Oncogenic activation of EEF1A2 expression: a journey from a putative to an established oncogene

Protein synthesis via translation is a central process involving several essential proteins called translation factors. Although traditionally described as cellular "housekeepers," multiple studies have now supported that protein initiation and elongation factors regulate cell growth, apoptosis, and tumorigenesis. One such translation factor is eukaryotic elongation factor 1 alpha 2 (EEF1A2), a member of the eukaryotic elongation factor family, which has a canonical role in the delivery of aminoacyl-tRNA to the A-site of the ribosome in a guanosine 5'-triphosphate (GTP)-dependent manner. EEF1A2 differs from its closely related isoform, EEF1A1, in tissue distribution. While EEF1A1 is present ubiquitously, EEF1A2 replaces it in specialized tissues. The reason why certain specialized tissues need to essentially switch EEF1A1 expression altogether with EEF1A2 remains to be answered. Abnormal "switch on" of the EEF1A2 gene in normal tissues is witnessed and is seen as a cause of oncogenic transformation in a wide variety of solid tumors. This review presents the journey of finding increased expression of EEF1A2 in multiple cancers, establishing molecular mechanism, and exploring it as a target for cancer therapy. More precisely, we have compiled studies in seven types of cancers that have reported EEF1A2 overexpression. We have discussed the effect of aberrant EEF1A2 expression on the oncogenic properties of cells, signaling pathways, and interacting partners of EEF1A2. More importantly, in the last part, we have discussed the unique potential of EEF1A2 as a therapeutic target. This review article gives an up-to-date account of EEF1A2 as an oncogene and can draw the attention of the scientific community, attracting more research.

Biliverdin modulates the Nrf2/A20/eEF1A2 axis to alleviate cerebral ischemia-reperfusion injury by inhibiting pyroptosis

This study aimed to examine whether Biliverdin, which is a common metabolite of haem, can alleviate cerebral ischemia reperfusion injury (CIRI) by inhibiting pyroptosis. Here, CIRI was induced by middle cerebral artery occlusion-reperfusion (MCAO/R) in C57BL/6 J mice and modelled by oxygen and glucose deprivation/reoxygenation (OGD/R) in HT22 cells, it was treated with or without Biliverdin. The spatiotemporal expression of GSDMD-N and infarction volumes were assessed by immunofluorescence staining and triphenyltetrazolium chloride (TTC), respectively. The NLRP3/Caspase-1/GSDMD pathway, which is central to the pyroptosis process, as well as the expression of Nrf2, A20, and eEF1A2 were determined by Western-blots. Nrf2, A20, and eEF1A2 interactions were verified using dual-luciferase reporter assays, chromatin immunoprecipitation, or co-immunoprecipitation. Additionally, the role of Nrf2/A20/eEF1A2 axis in modulating the neuroprotective properties of Biliverdin was investigated using A20 or eEF1A2 gene interference (overexpression and/or silencing). 40 mg/kg of Biliverdin could significantly alleviate CIRI both in vivo and in vitro, promoted the activation of Nrf2, elevated A20 expression, but decreased eEF1A2 expression. Nrf2 can bind to the promoter of A20, thereby transcriptionally regulating the expression of A20. A20 can furthermore interacted with eEF1A2 through its ZnF4 domain to ubiquitinate and degrade it, leading to the downregulation of eEF1A2. Our studies have also demonstrated that either the knock-down of A20 or over-expression of eEF1A2 blunted the protective effect of Biliverdin. Rescue experiments further confirmed that Biliverdin could regulate the NF-κB pathway via the Nrf2/A20/eEF1A2 axis. In summary, our study demonstrates that Biliverdin ameliorates CIRI by inhibiting the NF-κB pathway via the Nrf2/A20/eEF1A2 axis. Our findings can help identify novel therapeutic targets for the treatment of CIRI.

