Letter to the editor Recurrent KRAS G12V pathogenic mutation in adenomatoid odontogenic tumours Dear Editor, The adenomatoid odontogenic tumour (AOT) is a non-aggressive encapsulated tumour, being usually diagnosed in association with an unerupted permanent maxillary canine [1,2]. There are scarce reports of multiple AOTs [3-5] and a patient with Schimmelpenning syndrome (SS) with AOT was reported [6]. SS is characterized by sebaceous nevi, associated with ipsilateral abnormalities of the central nervous system, resulting from postzygotic autosomal dominant HRAS or KRAS lethal mutations that survive by somatic mosaicism [7]. RAS mutations were previously reported in lesional tissue (including nevus sebaceous) of a patient, but not in normal skin or blood leukocytes, consistent with a somatic mosaicism [7]. We evaluated one AOT sample from a SS patient having multiple AOTs (index patient) and two sporadic AOTs (samples #1 and #2) for mutations in a panel of 50 oncogenes and tumour suppressor genes, including RAS family, by using Ion AmpliSeq TM Cancer Hotspot Panel v2 (Life Technologies, Carlsbad, USA). After filtering by missense variants, candidate variants from the panel were defined as those pathogenic variants in regions with a depth greater than X500 and frequency greater than 5%. Only KRASc.35G > T (KRASG12V) fit this criteria, and was validated by TaqMan Ò Mutation Detection Assay using the probes KRAS_476_mu and KRAS_rf (Applied Biosystems, Foster City, USA). We further interrogated the KRASG12V mutation in six extra AOTs (samples #3-8) by the TaqMan Ò Assay. This KRAS mutation was detected in the three samples, as well as in four (samples #3, #4, #5 and #7) out of six additional samples. The mutation was validated by Sanger sequencing (Fig. 1). No other pathogenic mutation interrogated was detected. Blood leukocytes from the index patient were negative for KRASG12V mutation. To determine the specificity of the KRASG12V mutation in the context of odontogenic tumours, we evaluated three ameloblastomas, two dentinogenic ghost cell tumours and two normal oral mucosa samples using the TaqMan Ò Assay, being all negative for the mutation. Constitutively activation of the MAPK pathway by BRAFV600E mutation was reported in ameloblastoma [8-10], and in ameloblastic carcinoma [11]. We describe a recurrent oncogenic mutation in an upstream activator of MAPK, KRAS, in AOT. RAS mutations are found in 30% of human cancers and 80% of KRAS mutations occur at codon 12, being highly frequent in lung adenocarcinoma, pancreatic and colon carcinomas [12]. In our series, seven out of nine AOTs exhibited the KRASG12V mutation. The KRAS mutation was identified in the index patient sample and in sporadic AOTs, a candidate to driver mutation in these lesions. Driver mutations confer growth advantage to tumour cells and are positively selected during cancer evolution [13].

Cardiac cachexia (CC) is a common complication of heart failure (HF) associated with muscle wasting and poor patient prognosis. Although different mechanisms have been proposed to explain muscle wasting during CC, its pathogenesis is still not understood. Here, we described an integrative analysis between miRNA and mRNA expression profiles of muscle wasting during CC. Global gene expression profiling identified 1,281 genes and 19 miRNAs differentially expressed in muscle wasting during CC. Several of these deregulated genes are known or putative targets of the altered miRNAs, including miR-29a-3p, miR-29b-3p, miR-210-5p, miR-214, and miR-489. Gene ontology analysis on integrative mRNA/miRNA expression profiling data revealed miRNA interactions affecting genes that regulate extra-cellular matrix (ECM) organization, proteasome protein degradation, citric acid cycle and respiratory electron transport. We further identified 11 miRNAs, including miR-29a-3p and miR-29b-3p, which target 21 transcripts encoding the collagen proteins related to ECM organization. Integrative miRNA and mRNA global expression data allowed us to identify miRNA target genes involved in skeletal muscle wasting in CC. Our functional experiments in C2C12 cells confirmed that miR-29b down-regulates collagen genes and contributes to muscle cell atrophy. Collectively, our results suggest that key ECM-associated miRNAs and their target genes may contribute to CC in HF.

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Canine carcinomas have been considered natural models for human diseases; however, the genomic profile of canine prostate cancers (PCs) has not been explored. In this study, 14 PC androgen-receptor-negative cases, 4 proliferative inflammatory atrophies (PIA), and 5 normal prostate tissues were investigated by array-based comparative genomic hybridization (aCGH). Copy number alterations (CNAs) were assessed using the Canine Genome CGH Microarray 4 × 44K (Agilent Technologies). Genes covered by recurrent CNAs were submitted to enrichment and cross-validation analysis. In addition, the expression levels of TP53, MDM2 and ZBTB4 were evaluated in an independent set of cases by qPCR. PC cases presented genomic complexity, while PIA samples had a small number of CNAs. Recurrent losses covering well-known tumor suppressor genes, such as ATM, BRCA1, CDH1, MEN1 and TP53, were found in PC. The in silico functional analysis showed several cancer-related genes associated with canonical pathways and interaction networks previously described in human PC. The MDM2, TP53, and ZBTB4 copy number alterations were translated into altered expression levels. A cross-validation analysis using The Cancer Genome Atlas (TCGA) database for human PC uncovered similarities between canine and human PCs. Androgen-receptor-negative canine PC is a complex disease characterized by high genomic instability, showing a set of genes with similar alterations to human cancer.

