Biomarker testing for advanced lung cancer by next-generation sequencing; a valid method to achieve a comprehensive glimpse at mutational landscape

Background: Next-generation sequencing (NGS) based assay for finding an actionable driver in non-small-cell lung cancer is a less used modality in clinical practice. With a long list of actionable targets, limited tissue, arduous single-gene assays, the alternative of NGS for broad testing in one experiment looks attractive. We report here our experience with NGS for biomarker testing in hundred advanced lung cancer patients. Methods: Predictive biomarker testing was performed using the Ion AmpliSeq™ Cancer Hotspot Panel V2 (30 tumors) and Oncomine™ Solid Tumor DNA and Oncomine™ Solid Tumor Fusion Transcript kit (70 tumors) on IonTorrent sequencing platform. Results: One-seventeen distinct aberrations were detected across 29 genes in eighty-six tumors. The most commonly mutated genes were TP53 (43% cases), EGFR (23% cases) and KRAS (17% cases). Thirty-four patients presented an actionable genetic variant for which targeted therapy is presently available, and fifty-two cases harbored non-actionable variants with the possibility of recruitment in clinical trials. NGS results were validated by individual tests for detecting EGFR mutation, ALK1 rearrangement, ROS1 fusion, and c-MET amplification. Compared to single test, NGS exhibited good agreement for detecting EGFR mutations and ALK1 fusion (sensitivity- 88.89%, specificity- 100%, Kappa-score 0.92 and sensitivity- 80%, specificity- 100%, Kappa-score 0.88; respectively). Further, the response of patients harboring tyrosine kinase inhibitor (TKI) sensitizing EGFR mutations was assessed. The progression-free-survival of EGFR positive patients on TKI therapy, harboring a concomitant mutation in PIK3CAmTOR and/or RAS-RAF-MAPK pathway gene and/or TP53 gene was inferior to those with sole-sensitizing EGFR mutation (2 months vs. 9.5 months, P = 0.015). Conclusions: This is the first study from South Asia looking into the analytical validity of NGS and describing the mutational landscape of lung cancer patients to study the impact of co-mutations on cancer biology and treatment outcome. Our study demonstrates the clinical utility of NGS testing for identifying actionable variants and making treatment decisions in advanced lung cancer

Triiodothyronine (T3) upregulates the expression of proto-oncogene TGFA independent of MAPK/ERK pathway activation in the human breast adenocarcinoma cell line, MCF7

ABSTRACT Objective: To verify the physiological action of triiodothyronine T3 on the expression of transforming growth factor α (TGFA) mRNA in MCF7 cells by inhibition of RNA Polymerase II and the MAPK/ERK pathway Materials and methods: The cell line was treated with T3 at a physiological dose (10−9M) for 10 minutes, 1 and 4 hour (h) in the presence or absence of the inhibitors, α-amanitin (RNA polymerase II inhibitor) and PD98059 (MAPK/ERK pathway inhibitor). TGFA mRNA expression was analyzed by RT-PCR. For data analysis, we used ANOVA, complemented with the Tukey test and Student t-test, with a minimum significance of 5%. Results: T3 increases the expression of TGFA mRNA in MCF7 cells in 4 h of treatment. Inhibition of RNA polymerase II modulates the effect of T3 treatment on the expression of TGFA in MCF7 cells. Activation of the MAPK/ERK pathway is not required for T3 to affect the expression of TGFA mRNA. Conclusion: Treatment with a physiological concentration of T3 after RNA polymerase II inhibition altered the expression of TGFA. Inhibition of the MAPK/ERK pathway after T3 treatment does not interfere with the TGFA gene expression in a breast adenocarcinoma cell line.

