Roles of long noncoding RNA in triple-negative breast cancer.

INTRODUCTION: Long noncoding RNAs (lncRNAs) play crucial roles in regulating various hallmarks in cancers. Triple-negative (Estrogen receptor, ER; Human epidermal growth factor receptor 2, HER2; Progesterone receptor, PR) breast cancer (TNBC) is the most aggressive form of breast cancers with a poor prognosis and no available molecular targeted therapy. METHODS: We reviewed the current literature on the roles of lncRNAs in the pathogenesis, therapy resistance, and prognosis of patients with TBNC. RESULTS: LncRNAs are associated with TNBC pathogenesis, therapy resistance, and prognosis. For example, lncRNAs such as small nucleolar RNA host gene 12 (SNHG12), highly upregulated in liver cancer (HULC) HOX transcript antisense intergenic RNA (HOTAIR), lincRNA-regulator of reprogramming (LincRNA-ROR), etc., are aberrantly expressed in TNBC and are involved in the pathogenesis of the disease. LncRNAs act as a decoy, scaffold, or sponge to regulate the expression of genes, miRNAs, and transcription factors associated with pathogenesis and progression of TNBC. Moreover, lncRNAs such as ferritin heavy chain 1 pseudogene 3 (FTH1P3), BMP/OP-responsive gene (BORG) contributes to the therapy resistance property of TNBC through activating ABCB1 (ATP-binding cassette subfamily B member 1) drug efflux pumps by increasing DNA repair capacity or by inducing signaling pathway involved in therapeutic resistance. CONCLUSION: In this review, we outline the functions of various lncRNAs along with their molecular mechanisms involved in the pathogenesis, therapeutic resistance of TBNC. Also, the prognostic implications of lncRNAs in patients with TNBC is illustrated. Moreover, potential strategies targeting lncRNAs against highly aggressive TNBC is discussed in this review.

Implications of estrogen and its receptors in colorectal carcinoma.

Estrogens have been implicated in the pathogenesis of various cancer types, including colorectal carcinoma (CRC). Estrogen receptors such as ERα and ERß activate intracellular signaling cascades followed by binding to estrogen, resulting in important changes in cellular behaviors. The nuclear estrogen receptors, i.e. ERß and ERα are responsible for the genomic actions of estrogens, whereas the other receptor, such as G protein-coupled estrogen receptor (GPER) regulates rapid non-genomic actions, which lead to secondary gene expression changes in cells. ERß, the predominant estrogen receptor expressed in both normal and non-malignant colonic epithelium, has protective roles in colon carcinogenesis. ERß may exert the anti-tumor effect through selective activation of pro-apoptotic signaling, increasing DNA repair, inhibiting expression of oncogenes, regulating cell cycle progression, and also by changing the micro-RNA pool and DNA-methylation. Thus, a better understanding of the underlying mechanisms of estrogen and its receptors in CRC pathogenesis could provide a new horizon for effective therapeutic development. Furthermore, using synthetic or natural compounds as ER agonists may induce estrogen-mediated anti-cancer activities against colon cancer. In this study, we report the most recent pre-clinical and experimental evidences related to ERs in CRC development. Also, we reviewed the actions of naturally occurring and synthetic compounds, which have a protective role against CRC development by acting as ER agonist.

Identification of novel mutations and functional impacts of EPAS1 in colorectal cancer.

Endothelial PAS domain-containing protein 1 (EPAS1) has implications in many cancers. However, the molecular behaviours, functional roles and mutational status of EPAS1 have never been studied in colorectal carcinoma (CRC). The study aims to examine the genetic alterations and functional roles of EPAS1 in CRC. In addition, the clinical impacts of EPAS1 in CRC were studied. Significant EPAS1 DNA amplification (63.4%; n = 52/82) and consequent mRNA overexpression (72%; n = 59/82) were noted in patients with CRC. In CRC, 16% (n = 13/82) of the patients had mutations in the EPAS1 coding sequence and most of the mutated samples exhibited aberrant DNA changes and mRNA overexpression. We have identified two novel variants, c.1084C>T; p.L362L and c.1121T>G; p.F374C in CRC. These EPAS1 aberrations in CRC were correlated with clinicopathological parameters, including tumour size, histological grade, T-stages, cancer perforation as well as the presence of synchronous cancer. Also, reduced cell proliferation, wound healing, migration and invasion were noted in colon cancer cells followed by EPAS1 silencing. To conclude, the results obtained from the current study indicated that EPAS1 plays important role in colorectal carcinogenesis, thus, could be useful as a prognostic marker and as a target for therapy development.