A Case-Control Study by ddPCR of ALU 260/111 and LINE-1 266/97 Copy Number Ratio in Circulating Cell-Free DNA in Plasma Revealed LINE-1 266/97 as a Potential Biomarker for Early Breast Cancer Detection

BACKGROUND

In Western countries, breast cancer (BC) is the most common cancer in women. Early detection has a positive impact on survival, quality of life, and public health costs. Mammography screening programs have increased early detection rates, but new approaches to more personalized surveillance could further improve diagnosis. Circulating cell-free DNA (cfDNA) in blood could provide a potential tool for early diagnosis by analyzing cfDNA quantity, circulating tumor DNA mutations, or cfDNA integrity (cfDI).

METHODS

Plasma was obtained from the blood of 106 breast cancer patients (cases) and 103 healthy women (controls). Digital droplet PCR was used for the determination of ALU 260/111 bp and LINE-1 266/97 bp copy number ratio and cfDI. cfDNA abundance was calculated using copies of the EEF1A2 gene. The accuracy of biomarker discrimination was analyzed with receiver operating characteristic curve (ROC). Sensitivity analyses were performed to account for age as a potential confounder.

RESULTS

Cases had significantly lower ALU 260/111 or LINE-1 266/97 copy number ratios (median; ALU 260/111 = 0.08, LINE-1 266/97 = 0.20), compared with control (median; ALU 260/111 = 0.10, LINE-1 266/97 = 0.28) (p < 0.001). ROC analysis showed that copy number ratio discriminated cases from controls (area under the curve, AUC = 0.69, 95% CI: 0.62-0.76 for ALU and 0.80, 95% CI: 0.73-0.86 for LINE-1). ROC from cfDI confirmed the better diagnostic performance of LINE-1 compared with ALU.

CONCLUSIONS

Analysis of LINE-1 266/97 copy number ratio or cfDI by ddPCR appears to be a useful noninvasive test that could aid in early BC detection. Further studies in a large cohort are needed to validate the biomarker.

Eukaryotic Elongation Factor 1Alpha-2 (EEF1A2) Participates in the Progression of Gastric Cancer via Interaction with Heat Shock Protein B8 (HSPB8)

OBJECTIVE

The critical roles of eukaryotic elongation factor 1alpha-2 (EEF1A2) and heat shock protein B8 (HSPB8) in the carcinogenesis and progression of cancers have been well documented. However, the regulatory role of EEF1A2/HSPB8 in the development of gastric cancer (GC) have not been fully understood. This study was aimed at clarifying the biological effects of EEF1A2/HSPB8 on the malignant behaviors of GC cells and to investigate the molecular mechanism underlying the involvement of EEF1A2/HSPB8 in GC.

METHODS

In the present work, expression differences of EEF1A2 and HSPB8 in GC cells were detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot assay. Cell counting kit -8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU) staining, wound healing and transwell assays were employed to detect the proliferation, migration and invasion of GC cells. In addition, tube formation assay was adopted to assess in vitro angiogenesis of HUVECs incubated with the conditioned media (CM) of GC cells. Moreover, the interaction between EEF1A2 and HSPB8 was predicted from BioGrid database and analyzed through co-immunoprecipitation (Co-IP).

RESULTS

The present research revealed that EEF1A2 and HSPB8 were highly expressed in GC cell lines. EEF1A2 knockdown markedly suppressed the proliferation, migration and invasion of GC cells as well as in vitro angiogenesis. Furthermore, it was verified that EEF1A2 interacted with HSPB8 and positively regulated HSPB8 expression. Overexpression of HSPB8 reversed the suppressive effects of EEF1A2 knockdown on GC cell proliferation, migration, invasion and in vitro angiogenesis.

CONCLUSION

In conclusion, EEF1A2 could act as an oncogene in the development of GC via promoting HSPB8 expression.