Mouse Models as a Tool for Understanding Progression in Braf(V600E)-Driven Thyroid Cancers

The development of next generation sequencing (NGS) has led to marked advancement of our understanding of genetic events mediating the initiation and progression of thyroid cancers. The NGS studies have confirmed the previously reported high frequency of mutually-exclusive oncogenic alterations affecting BRAF and RAS proto-oncogenes in all stages of thyroid cancer. Initially identified by traditional sequencing approaches, the NGS studies also confirmed the acquisition of alterations that inactivate tumor protein p53 (TP53) and activate phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) in advanced thyroid cancers. Novel alterations, such as those in telomerase reverse transcriptase (TERT) promoter and mating-type switching/sucrose non-fermenting (SWI/SNF) complex, are also likely to promote progression of the BRAF(V600E)-driven thyroid cancers. A number of genetically engineered mouse models (GEMM) of BRAF(V600E)-driven thyroid cancer have been developed to investigate thyroid tumorigenesis mediated by oncogenic BRAF and to explore the role of genetic alterations identified in the genomic analyses of advanced thyroid cancer to promote tumor progression. This review will discuss the various GEMMs that have been developed to investigate oncogenic BRAF(V600E)-driven thyroid cancers.

Cutaneous Angiosarcoma of the Foot Accompanied by Multiple Myeloma: The First Case Report / 대한피부과학회지

Although the exact etiology of cutaneous angiosarcoma remains unclear, MYC gene amplification has been recently discovered as a new pathogenesis. MYC is a proto-oncogene, and aberration of MYC signaling in malignancies is associated with tumor metastasis, recurrence, and mortality. Moreover, upregulation of the miRNA polycistron, miR-17-92 cluster, were confirmed in both cutaneous angiosarcoma and multiple myeloma with MYC amplification. The correlation between MYC and miRNA expression is predictable as the coincident aberrant phenotype in two diseases. Moreover, the exploiting MYC dependency may be an attractive disease-specific strategy for the diagnosis and treatment of patients who are unaware of the causes of cutaneous angiosarcoma. Herein, a rare case of cutaneous angiosarcoma of the foot, which is also the first case of cutaneous angiosarcoma accompanied by multiple myeloma, has been described.

Prominent Inflammatory Features of Monocytes/Macrophages in Acute Calcium Pyrophosphate Crystal Arthritis: a Comparison with Acute Gouty Arthritis

Calcium pyrophosphate (CPP) crystals can present as acute inflammatory arthritis which is known as an acute CPP crystal arthritis. Although monocytes/macrophages have been shown to play a role in the initiation of crystal-mediated inflammatory responses, differences in their phenotypes between acute CPP crystal arthritis and acute gouty arthritis have not yet been investigated. We examined the immunological characteristics of synovial monocytes/macrophages in patients with acute CPP crystal and acute gouty arthritis. CD14⁺CD3⁻CD19⁻CD56⁻ cell frequencies in synovial fluid mononuclear cells (SFMCs) were measured. Expression of pro- and anti-inflammatory cytokines and markers was determined. The SFMCs were dominated by a population of monocytes/macrophages in acute CPP crystal arthritis similar to that in acute gout. Synovial monocytes/macrophages showed the phenotypes of infiltrated monocytes as shown by expression of CD88, C-C chemokine receptor type 2, myeloid-related protein (MRP)8 and MRP14 but not proto-oncogene tyrosine-protein kinase MER. Comparatively, the CD14⁺ cells from patients with acute CPP crystal arthritis had similar high levels of IL-1β and TNF-α production but significantly lower expression of IL-10 and M2 marker (CD163). The monocytes/macrophages had the capacity to produce IL-8 in response to CPP crystals. Proinflammatory features were more dominant in monocytes/macrophages during acute CPP crystal arthritis than those during acute gouty arthritis.

Genetic and epigenetic of medullary thyroid cancer

Medullary thyroid carcinoma [MTC] is an infrequent calcitonin-producing neuroendocrine tumor that initiates from the parafollicular C cells of the thyroid gland. Several genetic and epigenetic alterations are collaterally responsible for medullary thyroid carcinogenesis. In this review article, we shed light on all the genetic and epigenetic hallmarks of MTC. From the genetic perspective, RET, HRAS, and KRAS are the most important genes that are characterized in MTC. From the epigenetic perspective, Ras-association domain family member 1A, telomerase reverse transcriptase promoter methylations, overexpression of histone methyltransferases, EZH2 and SMYD3, and wide ranging increase and decrease in non-coding RNAs can be responsible for medullary thyroid carcinogenesis