VEGF-A/VEGF-B/VEGF-C expressions in non-hereditary, non-metastatic phaeochromocytoma.

Vascular endothelial growth factor (VEGF) is important in pathogenesis of different cancers. The aim of this study is to investigate the relationships between different VEGFs and clinicopathological factors in patients with phaeochromocytomas. Twenty patients (10 men; 10 women) with non-hereditary, non-metastatic phaeochromocytomas were examined for VEGF mRNA expressions by polymerase chain reaction. The expressions were correlated with the clinical and pathological factors of the patients. In addition, mouse double minute 2 (MDM2) expression in these tumours were studied by immunohistochemistry. High expressions of VEGF-A, VEGF-B, and VEGF-C mRNA were detected in 11 (55%), 9 (45%), and 9 (45%) of the tumours respectively. High expression of VEGF-A in phaeochromocytomas was significantly correlated with the tumour size (p=0.025) but did not correlate with patients' age, gender, and tumour laterality. Besides, there was a trend of VEGF-A expression correlated with MDM2 expression (p=0.064). On the other hand, expressions of VEGF-B and VEGF-C were not significantly correlated with tumour size, patients' age, gender, tumour laterality, and MDM2 expression. In addition, high expressions of VEGF-B and VEGF-A were associated with increase of tumour size (p=0.042). Co-expression of different VEGFs did not correlate with MDM2 expression. To conclude, there is a role for VEGF-A/VEGF-B/VEGF-C in the pathogenesis of non-hereditary, non-metastatic phaeochromocytomas.

Identification of Novel Mutations and Expressions of EPAS1 in Phaeochromocytomas and Paragangliomas.

Endothelial PAS domain-containing protein 1 (EPAS1) is an oxygen-sensitive component of the hypoxia-inducible factors (HIFs) having reported implications in many cancers by inducing a pseudo-hypoxic microenvironment. However, the molecular dysregulation and clinical significance of EPAS1 has never been investigated in depth in phaeochromocytomas/paragangliomas. This study aims to identify EPAS1 mutations and alterations in DNA copy number, mRNA and protein expression in patients with phaeochromocytomas/paragangliomas. The association of molecular dysregulations of EPAS1 with clinicopathological factors in phaeochromocytomas and paragangliomas were also analysed. High-resolution melt-curve analysis followed by Sanger sequencing was used to detect mutations in EPAS1. EPAS1 DNA number changes and mRNA expressions were examined by polymerase chain reaction (PCR). Immunofluorescence assay was used to study EPAS1 protein expression. In phaeochromocytomas, 12% (n = 7/57) of patients had mutations in the EPAS1 sequence, which includes two novel mutations (c.1091A > T; p.Lys364Met and c.1129A > T; p.Ser377Cys). Contrastingly, in paragangliomas, 7% (n = 1/14) of patients had EPAS1 mutations and only the c.1091A > T; p.Lys364Met mutation was detected. In silico analysis revealed that the p.Lys364Met mutation has pathological potential based on the functionality of the protein, whereas the p.Ser377Cys mutation was predicted to be neutral or tolerated. The majority of the patients had EPAS1 DNA amplification (79%; n = 56/71) and 53% (n = 24/45) patients shown mRNA overexpression. Most of the patients with EPAS1 mutations exhibited aberrant DNA changes, mRNA and protein overexpression. In addition, these alterations of EPAS1 were associated with tumour weight and location. Thus, the molecular dysregulation of EPAS1 could play crucial roles in the pathogenesis of phaeochromocytomas and paragangliomas.

