Phenotypic heterogeneity in individuals with MECOM variants in 2 families

MECOM encodes the transcriptional regulators, EVI1 and MDS1-EVI1, from two distinct transcription start sites. EVI1 plays important roles in hematopoiesis and stem cell self-renewal. Recently, our group and others revealed that individuals with MECOM variants present diverse hematological and skeletal defects, including radioulnar synostosis (RUS). In the present study, we analyzed two families suspected with MECOM-associated syndrome. In family 1, a MECOM splicing variant (c.2285+1G>A) was identified in an individual with bone marrow failure (TRS4) without RUS and her mother, who had mild leukocytopenia, thrombocytopenia, and bilateral RUS. A copy neutral loss of heterozygosity decreasing the variant allele frequency was observed in the bone marrow of TRS4 and the peripheral blood leukocytes of her mother. However, TRS4 remained transfusion-dependent. In family 2, a MECOM variant (c.2208-4A>G), which was predicted to cause a cryptic acceptor site that results in a 3-base insertion (an insertion of Ser) in the mRNA, was identified in the proband, with bone marrow failure; this variant was also observed in her brother and father, both of whom have skeletal malformations, but no cytopenia. RT-PCR using leukocytes revealed a transcript with a 3-bp insertion in the proband, her brother, and the father, suggesting that the transcript variant with a 3-bp insertion is independent of blood phenotype. Collectively, these results suggest the presence of intrafamilial clinical heterogeneity in both families with MECOM splicing variants. Somatic genetic event may complicate the understanding of clinical variability among family members.

MLL-SEPT6 Positive Acute Myeloid Leukemia Patients Often Co-occur With NRAS Mutations?

BackgroundThe MLL-SEPT6 fusion gene is a relatively rare genetic event in leukemia. Its clinical characteristics, prognosis, especially the profile of co-occurring gene mutations remain unclear. MethodsWe retrospectively analyzed four rare leukemia cases carrying MLL-SEPT6 in our hospital from laboratory examination, diagnosis, treatment and prognosis, and provided a comprehensive and detailed description on clinical profile of MLL-SEPT6-positive AML patients in the literature. ResultsAll the four patients were diagnosed with acute myeloid leukemia (AML) and harbored X chromosome and 11 chromosome rearrangements. Three of four cases occurred NRAS mutation while the rest one with congenital AML did not. Of the four cases, one developed drug-resistant, one suffered relapse after bone marrow transplantation (BMT) and one died. Combined with other cases reported in literatures, we found that of all patients diagnosed with AML, 90.9% were children (≤ 9 years old) and 54.5% were infants (≤1 year old). The survival time between infant group (≤1 year old) and pediatric group (>1 and <18 years old), patients that received BMT and that received chemotherapy alone did not show significant differences (P>0.05). ConclusionsMLL-SEPT6 was more commonly observed in pediatric AML patients, some of which may co-occur with NRAS mutations. The prognosis was inconclusive and may not be related to age or BMT. More information needs to be accumulated and summarized from additional cases to confirm the underlying connection between NRAS mutations and MLL-SEPT6 in order to better understand the profile in MLL-SEPT6-positive AML.

Cognitive Archaeology and the Cognitive Sciences

Cognitive archaeology uses cognitive and psychological models to interpret the archaeological record. This chapter outlines several components that may be essential in building effective cognitive archaeological arguments. It also presents a two-stage perspective for the development of modern cognition, primarily based upon the work of Coolidge and Wynn. The first describes the transition from arboreal to terrestrial life in later Homo and the possible cognitive repercussions of terrestrial sleep. The second stage proposes that a genetic event may have enhanced working memory in Homo sapiens (specifically in terms of Baddeley’s multicomponent working memory model). The present chapter also reviews the archaeological and neurological bases for modern thinking, and the latter arguments are primarily grounded in the significance of the morphometric rescaling of the parietal lobes, which appears to have distinguished Homo sapiens from Neandertals.