Convergence of Cancer Metabolism and Immunity: an Overview

Cancer metabolism as a field of research was founded almost 100 years ago by Otto Warburg, who described the propensity for cancers to convert glucose to lactate despite the presence of oxygen, which in yeast diminishes glycolytic metabolism known as the Pasteur effect. In the past 20 years, the resurgence of interest in cancer metabolism provided significant insights into processes involved in maintenance metabolism of non-proliferating cells and proliferative metabolism, which is regulated by proto-oncogenes and tumor suppressors in normal proliferating cells. In cancer cells, depending on the driving oncogenic event, metabolism is re-wired for nutrient import, redox homeostasis, protein quality control, and biosynthesis to support cell growth and division. In general, resting cells rely on oxidative metabolism, while proliferating cells rewire metabolism toward glycolysis, which favors many biosynthetic pathways for proliferation. Oncogenes such as MYC, BRAF, KRAS, and PI3K have been documented to rewire metabolism in favor of proliferation. These cell intrinsic mechanisms, however, are insufficient to drive tumorigenesis because immune surveillance continuously seeks to destroy neo-antigenic tumor cells. In this regard, evasion of cancer cells from immunity involves checkpoints that blunt cytotoxic T cells, which are also attenuated by the metabolic tumor microenvironment, which is rich in immuno-modulating metabolites such as lactate, 2-hydroxyglutarate, kynurenine, and the proton (low pH). As such, a full understanding of tumor metabolism requires an appreciation of the convergence of cancer cell intrinsic metabolism and that of the tumor microenvironment including stromal and immune cells.

Pheochromocytoma Developed in a Boy with Multiple Endocrine Neoplasia Type 2A Confirmed by the RET Proto-Oncogene Mutation / 임상소아혈액종양

A 9-year-old boy presented with increased sweating and abdominal pain. His mother and uncle had been diagnosed with bilateral pheochromocytoma and medullary thyroid carcinoma. Magnetic resonance imaging of the boy's abdomen revealed a 7.5 cm×7.0 cm×6.0 cm mass with a thick peripheral enhancing wall and fluid-fluid level at the right suprarenal region. His ¹²³I-meta-iodobenzylguanidine (MIBG) scan showed a large mass with increased MIBG uptake in the right adrenal gland. The levels of serum norepinephrine, urine epinephrine/norepinephrine, metanephrine, and vanillylmandelic acid were elevated. He, his mother, and two sisters tested positive for the known mutation of multiple endocrine neoplasia type 2A, Cys634Tyr in RET proto-oncogene. Laparoscopic tumor excision and right adrenalectomy were performed. Final diagnosis was pheochromocytoma with malignant behavior, based on adrenal gland scoring scale. However, there was no overt metastasis. After surgery, his symptoms resolved and abnormal laboratory tests were normalized.

Effect of ionizing radiation at low dose on transgenerational carcinogenesis by epigenetic regulation / 한국실험동물학회지

The objective of this study was to determine the effect of ionizing radiation (IR) exposure of parents on carcinogenesis of the next generation focusing on the epigenetic perspective to clarify the relationship between radiation dose and carcinogenesis in F1 generation SD rats. F1 generations from pregnant rats (F0) who were exposed to gamma rays were divided into three groups according to the dose of radiation: 10 rad, 30 rad, and untreated. They were intraperitoneally injected with 50 mg/kg of diethylnitrosamine (DEN). Carcinogenesis was analyzed by examining expression levels of tumor suppressor genes (TSG) and other related genes by methylation-specific polymerase chain reaction (MSP). DNA methylation in liver tissues was evaluated to discern epigenetic regulation of transgenerational carcinogenesis vulnerability following IR exposure. Numerous studies have proved that transcriptional inactivation due to hypermethylation of TSG preceded carcinogenesis. Results of this study revealed hypermethylation of tumor suppressor gene SOCS1 in group treated with 30 rad. In addition, genes related to DNA damage response pathway (GSTP1, ATM, DGKA, PARP1, and SIRT6) were epigenetically inactivated in all DEN treated groups. In the case of proto-oncogene c-Myc, DNA hypermethylation was identified in the group with low dose of IR (10 rad). Results of this study indicated that each TSG had different radiation threshold level (dose-independent way) and DEN treatment could affect DNA methylation profile irrelevant of ionizing radiation dose.

