with poor outcomes (died/euthanized) have genes associated with apoptosis and immune function suppressed, with these genes providing putative predictive biomarkers.Together, these results offer an improved understanding of fibropapillomatosis tumorigenesis and provide insights into the origins, inter-tumor relationships, and therapeutic treatment for this wildlife epizootic.

Development of new descriptor for melanoma detection on dermoscopic images

Early detection of melanoma has critical importance for the success of the treatment. However, a successful early diagnosis is only possible with the existence of discriminative features. In this study, a new descriptor based on the number of colors was developed in order to successfully diagnose lesions of melanoma. The number of colors is the main feature in the identification of melanoma-type skin lesions. The user must select a threshold value when calculating the number of colors of the lesion. The incorrect threshold value selection of non-expert users disrupts the aforementioned feature and also leads to significant diagnostic errors. In this study, it was revealed that color counting threshold values have a significant effect on the distinctiveness of the number of colors. In the three dermoscopic databases, color counting threshold values that provide the maximum distinctiveness on melanoma and benign lesions were determined as 0 and 0.123 respectively. By using these color counting threshold values, the number of colors for each sample in the data sets was calculated separately. Following that, a novel attribute called the number of color difference was defined as a function of color counting threshold values. Experiments using only the proposed new descriptor yielded 52.7% higher f-measure and 84.5% higher true-positive performance than the number of colors used in the literature. The results obtained in this study revealed the importance of accurately determining the number of colors the lesions had and states that the applied color counting threshold significantly influences the classification results. Thereby, a new method is proposed for determining the critical color counting threshold. We claim that the classical ABCD rule should be improved by our new descriptor. Graphical abstract Fig. 1 Selection of threshold has vital effect on skin lesion classification. A new method to select the correct threshold value and a new attribute for correct classification were developed.

MicroRNA‑188‑5p inhibits the progression of breast cancer by targeting zinc finger protein 91

Breast cancer (BC) is the most commonly diagnosed malignant cancer in women. BC is the main cause of cancer-related death in women and seriously threatens the life and health of women worldwide. MicroRNAs (miRNAs/miRs) have been reported to regulate the development and progression of different types of cancer. However, the regulatory functions of miR-188-5p in BC have not been thoroughly demonstrated. In this present research, we identified that miR-188-5p was downregulated in BC tissues and several BC cell lines. Downregulation of miR-188-5p was significantly associated with advanced TNM stage. Moreover, we identified that miR-188-5p mimics significantly inhibited proliferation using CCK-8 assay, colony formation and xenograft animal model, suppressed invasion and migration detected by Transwell invasion assay, and increased the cellular apoptosis of BC cells as determined by cell apoptosis assay. Moreover miR-188-5p mimics also reduced the expression of NF-κB p65(Rel). To further investigate its regulatory mechanism, transcription factor zinc finger protein 91 (ZFP91) was predicted as the targeted protein of miR-188-5p by bioinformatic method. We confirmed their specific binding by dual luciferase (DLR) assay. We demonstrated that the overexpression of miR-188-5p significantly inhibited the expression of ZFP91 in BC cell lines and reduced the expression of NF-κB p65(Rel). An inverse correlation was found between the expression of miR-188-5p and ZFP91 in BC tissues. Importantly, we demonstrated that the restoration of ZFP91 was able to block the effect of miR-188-5p on the progression of MDA-MB-231 cells. Therefore, our study showed that miR-188-5p may be one of the important indicators and could inhibit the progression of human BC via targeting the ZFP91/NF-κB p65(Rel) signaling pathway, suggesting that miR-188-5p may be a promising future target for BC treatment.

IFNβ-induced exosomal linc-EPHA6-1 promotes cytotoxicity of NK cells by acting as a ceRNA for hsa-miR-4485-5p to up-regulate NKp46 expression

AIMS

Exosomes contain functional molecules from their cells of origin and can enter recipient cells for intercellular communication. Interferon β (IFNβ) has been shown to induce some lncRNAs to regulate host immune response and play a major role in the positive regulation of the activity of natural killer (NK) cells. We aim to clarify whether IFNβ induced exosomes can regulate the cytotoxicity of NK cells by transferring specific lncRNAs into NK cells.

MAIN METHODS

Exosomes were isolated from the supernatants of A549 cells with or without IFNβ treatment. Co-culture and ELISA assay were used to analyze the effect of exosomes on the cytotoxicity of NK cells. Human transcriptome array (HTA) was performed to analyze the profiling of RNAs wrapped in exosomes. Then subcellular location, qPCR, western blotting, dual-luciferase reporter assay and ELISA were used to determine long noncoding RNAs (lcnRNAs) location, sponge absorb effects, the expression of NKp46 and cytotoxicity of NK cells.