Molecular Deregulation of EPAS1 in the Pathogenesis of Esophageal Squamous Cell Carcinoma.

Endothelial PAS domain-containing protein 1 (EPAS1) is an angiogenic factor and its implications have been reported in many cancers but not in esophageal squamous cell carcinoma (ESCC). Herein, we aim to examine the genetic and molecular alterations, clinical implications, and functional roles of EPAS1 in ESCC. High-resolution melt-curve analysis and Sanger sequencing were used to detect mutations in EPAS1 sequence. EPAS1 DNA number changes and mRNA expressions were analyzed by polymerase chain reaction. in vitro functional assays were used to study the impact of EPAS1 on cellular behaviors. Overall, 7.5% (n = 6/80) of patients with ESCC had mutations in EPAS1, and eight novel variants (c.1084C>T, c.1099C>A, c.1145_1145delT, c.1093C>G, c.1121T>G, c.1137_1137delG, c.1135_1136insT, and c.1091_1092insT) were detected. Among these mutations, four were frameshift (V382Gfs*12, A381Lfs*13, K379Ifs*6, and K364Nfs*12) mutations and showed the potential of non-sense-mediated mRNA decay (NMD) in computational analysis. The majority of patients showed molecular deregulation of EPAS1 [45% (n = 36/80) DNA amplification, 42.5% (n = 34/80) DNA deletion, as well as 53.7% (n = 43/80) high mRNA expression, 20% (n = 16/80) low mRNA expression]. These alterations of EPAS1 were associated with tumor location and T stages. Patients with stage III ESCC having EPAS1 DNA amplification had poorer survival rates in comparison to EPAS1 DNA deletion (p = 0.04). In addition, suppression of EPAS1 in ESCC cells showed reduced proliferation, wound healing, migration, and invasion in comparison to that of control cells. Thus, the molecular and functional studies implied that EPAS1 plays crucial roles in the pathogenesis of ESCC and has the potential to be used as a prognostic marker and as a therapeutic target.

Genome Sequencing in Esophageal Squamous Cell Carcinoma.

Technological advances in the form of next-generation sequencing allow sequencing of large numbers of different DNA sequences in a single/parallel reaction compared to conventional sequencing. It is a powerful tool which has enabled comprehensive characterization of esophageal squamous cell carcinoma. Whole-genome sequencing is the most comprehensive but expensive, whereas whole-exome sequencing is cost-effective, but it only works for the known genes. Thus, second-generation sequencing methods can provide a complete picture of the esophageal squamous cell carcinoma genome by detecting and discovering different type of alterations in the cancer which may lead to the development of effective diagnostic and therapeutic approaches for esophageal squamous cell carcinoma.

Plasticity of Cancer Stem Cell: Origin and Role in Disease Progression and Therapy Resistance.

In embryonic development and throughout life, there are some cells can exhibit phenotypic plasticity. Phenotypic plasticity is the ability of cells to differentiate into multiple lineages. In normal development, plasticity is highly regulated whereas cancer cells re-activate this dynamic ability for their own progression. The re-activation of these mechanisms enables cancer cells to acquire a cancer stem cell (CSC) phenotype- a subpopulation of cells with increased ability to survive in a hostile environment and resist therapeutic insults. There are several contributors fuel CSC plasticity in different stages of disease progression such as a complex network of tumour stroma, epidermal microenvironment and different sub-compartments within tumour. These factors play a key role in the transformation of tumour cells from a stable condition to a progressive state. In addition, flexibility in the metabolic state of CSCs helps in disease progression. Moreover, epigenetic changes such as chromatin, DNA methylation could stimulate the phenotypic change of CSCs. Development of resistance to therapy due to highly plastic behaviour of CSCs is a major cause of treatment failure in cancers. However, recent studies explored that plasticity can also expose the weaknesses in CSCs, thereby could be utilized for future therapeutic development. Therefore, in this review, we discuss how cancer cells acquire the plasticity, especially the role of the normal developmental process, tumour microenvironment, and epigenetic changes in the development of plasticity. We further highlight the therapeutic resistance property of CSCs attributed by plasticity. Also, outline some potential therapeutic options against plasticity of CSCs. Graphical Abstract .