Estrogen receptor-α, progesterone receptor, and c-erbB/HER-family receptor mRNA detection and phenotype analysis in spontaneous canine models of breast cancer

Well characterized, stable, p16-defective canine mammary cancer (CMT) cell lines and normal canine mammary epithelial cells were used to investigate expression of the major breast cancer-specific hormone receptors estrogen receptor alpha (ER1) and progesterone receptor (PR) as well as luminal epithelial-specific proto-oncogenes encoding c-erbB-1 (epidermal growth factor receptor/EGFr), c-erbB-2/HER2, c-erbB-3, and c-erbB-4 receptors. The investigation developed and validated quantitative reverse transcriptase polymerase chain reaction assays for each transcript to provide rapid assessment of breast cancer phenotypes for canine cancers, based on ER1, PR, and c-erbB-2/HER2 expressions, similar to those in human disease. Roles for relatively underexplored c-erbB-3 and c-erbB-4 receptor expressions in each of these breast cancer phenotypes were also evaluated. Each quantitative assay was validated by assessment of amplicon size and DNA sequencing following amplification. Differential expression of ER1, PR, and c-erbB-2 in CMT cell lines clearly defined distinct human-like breast cancer phenotypes for a selection of CMT-derived cell lines. Expression profiles for EGFr family genes c-erbB-3 and c-erbB-4 in CMT models also provided an enriched classification of canine breast cancer identifying new extended phenotypes beyond the conventional luminal-basal characterization used in human breast cancer.

GAB2 Amplification in Squamous Cell Lung Cancer of Non-Smokers

Lung squamous cell cancer (SCC) is typically found in smokers and has a very low incidence in non-smokers, indicating differences in the tumor biology of lung SCC in smokers and non-smokers. However, the specific mutations that drive tumor growth in non-smokers have not been identified. To identify mutations in lung SCC of non-smokers, we performed a genetic analysis using arrays comparative genomic hybridization (ArrayCGH). We analyzed 19 patients with lung SCC who underwent surgical treatment between April 2005 and April 2015. Clinical characteristics were reviewed, and DNA was extracted from fresh frozen lung cancer specimens. All of copy number alterations from ArrayCGH were validated using The Cancer Genome Atlas (TCGA) copy number variation (CNV) data of lung SCC. We examined the frequency of copy number changes according to the smoking status (non-smoker [n = 8] or smoker [n = 11]). We identified 16 significantly altered regions from ArrayCGH data, three gain and four loss regions overlapped with the TCGA lung squamous cell carcinoma (LUSC) patients. Within these overlapped significant regions, we detected 15 genes that have been reported in the Cancer Gene census. We also found that the proto-oncogene GAB2 (11q14.1) was significantly amplified in non-smokers patients and vice versa in both ArrayCGH and TCGA data. Immunohistochemical analyses showed that GAB2 protein was relatively upregulated in non-smoker than smoker tissues (37.5% vs. 9.0%, P = 0.007). GAB2 amplification may have an important role in the development of lung SCC in non-smokers. GAB2 may represent a potential biomarker for lung SCC in non-smokers.

Pheochromocytoma Developed in a Boy with Multiple Endocrine Neoplasia Type 2A Confirmed by the RET Proto-Oncogene Mutation / 임상소아혈액종양

A 9-year-old boy presented with increased sweating and abdominal pain. His mother and uncle had been diagnosed with bilateral pheochromocytoma and medullary thyroid carcinoma. Magnetic resonance imaging of the boy's abdomen revealed a 7.5 cm×7.0 cm×6.0 cm mass with a thick peripheral enhancing wall and fluid-fluid level at the right suprarenal region. His ¹²³I-meta-iodobenzylguanidine (MIBG) scan showed a large mass with increased MIBG uptake in the right adrenal gland. The levels of serum norepinephrine, urine epinephrine/norepinephrine, metanephrine, and vanillylmandelic acid were elevated. He, his mother, and two sisters tested positive for the known mutation of multiple endocrine neoplasia type 2A, Cys634Tyr in RET proto-oncogene. Laparoscopic tumor excision and right adrenalectomy were performed. Final diagnosis was pheochromocytoma with malignant behavior, based on adrenal gland scoring scale. However, there was no overt metastasis. After surgery, his symptoms resolved and abnormal laboratory tests were normalized.