EEF1A2 accelerates the protein translation of chemokine in rat myocardial cells induced by ischemia-reperfusion

How to reduce the damage caused by myocardial ischemia-reperfusion (IR) in a timely manner to save patients' lives is still a great clinical challenge. Although dexmedetomidine (DEX) has been reported to protect the myocardium, the regulatory mechanism of gene translation responding to IR injury and DEX protection is poorly understood. In this study, IR rat model with DEX and the antagonist yohimbine (YOH) pretreatment were established, and RNA sequencing was carried out to seek the important regulators in differential expressed genes. A series of cytokines and chemokine as well as eukaryotic translation elongation factor 1 alpha 2 (EEF1A2) were induced by IR compared to control and compromised by DEX pretreatment compared to IR, then reversed by YOH. Immunoprecipitation was conducted to identify that peroxiredoxin 1 (PRDX1) interacted with EEF1A2 and contributed to the recruitment of EEF1A2 on mRNA molecules of cytokines and chemokine. Knockdown of PRDX1 could weaken the enhancive effect of EEF1A2 for gene translation of IL6, CXCL2 and CXCL11 under the IR condition, and indeed reduce cell apoptosis of cardiomyocytes. We also determined that the RNA motif "USCAGDCU" at 5' UTR could be particularly recognized by PRDX1. Destruction of this motif at the 5' UTR of IL6, CXCL2 and CXCL11 by CRISPR-CAS9 could result in the loss occupancies of EEF1A2 and PRDX1 on the mRNA of these three genes. Our observations showed the importance of PRDX1 in the reasonable control of cytokine and chemokine expression to prevent excessive inflammatory response to cell damage.

EEF1A2 pathogenic variant presenting in an infant with failure to thrive and frequent apneas requiring respiratory support

EEF1A2 is a gene whose protein product, eukaryotic translation elongation factor 1 alpha 2 (eEF1A2), plays an important role in neurodevelopment. Reports of individuals with pathogenic variants in EEF1A2 are rare, with less than 40 individuals reported world-wide, however a common feature is the association of the variant with developmental and epileptic encephalopathy. Thus far, there have been limited reports of other organ systems or body functions affected by variants in this gene. Here, we present a case of a child with EEF1A2-related disorder who presented at 3 months of age with hypotonia, microcephaly, failure to thrive, and respiratory insufficiency with central apneas requiring respiratory support. Our case highlights the notion that the respiratory system may be highly implicated in EEF1A2-related disorder, allowing for better phenotypic characterization of the disorder.

Dilated cardiomyopathy in a patient with autosomal dominant EEF1A2-related neurodevelopmental disorder

The EEF1A2 gene encodes eukaryotic translation elongation factor 1α2, an integral component of the elongation factor complex. Heterozygous pathogenic variants in EEF1A2 are associated with neurodevelopmental disorders characterized by epilepsy, global developmental delay, and autism. To date, dilated cardiomyopathy has only been reported in two siblings with neurodevelopmental phenotypes and a homozygous missense variant in EEF1A2. This report describes a nine-year-old female patient who presented with neurodevelopmental phenotypes and dilated cardiomyopathy. Analysis of 193 epilepsy genes by focused exome sequencing revealed a novel heterozygous variant c.46G > C (p.Val16Leu; NM_001958.3) in EEF1A2. The variant was not detected in either parent, confirming its de novo origin. No additional variants that explain the patient's phenotypes were found by subsequent whole exome analysis. Copy number analysis of the exome data and exon-level microarray excluded a deletion in the other allele of EEF1A2. We present the first patient with a heterozygous pathogenic EEF1A2 variant who had dilated cardiomyopathy as well as neurodevelopmental phenotypes, suggesting that this cardiac phenotype may be associated with the autosomal dominant form of the EEF1A2-related disorder.