Cystic endometrial hyperplasia (CEH), mucometra, and pyometra are common uterine diseases in intact dogs, with pyometra being a life threatening disease. This study aimed to determine the gene expression profile of these lesions and potential biomarkers for closed-cervix pyometra, the most severe condition. Total RNA was extracted from 69 fresh endometrium samples collected from 21 healthy female dogs during diestrus, 16 CEH, 15 mucometra and 17 pyometra (eight open and nine closed-cervixes). Global gene expression was detected using the Affymetrix Canine Gene 1.0 ST Array. Unsupervised analysis revealed two clusters, one mainly composed of diestrus and CEH samples and the other by 12/15 mucometra and all pyometra samples. When comparing pyometra with other groups, 189 differentially expressed genes were detected. SLPI, PTGS2/COX2, MMP1, S100A8, S100A9 and IL8 were among the top up-regulated genes detected in pyometra, further confirmed by external expression data. Notably, a particular molecular profile in pyometra from animals previously treated with exogenous progesterone compounds was observed in comparison with pyometra from untreated dogs as well as with other groups irrespective of exogenous hormone treatment status. In addition to S100A8 and S100A9 genes, overexpression of the inflammatory cytokines IL1B, TNF and IL6 as well as LTF were detected in the pyometra from treated animals. Interestingly, closed pyometra was more frequently detected in treated dogs (64% versus 33%), with IL1B, TNF, LBP and CXCL10 among the most relevant overexpressed genes. This molecular signature associated with potential biomarkers and therapeutic targets, such as CXCL10 and COX2, should guide future clinical studies. Based on the gene expression profile we suggested that pyometra from progesterone treated dogs is a distinct molecular entity.

BackgroundUndifferentiated Pleomorphic Sarcoma (UPS) and high-grade Leiomyosarcoma (LMS) are soft tissue tumors with an aggressive clinical behavior, frequently developing local recurrence and distant metastases. Despite several gene expression studies involving soft tissue sarcomas, the potential to identify molecular markers has been limited, mostly due to small sample size, in-group heterogeneity and absence of detailed clinical data.Materials and MethodsGene expression profiling was performed for 22 LMS and 22 UPS obtained from untreated patients. To assess the relevance of the gene signature, a meta-analysis was performed using five published studies. Four genes (BAD, MYOCD, SRF and SRC) selected from the gene signature, meta-analysis and functional in silico analysis were further validated by quantitative PCR. In addition, protein-protein interaction analysis was applied to validate the data. SRC protein immunolabeling was assessed in 38 UPS and 52 LMS.ResultsWe identified 587 differentially expressed genes between LMS and UPS, of which 193 corroborated with other studies. Cluster analysis of the data failed to discriminate LMS from UPS, although it did reveal a distinct molecular profile for retroperitoneal LMS, which was characterized by the over-expression of smooth muscle-specific genes. Significantly higher levels of expression for BAD, SRC, SRF, and MYOCD were confirmed in LMS when compared with UPS. SRC was the most value discriminator to distinguish both sarcomas and presented the highest number of interaction in the in silico protein-protein analysis. SRC protein labeling showed high specificity and a positive predictive value therefore making it a candidate for use as a diagnostic marker in LMS.ConclusionsRetroperitoneal LMS presented a unique gene signature. SRC is a putative diagnostic marker to differentiate LMS from UPS.

Breast cancer is the most common cancer in women worldwide and metastatic dissemination is the principal factor related to death by this disease. Breast cancer stem cells (bCSC) are thought to be responsible for metastasis and chemoresistance. In this study, based on whole transcriptome analysis from putative bCSC and reverse engineering of transcription control networks, we identified two networks associated with this phenotype. One controlled by SNAI2, TWIST1, BNC2, PRRX1 and TBX5 drives a mesenchymal or CSC-like phenotype. The second network is controlled by the SCML4, ZNF831, SP140 and IKZF3 transcription factors which correspond to immune response modulators. Immune response network expression is correlated with pathological response to chemotherapy, and in the Basal subtype is related to better recurrence-free survival. In patient-derived xenografts, the expression of these networks in patient tumours is predictive of engraftment success. Our findings point out a potential molecular mechanism underlying the balance between immune surveillance and EMT activation in breast cancer. This molecular mechanism may be useful to the development of new target therapies.

Undifferentiated high-grade pleomorphic sarcomas (UPSs) display aggressive clinical behavior and frequently develop local recurrence and distant metastasis. Because these sarcomas often share similar morphological patterns with other tumors, particularly leiomyosarcomas (LMSs), classification by exclusion is frequently used. In this study, array-based comparative genomic hybridization (array CGH) was used to analyze 20 UPS and 17 LMS samples from untreated patients. The LMS samples presented a lower frequency of genomic alterations compared with the UPS samples. The most frequently altered UPS regions involved gains at 20q13.33 and 7q22.1 and losses at 3p26.3. Gains at 8q24.3 and 19q13.12 and losses at 9p21.3 were frequently detected in the LMS samples. Of these regions, gains at 1q21.3, 11q12.2-q12.3, 16p11.2, and 19q13.12 were significantly associated with reduced overall survival times in LMS patients. A multivariate analysis revealed that gains at 1q21.3 were an independent prognostic marker of shorter survival times in LMS patients (HR = 13.76; P = 0.019). Although the copy number profiles of the UPS and LMS samples could not be distinguished using unsupervised hierarchical clustering analysis, one of the three clusters presented cases associated with poor prognostic outcome (P = 0.022). A relative copy number analysis for the ARNT, SLC27A3, and PBXIP1 genes was performed using quantitative real-time PCR in 11 LMS and 16 UPS samples. Gains at 1q21-q22 were observed in both tumor types, particularly in the UPS samples. These findings provide strong evidence for the existence of a genomic signature to predict poor outcome in a subset of UPS and LMS patients.