KEY FINDINGS

ELISA assay showed IFNβ induced exosomes can strengthen the cytotoxicity of NK cells. Through HTA we found the expression levels of 69 lncRNAs were significantly changed within IFNβ induced exosomes. Additionally, we found a specific exosomal cargo, linc-EPHA6-1, acted as a competing endogenous RNA (ceRNA) for hsa-miR-4485-5p which subsequently up-regulate one of the natural cytotoxicity receptors (NKp46) expression. Furthermore, we verified over-expression of linc-EPHA6-1 significantly enhances the cytotoxicity of NK cells against A549 cells and Zika virus infected A549 cells.

SIGNIFICANCE

Our results demonstrated that IFNβ-induced exosomal linc-EPHA6-1 can regulate the cytotoxicity of NK cells.

Effect of intra- and inter-tumoral heterogeneity on molecular characteristics of primary IDH-wild type glioblastoma revealed by single-cell analysis

Aims

To reveal the effects of intra‐ and inter‐tumoral heterogeneity on characteristics of primary IDH‐wild type glioblastoma cells.

Methods

Single‐cell RNA‐seq data were acquired from the GEO database, and bulk sample transcriptome data were downloaded from the TCGA database with clinical information. Neoplastic subtype and glioma stem‐like cells (GSCs) were identified by matching 5000 random virtual samples based on ssGSEA. CNV was inferred to compare the heterogeneity among patients and subtypes by infercnv. Transition direction was inferred by RNA velocity, and lineage trajectory was inferred by monocle. Regulon network of cells was analyzed by SCENIC, and cell communication was identified by CellPhoneDB.

Results

Glioblastoma (GBM) cells could be divided into four subtypes by Verhaak classifier. However, classification of three subtypes (except NE subtype) was more suitable for GBM cells, and Verhaak classifier has difficulty in distinguishing GSCs. GBM heterogeneity and GBM cells’ regulon network were mainly influenced by inter‐tumoral heterogeneity. Within the same patient, different subclones exist in the same subtype of cells whose transition direction could be predicted by regulon similarity. Apart from inter‐tumoral heterogeneity, different subtype of cells share common subtype‐specific cell‐cell communications.

Conclusions

Inter‐tumoral heterogeneity contributes mainly to GBM heterogeneity and cell molecular characteristics. However, the same subtype of cells shared cell communication similarities.

miR‑425‑5p is associated with poor prognosis in patients with breast cancer and promotes cancer cell progression by targeting PTEN

Breast cancer (BC) is the most common invasive cancer in women, and it imposes a heavy burden on patients. microRNAs (miRNAs/miRs) have been found to play an important role in the development of tumors, but their role in the malignant progression of BC is unclear. In the present study, the expression level of miR‑425‑5p was examined in patients with BC, and its association with prognosis was investigated. In vitro experiments were performed to examine role of miR‑425‑5p in the development of BC cells. A downstream target gene of miR‑425‑5p was predicted using a miRNA target prediction tool and validated with a luciferase reporter assay. It was found that miR‑425‑5p expression was increased in BC tissues and cell lines, and was associated with tumor size, clinical stage, lymph node metastasis, distant metastasis and poor overall survival in patients with BC. Knockdown of miR‑425‑5p in BC cell lines inhibited proliferation and migration. PTEN was identified as a downstream target gene of miR‑425‑5p. Overexpression of PTEN was demonstrated to partially inhibit the promotional effect of miR‑425‑5p on cell proliferation and migration. Taken together, miR‑425‑5p is associated with poor prognosis, and promotes cell proliferation and migration via PTEN. Thus, miR‑425‑5p may serve as a therapeutic and prognostic marker for BC.

Perspectives on the expansion of human precision oncology and genomic approaches to sea turtle fibropapillomatosis

Our recent Communications Biology research article revealed the genomic drivers and therapeutic vulnerabilities of sea turtle fibropapillomatosis tumors. Fibropapillomatosis is a debilitating tumorous disease afflicting populations of green sea turtles globally. While a virus is involved in the development of this disease, it is increasingly understood that the key trigger is linked to anthropogenic disturbances of the environment. The specific environmental co-trigger(s) has yet to be functionally confirmed. Here we outline the next steps required to advance our understanding of this enigmatic disease, to enable us to more effectively clinically combat it and to ultimately tackle its environmental co-trigger to halt and hopefully reverse the spread of fibropapillomatosis.

Speed of Adoption of Immune Checkpoint Inhibitors of Programmed Cell Death 1 Protein and Comparison of Patient Ages in Clinical Practice vs Pivotal Clinical Trials

Importance

The US Food and Drug Administration (FDA) is increasing its pace of approvals for novel cancer therapeutics, including for immune checkpoint inhibitors of programmed cell death 1 protein (anti-PD-1 agents). However, little is known about how quickly anti-PD-1 agents agents reach eligible patients in practice or whether such patients differ from those studied in clinical trials that lead to FDA approval (pivotal clinical trials).