EEF1A2 triggers stronger ERK mediated metastatic program in ER negative breast cancer cells than in ER positive cells

AIMS

Ever since EEF1A2's identification as a putative oncogene in breast cancer, it has stimulated curiosity due to its contrasting role in predicting the prognostic values in breast cancer patients. Contradicting reports suggest it to be playing a pro-survival as well as a negative role in the survival of patients. This prompted us to find the association of this protein with molecular subtypes in breast cancer and its effect on EMT in representative cell lines.

MAIN METHODS

Data-mining was carried out to ascertain the correlation of EEF1A2 with molecular subtypes in breast cancer patients. Scratch wound healing and transwell invasion assays were carried out to assess its role in migration and invasion. Western blot, qRT-PCR, and ELISA were carried out to determine key signalling pathways, cytokines, and EMT factors responsible for the observed phenotype.

KEY FINDINGS

EEF1A2 was associated with ER receptor positivity in breast cancer and was involved in its transcriptional regulation. It induced a robust metastatic program in MDA-MB-231 (a triple-negative cell line), and induced significant changes in its invasive and migratory properties via activation of the ERK pathway. This was not the case in MCF7 which is an ER-positive cell line.

SIGNIFICANCE

We highlight the specific tendency of EEF1A2 to enhance invasive properties of cell lines in particular molecular subtype only. This sheds light on its selective role in regulating oncogenic processes in breast cancer and could explain its contradicting association with good survival, despite being an oncogene in a certain cohort of breast cancer patients.

Damaging de novo missense variants in EEF1A2 lead to a developmental and degenerative epileptic-dyskinetic encephalopathy

Heterozygous de novo variants in the eukaryotic elongation factor EEF1A2 have previously been described in association with intellectual disability and epilepsy but never functionally validated. Here we report 14 new individuals with heterozygous EEF1A2 variants. We functionally validate multiple variants as protein-damaging using heterologous expression and complementation analysis. Our findings allow us to confirm multiple variants as pathogenic and broaden the phenotypic spectrum to include dystonia/choreoathetosis, and in some cases a degenerative course with cerebral and cerebellar atrophy. Pathogenic variants appear to act via a haploinsufficiency mechanism, disrupting both the protein synthesis and integrated stress response functions of EEF1A2. Our studies provide evidence that EEF1A2 is highly intolerant to variation and that de novo pathogenic variants lead to an epileptic-dyskinetic encephalopathy with both neurodevelopmental and neurodegenerative features. Developmental features may be driven by impaired synaptic protein synthesis during early brain development while progressive symptoms may be linked to an impaired ability to handle cytotoxic stressors.

EEF1A2 mutations in epileptic encephalopathy/intellectual disability: Understanding the potential mechanism of phenotypic variation

EEF1A2 encodes protein elongation factor 1-alpha 2, which is involved in Guanosine triphosphate (GTP)-dependent binding of aminoacyl-transfer RNA (tRNA) to the A-site of ribosomes during protein biosynthesis and is highly expressed in the central nervous system. De novo mutations in EEF1A2 have been identified in patients with extensive neurological deficits, including intractable epilepsy, globe developmental delay, and severe intellectual disability. However, the mechanism underlying phenotype variation is unknown. Using next-generation sequencing, we identified a novel and a recurrent de novo mutation, c.294C>A; p.(Phe98Leu) and c.208G>A; p.(Gly70Ser), in patients with Lennox-Gastaut syndrome. The further systematic analysis revealed that all EEF1A2 mutations were associated with epilepsy and intellectual disability, suggesting its critical role in neurodevelopment. Missense mutations with severe molecular alteration in the t-RNA binding sites or GTP hydrolysis domain were associated with early-onset severe epilepsy, indicating that the clinical expression was potentially determined by the location of mutations and alteration of molecular effects. This study highlights the potential genotype-phenotype relationship in EEF1A2 and facilitates the evaluation of the pathogenicity of EEF1A2 mutations in clinical practice.