Comparison of Changes in the Interstitial Cells of Cajal and Neuronal Nitric Oxide Synthase-positive Neuronal Cells With Aging Between the Ascending and Descending Colon of F344 Rats

BACKGROUND/AIMS: Neuronal degeneration and changes in interstitial cells of Cajal (ICCs) are important mechanisms of age-related constipation. This study aims to compare the distribution of ICCs and neuronal nitric oxide synthase (nNOS) with regard to age-related changes between the ascending colon (AC) and descending colon (DC) in 6-, 31-, and 74-week old and 2-year old male Fischer-344 rats. METHODS: The amount of fecal pellet and the bead expulsion times were measured. Fat proportion in the muscle layer of the colon was analyzed by hematoxylin and eosin staining. Proto-oncogene receptor tyrosine kinase (KIT) and neuronal nitric oxide synthase (nNOS) expression were analyzed with Western blotting and immunohistochemistry. Isovolumetric contractile measurements and electrical field stimulation were used to assess smooth muscle contractility. RESULTS: Colon transit and bead expulsion slowed with senescence. Fat in the muscle layer accumulated with age in the AC, but not in the DC. The proportion of KIT-immunoreactive ICCs in the submucosal and myenteric plexus was higher in the DC than in the AC, and it declined with age, especially in the AC. In contrast, the proportion of NOS-immunoreactive neurons in the myenteric plexus was higher in the AC than in the DC, and both decreased in older rats. Nitric oxide levels declined with age in the DC. Muscle strip experiments showed that the inhibitory response mediated by nitric oxide in the circular direction of the DC was reduced in 2-year old rats. CONCLUSION: The AC and DC differ in their distribution of ICCs and nNOS, and age-related loss of nitrergic neurons more severely affects the DC than the AC.

Clinical and genetic features of a patient with myeloid neoplasm in association with PDGFRA and EVI1 gene rearrangements / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>Todelineate the clinical and genetic features of a patient with myeloproliferative neoplasm (MPN) in association with PDGFRA and EVI1 genes rearrangements.</p><p><b>METHODS</b>Clinical data of the patient was collected. Conventional cytogenetics, fluorescence in situ hybridization (FISH) and nested PCR were carried out for the patient.</p><p><b>RESULTS</b>The patient has featured recurrent rash, joint pain, and intermittent fever. Laboratory tests showed hyperleukocytosis and marked eosinophilia. Physical examination revealed splenomegaly. His karyotype was 46,XY,t(3;5)(q26;q15)[6]/46,XY[10]. FISH assay showed that both PDGFRA and EVI1 genes were rearranged. Molecular studies of the mRNA suggested that there was a in-frame fusion between exon 12 of the PDGFRA gene and exon 9 of the FIP1L1 gene. Imatinib was initiated at a dosage of 200 mg, and after 10 months, the signal of the FIP1L1-PDGFRA fusion gene was undetectable in bone marrow sample. However, the expression of EVI1 mRNA was stable, with no significant difference found between the patient and 10 healthy controls.</p><p><b>CONCLUSION</b>MPN in association with PDGFRA and EVI1 genes rearrangements have unique clinical and genetic features. Genetic testing is helpful for early diagnosis. Imatinib may be effective for the treatment.</p>

Expression of the c-MET, HGF and VEGF biomarkers in intestinal and diffuse gastric cancer in the Brazilian population: a pilot study for the standardization of the quantitative PCR technique