MicroRNAs, a Promising Target for Breast Cancer Stem Cells.

Reactivation of the stem cell programme in breast cancer is significantly associated with persistent cancer progression and therapeutic failure. Breast cancer stem cells (BCSCs) are involved in the process of breast cancer initiation, metastasis and cancer relapse. Among the various important cues found in the formation and progression of BCSCs, microRNAs (miRNAs or miRs) play a pivotal role by regulating the expression of various tumour suppressor genes or oncogenes. Accordingly, there is evidence that miRNAs are associated with BCSC self-renewal, differentiation, invasion, metastasis and therapy resistance, and therefore cancer recurrence. miRNAs execute their roles by regulating the expression of stemness markers, activation of signalling pathways or their components and regulation of transcription networks in BCSCs. Therefore, a better understanding of the association between BCSCs and miRNAs has the potential to help design more effective and safer therapeutic solutions against breast cancer. Thus, an miRNA-based therapeutic strategy may open up new horizons for the treatment of breast cancer in the future. In view of this, we present the progress to date of miRNA research associated with stemness marker expression, signalling pathways and activation of transcription networks to regulate the self-renewal, differentiation and therapy resistance properties of BCSCs.

Novel Therapeutics Against Breast Cancer Stem Cells by Targeting Surface Markers and Signaling Pathways.

BACKGROUND: Breast cancer remains to be one of the deadliest forms of cancers, owing to the drug resistance and tumor relapse caused by breast cancer stem cells (BCSCs) despite notable advancements in radio-chemotherapies. OBJECTIVES: To find out novel therapeutics against breast cancer stem cells by aiming surface markers and signaling pathways. METHODS: A systematic literature search was conducted through various electronic databases including, Pubmed, Scopus, Google scholar using the keywords "BCSCs, surface markers, signaling pathways and therapeutic options against breast cancer stem cell. Articles selected for the purpose of this review were reviewed and extensively analyzed. RESULTS: Novel therapeutic strategies include targeting BCSCs surface markers and aberrantly activated signaling pathways or targeting their components, which play critical roles in self-renewal and defense, have been shown to be significantly effective against breast cancer. In this review, we represent a number of ways against BCSCs surface markers and hyper-activated signaling pathways to target this highly malicious entity of breast cancer more effectively in order to make a feasible and useful strategy for successful breast cancer treatment. In addition, we discuss some characteristics of BCSCs in disease progression and therapy resistance. CONCLUSION: BCSCs involved in cancer pathogenesis, therapy resistance and cancer recurrence. Thus, it is suggested that a multi-dimensional therapeutic approach by targeting surface markers and aberrantly activated signaling pathways of BCSCs alone or in combination with each other could really be worthwhile in the treatment of breast cancer.

Natural Compounds Targeting Cancer Stem Cells: A Promising Resource for Chemotherapy.

BACKGROUND: Cancer Stem Cells (CSCs) are the subpopulation of cancer cells which are directly involved in drug resistance, metastases to distant organ and cancer recurrence. METHODS: A systematic literature search was conducted through various electronic databases including, Pubmed, Scopus, Google scholar using the keywords "cancer stem cells" and "natural compounds" in the present study. Articles published between 1999 and 2019 were reviewed. All the expositions concerning CSCs associated cancer pathogenesis and therapy resistance, as well as targeting these properties of CSCs by natural compounds were selected for the current study. RESULTS: Natural compounds have always been thought as a rich source of biologically active principles, which target aberrantly activated signaling pathways and other modalities of CSCs, while tethering painful side effects commonly involved in the first-line and second-line chemo-radiotherapies. In this review, we have described the key signaling pathways activated in CSCs to maintain their survival and highlighted how natural compounds interrupt these signaling pathways to minimize therapy resistance, pathogenesis and cancer recurrence properties of CSCs, thereby providing useful strategies to treat cancer or aid in cancer therapy improvement. Like normal stem cells, CSCs rely on different signaling pathways and other properties for their maintenance. Therefore, the success of cancer treatment depends on the development of proper anti-neoplastic drugs capable of intercepting those signaling pathways as well as other properties of CSCs in order to eradicate this evasive subpopulation of cancer cells. CONCLUSION: Compounds of natural origin might act as an outstanding source to design novel therapies against cancer stem cells.