The Loss of Heterozygosity of FHIT Gene in Sporadic Breast Cancer

The loss of heterozygosity (LOH) is a genetic event that can change gene function. FHIT is a potential tumor suppressor gene. Although the precise FHIT molecular mechanism of action is not well understood, evidences suggest that Fhit protein reduced levels are involved in mammary carcinogenesis. The aim of this study was to investigate if FHIT LOH could influence on sporadic breast cancer (BC) biological behavior, through its association with prognostic factors for sporadic BC.Tumor tissue and peripheral blood samples were analyzed using the microsatellite marker D3S1300. The findings were associated with clinicopathological parameters including overall survival. LOH was detected in 31.1%(52/167) of the informative BC’ cases. Considering clinical and pathological characteristics we have found no significant association with FHIT LOH status. The mean follow-up time was 80 months. After the Cox regression analysis two parameters remained associated with BC’s risk of death: TNM stage III and IV - HR = 3.74(95% CI, 1.16-12.1) P=0.027 and disease relapse HR = 3.14(CI 95% 1.26-7.80) P =0.014. This study shows that FHIT LOH by itself is not a prognostic factor for sporadic BC. Further researches are required to elucidate the functional role of FHIT LOH concerning to BC.

Can TP53-mutant follicular adenoma be a precursor of anaplastic thyroid carcinoma?

Mutations of the TP53 tumor suppressor gene are highly prevalent in thyroid anaplastic carcinomas (AC) but are also reported in some well-differentiated cancers and even benign adenomas. The natural history of TP53-mutant adenomas, and whether they may represent a precursor for well-differentiated cancer or AC is largely unknown. Similarly, the frequency of TP53 mutations in thyroid nodules found on routine molecular analysis of fine-needle aspiration (FNA) samples is not established. A database on 44,510 FNA samples from thyroid nodules with predominantly indeterminate cytology tested using ThyroSeq v3 was reviewed to identify TP53-mutant cases and analyze their genetic profile and available clinicopathological findings. Among 260 (0.6%) selected thyroid nodules, 36 had an isolated TP53 mutation, and 224 carried a combination of TP53with other genetic alterations. No significant difference was observed between these groups with respect to patient age, gender, nodule size, and spectrum of TP53mutations. Histopathologically, 86% of the resected nodules with isolated TP53mutations were benign (mostly adenomas), whereas 82% of nodules carrying TP53mutations co-occurring with other alterations were cancers (P=0.001), including de-differentiated AC. TP53-mutant benign tumors and well-differentiated cancers often had scattered single neoplastic cells with bizarre nuclei resembling those comprising AC. Our study demonstrates that a small but distinct proportion of thyroid nodules carry a TP53mutation, either as a single genetic event or in combination with other alterations. While the latter are mostly cancers prone to dedifferentiation, there is at least a theoretical possibility that TP53-mutated adenomas may represent a precursor for such cancers, including AC.

The transcriptional landscape of Shh medulloblastoma

Sonic hedgehog medulloblastoma encompasses a clinically and molecularly diverse group of cancers of the developing central nervous system. Here, we use unbiased sequencing of the transcriptome across a large cohort of 250 tumors to reveal differences among molecular subtypes of the disease, and demonstrate the previously unappreciated importance of non-coding RNA transcripts. We identify alterations within the cAMP dependent pathway (GNAS, PRKAR1A) which converge on GLI2 activity and show that 18% of tumors have a genetic event that directly targets the abundance and/or stability of MYCN. Furthermore, we discover an extensive network of fusions in focally amplified regions encompassing GLI2, and several loss-of-function fusions in tumor suppressor genes PTCH1, SUFU and NCOR1. Molecular convergence on a subset of genes by nucleotide variants, copy number aberrations, and gene fusions highlight the key roles of specific pathways in the pathogenesis of Sonic hedgehog medulloblastoma and open up opportunities for therapeutic intervention.

EWSR1-ATF1 Fusion in a Myoepithelial Carcinoma of Soft Tissue With Small Round Cell Morphology: A Potential Diagnostic Pitfall

Myoepithelial tumors of soft tissue are rare mesenchymal neoplasms that overlap with their salivary gland and skin counterparts at both the histopathologic and molecular levels. EWSR1 gene rearrangements with various fusion partners represent a common genetic event in myoepithelial tumors of soft tissue, whether benign or malignant, and may prove useful as a diagnostic tool in difficult cases. However, the number of diagnostic entities with EWSR1 gene rearrangements has grown considerably in recent years, and there is significant morphologic and immunophenotypic overlap amongst this group, underscoring the importance of fusion testing to detect fusion partners that are characteristic of discrete diagnostic entities. Herein, we report a malignant myoepithelial tumor of soft tissue/myoepithelial carcinoma with an undifferentiated round cell morphology arising in a pediatric patient with a EWSR1-ATF1 gene fusion.