Objectives

To assess the speed with which anti-PD-1 agents agents reached eligible patients in practice and to compare the ages of patients treated in clinical practice with the ages of those treated in pivotal clinical trials.

Design, Setting, and Participants

This retrospective cohort study, performed from January 1, 2011, through August 31, 2016, included patients from the Flatiron Health Network who were eligible for anti-PD-1 agents treatment of selected cancer types, which included melanoma, non-small cell lung cancer (NSCLC), and renal cell carcinoma (RCC).

Main Outcomes and Measures

Cumulative proportions of eligible patients receiving anti-PD-1 agents treatment and their age distributions.

Results

The study identified 3089 patients who were eligible for anti-PD-1 agents treatment (median age, 66 [interquartile range, 56-75] years for patients with melanoma, 66 [interquartile range, 58-72] years for patients with RCC, and 67 [interquartile range, 59-74] years for patients with NSCLC; 1742 male [56.4%] and 1347 [43.6%] female; 2066 [66.9%] white). Of these patients, 2123 (68.7%) received anti-PD-1 agents treatment, including 439 eligible patients with melanoma (79.1%), 1417 eligible patients with NSCLC (65.6%), and 267 eligible patients with RCC (71.2%). Within 4 months after FDA approval, greater than 60% of eligible patients in each cohort had received anti-PD-1 agents treatment. Overall, similar proportions of older and younger patients received anti-PD-1 agents treatment during the first 9 months after FDA approval. However, there were significant differences in age between clinical trial participants and patients receiving anti-PD-1 agents treatment in clinical practice, with more patients being older than 65 years in clinical practice (range, 327 of 1365 [60.6%] to 46 of 72 [63.9%]) than in pivotal clinical trials (range, 38 of 120 [31.7%] to 223 of 544 [41.0%]; all P < .001).

Conclusions and Relevance

Anti-PD-1 agents rapidly reached patients in clinical practice, and patients treated in clinical practice differed significantly from patients treated in pivotal clinical trials. Future actions are needed to ensure that rapid adoption occurs on the basis of representative trial evidence.

Sea turtle fibropapilloma tumors share genomic drivers and therapeutic vulnerabilities with human cancers

Wildlife populations are under intense anthropogenic pressures, with the geographic range of many species shrinking, dramatic reductions in population numbers and undisturbed habitats, and biodiversity loss. It is postulated that we are in the midst of a sixth (Anthropocene) mass extinction event, the first to be induced by human activity. Further, threatening vulnerable species is the increased rate of emerging diseases, another consequence of anthropogenic activities. Innovative approaches are required to help maintain healthy populations until the chronic underlying causes of these issues can be addressed. Fibropapillomatosis in sea turtles is one such wildlife disease. Here, we applied precision-medicine-based approaches to profile fibropapillomatosis tumors to better understand their biology, identify novel therapeutics, and gain insights into viral and environmental triggers for fibropapillomatosis. We show that fibropapillomatosis tumors share genetic vulnerabilities with human cancer types, revealing that they are amenable to treatment with human anti-cancer therapeutics.

David Duffy et al. use a precision-medicine-based approach to study fibropapillomatosis tumors in sea turtles to identify environmental triggers and potential therapeutics. They show that these tumors share genetic similarities with human cancer types, and may be treatable using human anti-cancer therapies.

Global trends in nanomedicine research on triple negative breast cancer: a bibliometric analysis

Nanotechnology has emerged as a promising tool in the clinic to combat several difficult-to-manage diseases, such as cancer, which is the second leading cause of death worldwide. Chemotherapeutic drugs present several limitations such as undesired side effects, low specificity, resistance, and high relapse rates. Triple negative breast cancer (TNBC) is caused by cells that lack specific receptors in their membrane, such as estrogen (ER+) and progesterone (PR+) receptors, or by cells that do not express the amplification of human epidermal growth factor receptor-2 (HER-2+). This cancer type has poor prognosis, high relapse rates, and no targeted therapies. Thus, this study aimed to investigate the trends of nanotechnology research in TNBC and compare the contribution of research from different regions, institutions, and authors. A search of the studies published between 2012 and 2017, related to nanotechnology and TNBC, with different keyword combinations, was performed in the Scopus database. The keywords found in this search were grouped into four clusters, in which "breast cancer" was the most mentioned (1,133 times) and the word "MCF-7 cell line" is one of the latest hotspots that appeared in the year 2016. A total of 1,932 articles, which were cited 26,450 times, were identified. The USA accounted for 28.36% of the articles and 27.61% of the citations; however, none of its centers appeared in the list of 10 most productive ones in terms of publications. The journals Biomaterials and International Journal of Nanomedicine had the highest number of publications. The USA and China had the highest number of articles produced and cited; however, the highest average citation per article was from Singapore. The studies focused on the research of antineoplastic agents in animal models and cell culture, and these were the most used topics in research with nanotechnology and TNBC.