Background: Gastric carcinoma (GC) is the third leading cause of death among malignant tumors worldwide, causing approximately 900,000 deaths/year. Changes in oncogenes that encode tyrosine kinase receptors play an important role in the pathogenesis of GC. MET gene is a proto-oncogene that encodes a tyrosine kinase receptor c-MET and it is required for embryonic development and tissue repair. The hepatocyte growth factor (HGF) is the only known ligand for c-Met receptor. The MET oncogene activation suppresses apoptosis and promotes the survival, proliferation, migration, differentiation and angiogenesis of cells. Among the angiogenic factors, VEGF is the main regulator. Its biological function includes the promotion of endothelial cells mitosis to stimulate cells proliferation. These biomarkers expression in GC is relatively recent and population-based studies are required to define the expression pattern. The aim of this study was to determine qPCR technical standardization to evaluate quantitatively, in paraffin tissue samples, the presence of gene 23 expression of the MET, HGF and VEGF in diffuse and intestinal GC types. Methods: Twenty GC patients were studied, 10 patients were intestinal-type GC (average age 72.1 years) and 10 diffuse-type (average age 50.1 years). In all patients, tissue samples were analyzed from the tumor and distant areas of the tumor tissue. The relative expressions of the tumor markers c-Met, HGF and VEGF were performed by qPCR technique by comparing tumor and non-tumoral samples and they were normalized with the GAPDH constitutive gene. Statistical analysis was performed through T-test. Results: For c-Met, 18/20 (90%) patients expressed the marker and 9/20 (45%) overexpressed this gene, in which three were intestinal-type GC and six were diffuse-type GC. For HGF, only 7/20 (35%) patients expressed this gene and it was overexpressed in 4/20 (20%), in which two were intestinal-type GC and two were diffuse-type GC. For VEGF, 20/20 (100%) patients expressed this marker and in 12/20 (60%) were observed overexpression, in which eight patients had diffuse-type GC and four had intestinal-type GC. Conclusions: qPCR technique was standardized and suitable for expression analysis of the three biomarkers using paraffin embedded tissue samples. Further studies should be carried out to characterize the expression pattern of these biomarkers in GC in the Brazilian population (AU)

Inhibition of c-Yes Induces Differentiation of HT-29 Human Colon Cancer Stem Cells through Midbody Elongation

Recent research suggests that a small group of cells, named cancer stem cells (CSCs), is responsible for initiating tumor formation, recurrence, and metastasis. c-Yes, a proto-oncogene that is a subfamily of Src family kinase, is often activated in human colon cancer; this implicates c-Yes in the onset and progression of the disease. The objective of this study was to investigate the correlation between c-Yes and CSCs. We performed a sphere formation assay and reverse transcription-polymerase chain reaction for studying the differentiation of HT-29 human colon CSCs. To demonstrate the specific role of c-Yes in CSCs, we performed live cell microscopy and a cell cycle assay. These study shows, for the first time, that c-Yes is enriched in CD133+ CSCs, compared to their CD133− counterparts, and that c-Yes depletion in CD133+ cells induces cell differentiation. Moreover, c-Yes depletion was found to elongate the midbody and increase the proliferation doubling time. This also suggested that the misregulation of microtubules during chromosomal separation causes aneuploidy. Our results suggest that c-Yes may play a crucial role in initiating, maintaining, and driving the tumorigenic property of colon cancer.

VEGF and Ki-67 Overexpression in Predicting Poor Overall Survival in Adenoid Cystic Carcinoma / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: The purpose of this study was to evaluate potential prognostic factors in patients with adenoid cystic carcinoma (ACC). MATERIALS AND METHODS: A total of 68 patients who underwent curative surgery and had available tissue were enrolled in this study. Their medical records and pathologic slides were reviewed and immunohistochemistry for basic fibroblast growth factor, fibroblast growth factor receptor (FGFR) 2, FGFR3, c-kit, Myb proto-oncogene protein, platelet-derived growth factor receptor beta, vascular endothelial growth factor (VEGF), and Ki-67 was performed. Univariate and multivariate analysis was performed for determination of disease-free survival (DFS) and overall survival (OS). RESULTS: In univariate analyses, primary site of nasal cavity and paranasal sinus (p=0.022) and Ki-67 expression of more than 7% (p=0.001) were statistically significant factors for poor DFS. Regarding OS, perineural invasion (p=0.032), high expression of VEGF (p=0.033), and high expression of Ki-67 (p=0.007) were poor prognostic factors. In multivariate analyses, primary site of nasal cavity and paranasal sinus (p=0.028) and high expression of Ki-67 (p=0.004) were independent risk factors for poor DFS, and high expression of VEGF (p=0.011) and Ki-67 (p=0.011) showed independent association with poor OS. CONCLUSION: High expression of VEGF and Ki-67 were independent poor prognostic factors for OS in ACC.