Expression pattern of EEF1A2 in brain tumors: Histological analysis and functional role as a promoter of EMT

AIMS

Glioblastomas are highly aggressive brain tumors with a very poor survival rate. EEF1A2, the proto-oncogenic isoform of the EEF1A translation factor family, has been found to be overexpressed and promoting tumorigenesis in multiple cancers. Interestingly, recent studies reported reduced expression of this protein in brain tumors, drawing our attention to find the functional role and mechanism of this protein in brain tumor progression.

MAIN METHODS

Using representative cell line as models, the role of EEF1A2 in cell proliferation, migration and invasion were assessed using MTS assay, scratch wound-healing assay, transwell migration and invasion assay, respectively. Activation of key signaling pathways was assessed using western blots and real-time PCR. Finally, using immunohistochemistry we checked the protein levels of EEF1A2 in CNS tumors.

KEY FINDINGS

EEF1A2 was found to increase the proliferative, migratory and invasive properties of cell lines of both glial and neuronal origin. PI3K activation directly correlated with EEF1A2 levels. Protein levels of key EMT markers viz. Twist, Snail, and Slug were increased upon ectopic EEF1A2 expression. Furthermore, EEF1A2 was found to affect the expression levels of key inflammatory cytokines, growth factors and matrix metalloproteases. IHC analysis showed that EEF1A2 is upregulated in tumor tissues compared to normal tissue.

SIGNIFICANCE

EEF1A2 acts as an oncogene in both neuronal and glial cells and triggers an EMT program via PI3K pathway. However, it shows enhanced expression in neuronal cells of the brain than the glial cells, which could explain the previously reported anomaly.

Whole exome sequencing reveals a de novo missense variant in EEF1A2 in a Rett syndrome-like patient

Using whole exome sequencing, we found a pathogenic variant in the EEF1A2 gene in a patient with a Rett syndrome-like (RTT-like) phenotype, further confirming the association between EEF1A2 and Rett syndrome RTT and RTT-like phenotypes.

The role of translation elongation factor eEF1 subunits in neurodevelopmental disorders

The multi-subunit eEF1 complex plays a crucial role in de novo protein synthesis. The central functional component of the complex is eEF1A, which occurs as two independently encoded variants with reciprocal expression patterns: whilst eEF1A1 is widely expressed, eEF1A2 is found only in neurons and muscle. Heterozygous mutations in the gene encoding eEF1A2, EEF1A2, have recently been shown to cause epilepsy, autism, and intellectual disability. The remaining subunits of the eEF1 complex, eEF1Bα, eEF1Bδ, eEF1Bγ, and valyl-tRNA synthetase (VARS), together form the GTP exchange factor for eEF1A and are ubiquitously expressed, in keeping with their housekeeping role. However, mutations in the genes encoding these subunits EEF1B2 (eEF1Bα), EEF1D (eEF1Bδ), and VARS (valyl-tRNA synthetase) have also now been identified as causes of neurodevelopmental disorders. In this review, we describe the mutations identified so far in comparison with the degree of normal variation in each gene, and the predicted consequences of the mutations on the functions of the proteins and their isoforms. We discuss the likely effects of the mutations in the context of the role of protein synthesis in neuronal development.

The EEF1A2 gene expression as risk predictor in localized prostate cancer

Background

Besides clinical stage and Gleason score, risk-stratification of prostate cancer in the pretherapeutic setting mainly relies on the serum PSA level. Yet, this is associated with many uncertainties. With regard to therapy decision-making, additional markers are needed to allow an exact risk prediction. Eukaryotic translation elongation factor 1 alpha 2 (EEF1A2) was previously suggested as driver of tumor progression and potential biomarker. In the present study its functional and prognostic relevance in prostate cancer was investigated.

Methods

EEF1A2 expression was analyzed in two cohorts of patients (n = 40 and n = 59) with localized PCa. Additionally data from two large expression dataset (MSKCC, Cell, 2010 with n = 131 localized, n = 19 metastatic PCa and TCGA provisional data, n = 499) of PCa patients were reanalyzed. The expression of EEF1A2 was correlated with histopathology features and biochemical recurrence (BCR). To evaluate the influence of EEF1A2 on proliferation and migration of metastatic PC3 cells, siRNA interference was used. Statistical significance was tested with t-test, Mann-Whitney-test, Pearson correlation and log-rank test.