Hereditary breast cancer; Genetic penetrance and current status with BRCA.

The most important cause of developing hereditary breast cancer is germline mutations occurring in breast cancer (BCs) susceptibility genes, for example, BRCA1, BRCA2, TP53, CHEK2, PTEN, ATM, and PPM1D. Many BC susceptibility genes can be grouped into two classes, high- and low-penetrance genes, each of which interact with multiple genes and environmental factors. However, the penetrance of genes can also be represented by a spectrum, which ranges between high and low. Two of the most common susceptibility genes are BRCA1 and BRCA2, which perform vital cellular functions for repair of homologous DNA. Loss of heterozygosity accompanied by hereditary mutations in BRCA1 or BRCA2 increases chromosomal instability and the likelihood of cancer, as well as playing a key role in stimulating malignant transformation. With regard to pathological features, familial breast cancers caused by BRCA1 mutations usually differ from those caused by BRCA2 mutations and nonfamilial BCs. It is essential to acquire an understanding of these pathological features along with the genetic history of the patient to offer an individualized treatment. Germline mutations in BRCA1 and BRCA2 genes are the main genetic and inherited factors for breast and ovarian cancer. In fact, these mutations are very important in developing early onset and increasing the risk of familial breast and ovarian cancer and responsible for 90% of hereditary BC cases. Therefore, according to the conducted studies, screening of BRCA1 and BRCA2 genes is recommended as an important marker for early detection of all patients with breast or ovarian cancer risk with family history of the disease. In this review, we summarize the role of hereditary genes, mainly BRCA1 and BRCA2, in BC.

Tumour suppressor properties of miR-15a and its regulatory effects on BCL2 and SOX2 proteins in colorectal carcinomas.

OBJECTIVES: In this study, we aimed to investigate the expression pattern, clinicopathological significance and tumour suppressive properties of miR-15a in patients with colorectal carcinomas. METHODS: Tissue samples from 87 patients with primary colorectal carcinomas, 50 matched metastatic lymph node and 37 non-neoplastic colon (control) were prospectively recruited. The expression level of miR-15a was measured by quantitative real-time polymerase chain reaction. Restoration/overexpression of the miR-15a was achieved by exogenous transfection. Four colon cancer cell lines (SW480, CaCO2, SW48 and HCT116) and a non-cancer colon cell line (FHC) were also used for examining the miR-15a induced tumour suppression properties using various in-vitro and immunological assays. RESULTS: Downregulation of miR-15a was noted in ~ 62% of the colorectal carcinoma tissues and it was positively correlated with the presence of cancer recurrence in patients with colorectal carcinomas (p = 0.05). Also, these patients with low miR-15a expression showed relatively shorter survival time when compared to those with miR-15a overexpression. Following miR-15a exogenous overexpression, colon cancer cells showed reduced cell proliferation, low colony formation, less cell invasion properties and mitochondrial respiration when compared to control cells. In addition, BCL2 and SOX2 proteins showed a significant downregulation following miR-15a overexpression suggesting its regulatory role in cancer growth, apoptosis and stemness. CONCLUSION: This study has confirmed the tumour suppressor properties of miR-15a in colorectal cancers. Therefore, its modulation has potential implications in controlling various biological and pathogenic processes in colon carcinogenesis via targeting its downstream proteins such as BCL2 and SOX2.