Perfil de expressão de microRNAs regulados por C-MYC no linfoma de Burkitt / [Expression profile of C-MYC-regulated microRNAs in Burkitt's lymphoma]

O Linfoma de Burkitt (LB), subtipo de linfoma não Hodgkin B mais frequente na infância, é uma neoplasia hematológica altamente agressiva. A assinatura molecular é a translocação (8;14) ou suas variantes: t(2;8) e t(8;22). Ambas as translocações envolvem o proto-oncogene c-MYC que quando translocado é expresso constitutivamente, caracterizando a principal alteração conhecida no LB. Atualmente, tem sido demonstrado que c-MYC regula a expressão de vários miRNAs, dentre eles o cluster de miR-17-92 e a família miR-34, entreoutros. Neste contexto, o balanço entre c-MYC e miRNAs parece ser crítico para a patogênese do LB e necessita ser melhor elucidado. Nesse estudo avaliamos a expressão dos miRNAs regulados por c-MYC (cluster 17-92: miR-17, miR-19a/b, miR-20a, miR-92a e da família miR-34) em 57 amostras tumorais de LB pediátrico. Adicionalmente, avaliamos a correlação entre os níveis de miR-17, miR-19a/b, miR-20a e miR-92a e a expressão de um dos seus principais alvos, a proteína pró-apoptótica BIM. Foi observado que níveis elevados do miR-17 e miR-20a estavam associados com a ausência da expressão de BIM (p<0,001). Em sequência, observamos que o aumento do miR-17 estava fortemente correlacionado com uma sobrevida global (SG) inferior (p=0,007). A análise multivariada revelou também que miR-17 foi um preditor significativo de SG encurtada. A inibição do miR-17 em linhagem de LB resultou em aumento da proteína BIM, reforçando o papel deste miRNA na regulação deBIM...

Burkitt lymphoma (BL) is highly aggressive subtype of B-non-Hodgkin more frequent in childhood and associated with the translocation (8, 14) or its variations: t(2, 8) or t(8, 22). The proto-oncogene c-MYC is involved in all translocations and it is juxtaposed to Igs gene enhancers being expressed constitutively. It has been demonstrated that c-MYC regulates alarge number of miRNAs, including the cluster miR-17-92 and miR-34 family. Thus, the balance between Myc and miRNAs may be critical to the BL pathogenesis and needs furtherelucidation. In this study, we investigated miR-17, miR-19a, miR-19b, miR-20 and miR-92a expression levels in a series of 57 BL tumor samples. In addition, pro-apoptotic BIM proteinexpression was evaluated and then compared to miR-17, miR-19a, miR-19b, miR-20 and miR-92a levels, and patient outcomes. We found that upregulated expression of miR-17, andmiR-20a correlates with lack of pro-apoptotic BIM protein expression (p<0.001). Patients bearing tumors with upregulated miR-17 displayed decreased overall survival (OS) (p=0.007). Moreover, the multivariate analysis revealed that miR-17 was a significant predictor of shortened OS. Using hairpin inhibitor we showed that inhibition of miR-17 resulted inenhanced BIM expression in a BL cell line, suggesting the involvement of this miRNA in the regulation of BIM protein. Besides, low expression levels of miR-34a/b/c were observed in BL tumor samples. Next, we evaluated whether these miRNAs were suppressed by DNAmethylation. So, we analyzed the effect of demethylant agent 5-aza-2-deoxycytidine (decitabine) on miR-34 expression levels in BL cell lines. We observed an increase of miR-34b levels in BL41, Daudi and Raji cell lines in all decitabine concentrations. Then, we also detected that the treatment with higher concentration of decitabine resulted in the c-MYCmRNA reduction in Daudi and Raji (0.83 and 1.4 times, respectively)...