Results

qRT-PCR revealed EEF1A2 to be significantly overexpressed in PCa tissue, with an increase according to tumor stage in one cohort (p = 0.0443). In silico analyses in the MSKCC cohort confirmed the overexpression of EEF1A2 in localized PCa with high Gleason score (p = 0.0142) and in metastatic lesions (p = 0.0038). Patients with EEF1A2 overexpression had a significantly shorter BCR-free survival (p = 0.0028). EEF1A2 expression was not correlated with serum PSA levels. Similar results were seen in the TCGA cohort, where EEF1A2 overexpression only occurred in tumors with Gleason 7 or higher. Patients with elevated EEF1A2 expression had a significantly shorter BCR-free survival (p = 0.043). EEF1A2 knockdown significantly impaired the migration, but not the proliferation of metastatic PC3 cells.

Conclusion

The overexpression of EEF1A2 is a frequent event in localized PCa and is associated with histopathology features and a shorter biochemical recurrence-free survival. Due to its independence from serum PSA levels, EEF1A2 could serve as valuable biomarker in risk-stratification of localized PCa.

Efficient and versatile CRISPR engineering of human neurons in culture to model neurological disorders

The recent identification of multiple new genetic causes of neurological disorders highlights the need for model systems that give experimental access to the underlying biology. In particular, the ability to couple disease-causing mutations with human neuronal differentiation systems would be beneficial. Gene targeting is a well-known approach for dissecting gene function, but low rates of homologous recombination in somatic cells (including neuronal cells) have traditionally impeded the development of robust cellular models of neurological disorders. Recently, however, CRISPR/Cas9 gene editing technologies have expanded the number of systems within which gene targeting is possible. Here we adopt as a model system LUHMES cells, a commercially available diploid human female mesencephalic cell line that differentiates into homogeneous mature neurons in 1-2 weeks. We describe optimised methods for transfection and selection of neuronal progenitor cells carrying targeted genomic alterations using CRISPR/Cas9 technology. By targeting the endogenous X-linked MECP2 locus, we introduced four independent missense mutations that cause the autism spectrum disorder Rett syndrome and observed the desired genetic structure in 3-26% of selected clones, including gene targeting of the inactive X chromosome. Similar efficiencies were achieved by introducing neurodevelopmental disorder-causing mutations at the autosomal EEF1A2 locus on chromosome 20. Our results indicate that efficiency of genetic "knock-in" is determined by the location of the mutation within the donor DNA molecule. Furthermore, we successfully introduced an mCherry tag at the MECP2 locus to yield a fusion protein, demonstrating that larger insertions are also straightforward in this system. We suggest that our optimised methods for altering the genome of LUHMES cells make them an attractive model for the study of neurogenetic disorders.

Two cases of early-onset myoclonic seizures with continuous parietal delta activity caused by EEF1A2 mutations

BACKGROUND

Mutations in the elongation factor 1 alpha 2 (EEF1A2) gene have recently been shown to cause severe intellectual disability with early-onset epilepsy. The specific manifestations of mutations in this gene remain unknown.

CASE REPORT

We report two cases of severe intellectual disability accompanied by early-onset epilepsy with continuous delta activity evident on electroencephalography. Both cases presented with developmental delay and repetitive myoclonic seizures in early infancy. Both cases showed continuous high-voltage delta activity over both parietal areas when awake, as revealed by interictal electroencephalograms. After the emergence of continuous delta activity, development stagnated. One case showed some development after relief of the seizures and epileptic activity, but drug resistant seizures recurred, and the development again became stagnant. In both cases, a de novo recurrent heterozygous mutation in EEF1A2 [c.364G>A (p.E122K)] was identified by whole-exome sequencing.