Evaluation of multidisciplinary strategies and traditional approaches in teaching pathology in medical students.

This study aims to evaluate the impact on the implementation of multiple strategies to improve medical student's pathology learning experience. In two consecutive years, medical students after a whole year of enrolling in pathology teaching, were invited to complete questionnaires rating and commenting on the personal learning experience of multiple teaching resources delivered in pathology. In both years, the overall score was high (mean score = 4.57 ± 0.63 /5) for the newly introduced sessions, namely histology lectures, clinical integrations and virtual microscopy pre-practical sessions. However, this was only marginally different from that of traditional practical (mean = 4.37 ± 0.68/5) and pathology lecture sessions (mean = 4.42 ± 0.61 /5). In addition, 53% positive correlation was noted for the overall responses between virtual microscopy guided pathology modules and practical sessions indicating the benefit of virtual microscopy in better preparing students for these sessions (P < 0.001). Qualitative comments suggested that the virtual microscopy sessions along with clinical scenario based learning were extremely useful for students' learning in pathology. To conclude, a multidisciplinary approach by clinical integration and flexibility in the mode of delivery by the use of virtual microscopy has the potential to better engage students to the learning of pathology.

DNA Genome Sequencing in Esophageal Adenocarcinoma.

Next-generation sequencing refers to the high-throughput DNA sequencing technologies, which are capable of sequencing large numbers of different DNA sequences in a single/parallel reaction. It is a powerful tool to identify inherited and acquired genetic alterations associated with the development of esophageal adenocarcinoma. Whole-genome sequencing is the most comprehensive but expensive, whereas whole-exome sequencing is cost-effective but it only works for the known genes. Thus, second-generation sequencing methods can provide a complete picture of the esophageal adenocarcinoma genome by detecting and discovering different type of alterations in the cancer. This would help in diagnostics and will further help in developing personalized medicine in esophageal adenocarcinoma.

Promoter hypermethylation inactivate tumor suppressor FAM134B and is associated with poor prognosis in colorectal cancer.

The present study aims to examine promoter methylation status of FAM134B in a large cohort of patients with colorectal adenocarcinomas. The clinical significances and correlations of FAM134B promoter methylation with its expression are also analysed. Methylation-specific high-resolution melt-curve analysis followed by sequencing was used to identify FAM134B promoter methylation in colorectal adenomas (N = 32), colorectal adenocarcinomas (N = 164), matched adjacent non-neoplastic colorectal mucosae (N = 83) and colon cancer cell lines (N = 4). FAM134B expression was studied by real-time quantitative polymerase chain reaction, immunohistochemistry, and Western blots. FAM134B promoter methylation was more frequent in adenocarcinomas (52%; 85/164) when compared to that of adenomas (28%; 9/32) and non-neoplastic mucosae (35%; 29/83). Cancer cells exhibited higher methylation when compared to non-neoplastic cells. FAM134B promoter methylation was inversely correlated with low FAM134B copy number and mRNA/protein expressions, whereas in-vitro demethylation has restored FAM134B expression in colon cancer cells. FAM134B promoter methylation was associated with high histological grade (P = .025), presence of peri-neural infiltration (P = .012), lymphovascular invasion (P = .021), lymph node metastasis (P = .0001), distant metastasis (P = .0001) and advanced pathological stages (P = .0001). In addition, FAM134B promoter methylation correlated with cancer recurrence and poor survival rates of patients with colorectal adenocarcinomas. To conclude, FAM134B promoter methylation plays a key role in regulating FAM134B expression in vitro and in vivo, which in turn contributes to the prediction of the biological aggressiveness of colorectal adenocarcinomas. Furthermore, FAM134B methylation might act as a marker in predicting clinical prognosis in patients with colorectal adenocarcinomas.

Review of sequencing platforms and their applications in phaeochromocytoma and paragangliomas.