Clonagem molecular do oncogene EZH2 de leucemiamieloide crônica e perspectivas terapêuticas / Molecular cloning of EZH2 oncogene in chronic myeloid leukemia andtherapeutic prospects

A Leucemia Mieloide Crônica (LMC) é uma neoplasia mieloproliferativa originada, em 95% dos casos, por uma anormalidadecitogenética que se caracteriza pela translocação recíproca entre os cromossomos 9 e 22 t(9; 22) (q34; q11), resultandono cromossomo Philadelphia (Ph). Considerando que a cura da LMC só é possível com um transplante de medulaóssea bem-sucedido e que existem casos de resistência ao inibidor de tirosina quinase Mesilato de Imatinibe, fármacode primeira escolha para o tratamento, é importante que se conheça detalhadamente os genes e proteínas alterados naLMC, favorecendo a efetividade de estratégias terapêuticas, a otimização do diagnóstico e a detecção de doença residualmínima. Dentre as novas abordagens terapêuticas para a LMC está a terapia gênica, que dependendo do gene alvo, podetambém ser eficiente para o tratamento de outras neoplasias. Dentro deste contexto, os objetivos do trabalho foram:realizar a clonagem molecular de um fragmento de DNA do gene EZH2, alvo promissor da terapia gênica, que provocaalteração epigenética na LMC e em diversas neoplasias; bem como contribuir para outros trabalhos de manipulação gênicainterespécies, os quais tem grande contribuição para a área da saúde. Para isso, o gene EZH2 foi isolado a partir do DNAgenômico de sangue periférico de pacientes com LMC e posteriormente clonado em sistemas procariotos. Dessa forma,foram realizados, definidos e comprovados os procedimentos de manipulação gênica interespécies e discutido o futuro dabiotecnologia no auxílio a pesquisas e a tratamentos, com foco na LMC.

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasia, caused in 95 % of the cases by a cytogenetic abnormalitycharacterized by the reciprocal translocation between chromosomes 9 and 22 t(9; 22) (q34; q11), resulting in Philadelphiachromosome (Ph).Considering that CML cure is only possible with a successful bone marrow transplantation and that thereare resistance cases to the tyrosine kinase inhibitor Imatinib Mesylate, prescribed in first line drug treatment; it is importantto know in detail the genes and proteins that are possibly altered in CML, favoring effective therapeutic strategies, optimizeddiagnosis and minimal residual disease detection. Among the new therapeutic approaches to CML is gene therapy, which,depending on the target gene, can be efficient to other neoplasms treatment. In this context, the aims of this work were:to proceed the molecular cloning of a DNA fragment from EZH2 gene, potential target for gene therapy, that promotesepigenetic alteration in CML and in many neoplasms; as well as to contribute to studies related to interspecies gene transferthat have high contribution to health. For this reason, the EZH2 gene was isolated from peripheral blood genomic DNAfrom CML patients and cloned in prokaryotic systems. Therefore, in this study, we proceed, defined and proved the interspeciesgene transfer procedures and discussed the future of biotechnology in researches and treatments, especially in CML.

[Common KRAS and BRAF mutations in colorectal cancer patients]

KRAS and BRAF gene mutations are considered as key events in carcinogenesis progression of colorectal cancer. Given the importance of these gene mutations evaluations, especially in metastatic patients, in terms of determination of therapeutic strategies, we studied the prevalence of KRAS and BRAF mutations in Tabriz city. Deoxyribonucleic Acid [DNA] extracted from Fresh tumor and normal tissues of 30 primary CRC patients. Direct sequencing method, was the method for determining the mutation points of KRAS exon 2 and BRAF exon 15 genes. After mutation analysis, the clinical and pathological associations of mutant genes were assessed. The prevalence of KRAS gene mutation was 20 %[6 out of 30 cases] in this study, and none of patients had the mutant BRAF gene. The odds ratio of the KRAS gene mutation in high grade CRCs was 2.1[95% CI: 1.34 to 3.29]. The same ratio for metastasis was 1.1[95% CI: 0.93 to 1.25]. There was no significant relationship between the mutation and clinical and pathological aspects of the disease. The high occurrence of early onset of colorectal cancer in Iran demands more attention to screening and prevention programs in the younger age group in the country. However further genetic studies are needed at the molecular level and large population in different geographical areas