Eicosapentaenoic Acid Inhibits KRAS Mutant PancreaticCancer Cell Growth by Suppressing Hepassocin Expression and STAT3 Phosphorylation

Background: The oncogenic Kirsten rat sarcoma viral oncogene homolog (KRAS) mutation was reported to be the signature genetic event in most cases of pancreatic ductal adenocarcinoma (PDAC). Hepassocin (HPS/FGL1) is involved in regulating lipid metabolism and the progression of several cancer types; however, the underlying mechanism of HPS/FGL1 in the KRAS mutant PDAC cells undergoing eicosapentaenoic acid (EPA) treatment remains unclear. Methods: We measured HPS/FGL1 protein expressions in a human pancreatic ductal epithelial (HPNE) normal pancreas cell line, a KRAS-wild-type PDAC cell line (BxPC-3), and KRAS-mutant PDAC cell lines (PANC-1, MIA PaCa-2, and SUIT-2) by Western blot methods. HEK293T cells were transiently transfected with corresponding KRAS-expressing plasmids to examine the level of HPS expression with KRAS activation. We knocked-down HPS/FGL1 using lentiviral vectors in SUIT-2 cells and measured the cell viability by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and clonogenicity assays. Furthermore, a lipidomic analysis was performed to profile changes in lipid metabolism after HPS/FGL1 knockdown. Results: We found that the HPS/FGL1 level was significantly upregulated in KRAS-mutated PDAC cells and was involved in KRAS/phosphorylated (p)-signal transduction and activator of transcription 3 (STAT3) signaling, and the knockdown of HPS/FGL1 in SUIT-2 cells decreased cell proliferation through increasing G2/M cell cycle arrest and cyclin B1 expression. In addition, the knockdown of HPS/FGL1 in SUIT-2 cells significantly increased omega-3 polyunsaturated fatty acids (PUFAs) and EPA production but not docosahexaenoic acid (DHA). Moreover, EPA treatment in SUIT-2 cells reduced the expression of de novo lipogenic protein, acetyl coenzyme A carboxylase (ACC)-1, and decreased p-STAT3 and HPS/FGL1 expressions, resulting in the suppression of cell viability. Conclusions: Results of this study indicate that HPS is highly expressed by KRAS-mutated PDAC cells, and HPS/FGL1 plays a crucial role in altering lipid metabolism and increasing cell growth in pancreatic cancer. EPA supplements could potentially inhibit or reduce ACC-1-involved lipogenesis and HPS/FGL1-mediated cell survival in KRAS-mutated pancreatic cancer cells.

Distinct functions of transforming growth factor-β signaling in c-MYC driven hepatocellular carcinoma initiation and progression

Dysregulation of transforming growth factor-beta (TGFβ) signaling has been implicated in liver carcinogenesis with both tumor promoting and inhibiting activities. Activation of the c-MYC protooncogene is another critical genetic event in hepatocellular carcinoma (HCC). However, the precise functional crosstalk between c-MYC and TGFβ signaling pathways remains unclear. In the present investigation, we investigated the expression of TGFβ signaling in c-MYC amplified human HCC samples as well as the mechanisms whereby TGFβ modulates c-Myc driven hepatocarcinogenesis during initiation and progression. We found that several TGFβ target genes are overexpressed in human HCCs with c-MYC amplification. In vivo, activation of TGFβ1 impaired c-Myc murine HCC initiation, whereas inhibition of TGFβ pathway accelerated this process. In contrast, overexpression of TGFβ1 enhanced c-Myc HCC progression by promoting tumor cell metastasis. Mechanistically, activation of TGFβ promoted tumor microenvironment reprogramming rather than inducing epithelial-to-mesenchymal transition during HCC progression. Moreover, we identified PMEPA1 as a potential TGFβ1 target. Altogether, our data underline the divergent roles of TGFβ signaling during c-MYC induced HCC initiation and progression.

Targeting Loss of Heterozygosity: A Novel Paradigm for Cancer Therapy

Loss of heterozygosity (LOH) is a common genetic event in the development of cancer. In certain tumor types, LOH can affect more than 20% of the genome, entailing loss of allelic variation in thousands of genes. This reduction of heterozygosity creates genetic differences between tumor and normal cells, providing opportunities for development of novel cancer therapies. Here, we review and summarize (1) mutations associated with LOH on chromosomes which have been shown to be promising biomarkers of cancer risk or the prediction of clinical outcomes in certain types of tumors; (2) loci undergoing LOH that can be targeted for development of novel anticancer drugs as well as (3) LOH in tumors provides up-and-coming possibilities to understand the underlying mechanisms of cancer evolution and to discover novel cancer vulnerabilities which are worth a further investigation in the near future.