Superior efficacy of the antifungal agent ciclopirox olamine over gemcitabine in pancreatic cancer models

Ciclopirox olamine (CPX) is an antifungal agent that has recently demonstrated promising anti-neoplastic activity against hematologic and solid tumors. Here, we evaluated CPX compared with gemcitabine alone as well as their combination in human pancreatic cancer cell lines; BxPC-3, Panc-1, and MIA PaCa-2 and in humanized xenograft mouse models. We also examined the preclinical pharmacodynamic activity of CPX. CPX caused a pronounced decrease in cell proliferation and clonogenic growth potential. These inhibitory effects were accompanied by induction of reactive oxygen species (ROS), which were strongly associated with reduced Bcl-xL and survivin levels and activation of a panel of caspases, especially caspase-3, and finally resulted in apoptotic death. CPX-induced apoptosis was associated with reduced pEGFR (Y1068) and pAkt (Ser473) protein levels. Additionally, decreased proliferation was observed in CPX-treated xenografts tumors, demonstrating unique tumor regression and a profound survival benefit. Finally, we showed that CPX significantly abrogated gemcitabine-induced ROS levels in pancreatic tissues. These pre-clinical results have verified the superior antitumor efficacy of CPX over gemcitabine alone, while their combination is even more effective, providing the rationale for further clinical testing of CPX plus gemcitabine in pancreatic cancer patients.

The significance of intertumor and intratumor heterogeneity in liver cancer

Genomic analyses of primary liver cancer samples reveal a complex mutational landscape with vast intertumor and intratumor heterogeneity. Different primary liver tumors and subclones within each tumor display striking molecular and biological variations. Consequently, tumor molecular heterogeneity contributes to drug resistance and tumor relapse following therapy, which poses a substantial obstruction to improving outcomes of patients with liver cancer. There is an urgent need to the compositional and functional understanding of tumor heterogeneity. In this review, we summarize genomic and non-genomic diversities, which include stemness and microenvironmental causes of the functional heterogeneity of the primary liver cancer ecosystem. We discuss the importance and intricacy of intratumor heterogeneity in the context of cancer cell evolution. We also discuss methodologies applicable to determine intratumor heterogeneity and highlight the best-fit patient-derived in vivo and in vitro models to recapture the functional heterogeneity of primary liver cancer with the aim to improve future therapeutic strategies.

MicroRNAs as biomarkers for clinical studies

The development of better diagnostic and prognostic non-invasive biomarkers holds an enormous potential to improve the ability to diagnose and individualize treatment of a great number of human diseases and substantially reduce health care cost. The discovery of a fundamental role of microRNAs in the disease pathogenesis and their presence and stability in biological fluids has led to extensive investigation of the role of microRNAs as potential non-invasive biomarkers for disease diagnosis and prognosis. The result of this research has suggested that alterations of microRNAs may be sensitive indicators of various pathologies; however, despite the indisputable progress in this field, the diagnostic promise of microRNAs has remained a work in progress, and circulating microRNAs have not entered the field of clinical medicine yet. Commonly reported microRNAs as disease biomarkers are largely not disease-specific and the results are often contradicting in independent studies. This review summarizes the current knowledge on the role of microRNAs as disease indicators and emphasizes the current gaps, challenges, and questions that need to be addressed in future well-designed and well-controlled studies for a successful translation of microRNA profiling into clinically meaningful tests. Impact statement This review summarizes the current knowledge on the role of circulating miRNAs as clinical diagnostic biomarkers and highlights the challenges that need to be addressed in future studies for a successful translation of circulating miRNAs into a novel diagnostic tool.

Superoxide Dismutases in Pancreatic Cancer

The incidence of pancreatic cancer is increasing as the population ages but treatment advancements continue to lag far behind. The majority of pancreatic cancer patients have a K-ras oncogene mutation causing a shift in the redox state of the cell, favoring malignant proliferation. This mutation is believed to lead to nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation and superoxide overproduction, generating tumorigenic behavior. Superoxide dismutases (SODs) have been studied for their ability to manage the oxidative state of the cell by dismuting superoxide and inhibiting signals for pancreatic cancer growth. In particular, manganese superoxide dismutase has clearly shown importance in cell cycle regulation and has been found to be abnormally low in pancreatic cancer cells as well as the surrounding stromal tissue. Likewise, extracellular superoxide dismutase expression seems to favor suppression of pancreatic cancer growth. With an increased understanding of the redox behavior of pancreatic cancer and key regulators, new treatments are being developed with specific targets in mind. This review summarizes what is known about superoxide dismutases in pancreatic cancer and the most current treatment strategies to be advanced from this knowledge.