Genetic testing is recommended for patients with phaeochromocytoma (PCC) and paraganglioma (PGL) because of their genetic heterogeneity and heritability. Due to the large number of susceptibility genes associated with PCC/PGL, next-generation sequencing (NGS) technology is ideally suited for carrying out genetic screening of these individuals. New generations of DNA sequencing technologies facilitate the development of comprehensive genetic testing in PCC/PGL at a lower cost. Whole-exome sequencing and targeted NGS are the preferred methods for screening of PCC/PGL, both having precise mutation detection methods and low costs. RNA sequencing and DNA methylation studies using NGS technology in PCC/PGL can be adopted to act as diagnostic or prognostic biomarkers as well as in planning targeted epigenetic treatment of patients with PCC/PGL. The designs of NGS having a high depth of coverage and robust analytical pipelines can lead to the successful detection of a wide range of genomic defects in PCC/PGL. Nevertheless, the major challenges of this technology must be addressed before it has practical applications in the clinical diagnostics to fulfill the goal of personalized medicine in PCC/PGL. In future, novel approaches of sequencing, such as third and fourth generation sequencing can alter the workflow, cost, analysis, and interpretation of genomics associated with PCC/PGL.

MicroRNA 183 family profiles in pheochromocytomas are related to clinical parameters and SDHB expression.

This study aims to examine the expression profiles of the miR-183 cluster (miR-96/182/183) in pheochromocytoma. Pheochromocytoma tissues were prospectively collected from 50 patients with pheochromocytoma. Expression of miR-183 cluster members and SDHB protein expression were analyzed in these tissues by quantitative real-time polymerase chain reaction and immunohistochemistry, respectively. The expression of miR-183 cluster members in pheochromocytomas was correlated with the clinical and pathological parameters of these patients. The expression levels of miR-183 cluster members were predominantly downregulated or deleted in pheochromocytoma. Low expression or deletion of miR-96 was predominantly noted in younger patients with pheochromocytoma (<50 years, P=.01). Female patients in the study group showed marked deletion of miR-182 (P=.05). Deletion of the cluster was also associated with SDHB protein expression in pheochromocytoma. Moreover, patients with low miR-183 cluster expression had a slightly better survival rate when compared with patients with high expression. To conclude, the findings indicate a role for miR-183 cluster members in the pathogenesis and clinical progression of pheochromocytoma.

Silent genetic alterations identified by targeted next-generation sequencing in pheochromocytoma/paraganglioma: A clinicopathological correlations.

AIMS: The goal of this pilot study was to develop a customized, cost-effective amplicon panel (Ampliseq) for target sequencing in a cohort of patients with sporadic phaeochromocytoma/paraganglioma. METHODS: Phaeochromocytoma/paragangliomas from 25 patients were analysed by targeted next-generation sequencing approach using an Ion Torrent PGM instrument. Primers for 15 target genes (NF1, RET, VHL, SDHA, SDHB, SDHC, SDHD, SDHAF2, TMEM127, MAX, MEN1, KIF1Bß, EPAS1, CDKN2 & PHD2) were designed using ion ampliseq designer. Ion Reporter software and Ingenuity® Variant Analysis™ software (www.ingenuity.com/variants) from Ingenuity Systems were used to analysis these results. RESULTS: Overall, 713 variants were identified. The variants identified from the Ion Reporter ranged from 64 to 161 per patient. Single nucleotide variants (SNV) were the most common. Further annotation with the help of Ingenuity variant analysis revealed 29 of these 713variants were deletions. Of these, six variants were non-pathogenic and four were likely to be pathogenic. The remaining 19 variants were of uncertain significance. The most frequently altered gene in the cohort was KIF1B followed by NF1. Novel KIF1B pathogenic variant c.3375+1G>A was identified. The mutation was noted in a patient with clinically confirmed neurofibromatosis. Chromosome 1 showed the presence of maximum number of variants. CONCLUSIONS: Use of targeted next-generation sequencing is a sensitive method for the detecting genetic changes in patients with phaeochromocytoma/paraganglioma. The precise detection of these genetic changes helps in understanding the pathogenesis of these tumours.