CONCLUSION

This report provides clinical data on epileptic encephalopathy in patients with EEF1A2 mutation. Continuous high-voltage delta activity seen over both parietal areas may be a unique manifestation of EEF1A2 mutation. Epileptic activity may aggravate the effect of the mutation on brain development.

Novel de novo EEF1A2 missense mutations causing epilepsy and intellectual disability

BACKGROUND

Exome sequencing has led to the discovery of mutations in novel causative genes for epilepsy. One such gene is EEF1A2, encoding a neuromuscular specific translation elongation factor, which has been found to be mutated de novo in five cases of severe epilepsy. We now report on a further seven cases, each with a different mutation, of which five are newly described.

METHODS

New cases were identified and sequenced through the Deciphering Developmental Disabilities project, via direct contact with neurologists or geneticists, or recruited via our website.

RESULTS

All the mutations cause epilepsy and intellectual disability, but with a much wider range of severity than previously identified. All new cases share specific subtle facial dysmorphic features. Each mutation occurs at an evolutionarily highly conserved amino acid position indicating strong structural or functional selective pressure.

CONCLUSIONS

EEF1A2 should be considered as a causative gene not only in cases of epileptic encephalopathy but also in children with less severe epilepsy and intellectual disability. The emergence of a possible discernible phenotype, a broad nasal bridge, tented upper lip, everted lower lip and downturned corners of the mouth may help in identifying patients with mutations in EEF1A2.

Clinicopathologic significance of expression of EEF1A2 and GRB2 in pancreatic adenocarcinoma

AIM: To investigate the expression of eukaryotic elongation factor 1A2 (EEF1A2) and growth factor receptor-bound 2 (GRB2) in pancreatic adenocarcinoma (PA) and to analyze their clinicopathologic significance.

METHODS: Expression of EEF1A2 and GRB2 was examined by immunohistochemistry in 97 PA specimens and surrounding pancreatic tissues.

RESULTS: EEF1A2 expression was absent in normal pancreatic tissue. In contrast, EEF1A2 showed positive immunoreactivity in 77.8% (76/97) of PA cases. The increased eEF1A2 expression was significantly associated with the presence of nodal metastasis (χ² = 4.28, P = 0.039) and perineural invasion (χ² = 4.11, P = 0.043). The expression rate of GRB2 in 97 PA specimens and surrounding pancreatic tissues were 82.5% (80/97) and 30.2% (31/97), respectively. The expression level of GRB2 in PA was significantly higher than that in surrounding pancreatic tissues (χ² = 48.5, P < 0.001). The positive rate of GRB2 expression was significantly correlated with lymph node metastasis (χ² = 4.63, P = 0.031). There was a positive expression between the expression of EEF1A2 and that of GRB2 in PA (r_s = 0.451, P < 0.001).

CONCLUSION: The expression of GRB2 and EEF1A2 is closely correlated with the biological behavior of PA. The expression of GRB2 is significantly correlated with that of EEF1A2.

De novo EEF1A2 mutations in patients with characteristic facial features, intellectual disability, autistic behaviors and epilepsy

Eukaryotic elongation factor 1, alpha-2 (eEF1A2) protein is involved in protein synthesis, suppression of apoptosis, and regulation of actin function and cytoskeletal structure. EEF1A2 gene is highly expressed in the central nervous system and Eef1a2 knockout mice show the neuronal degeneration. Until now, only one missense mutation (c.208G > A, p.Gly70Ser) in EEF1A2 has been reported in two independent patients with neurological disease. In this report, we described two patients with de novo mutations (c.754G > C, p.Asp252His and c.364G > A, p.Glu122Lys) in EEF1A2 found by whole-exome sequencing. Common clinical features are shared by all four individuals: severe intellectual disability, autistic behavior, absent speech, neonatal hypotonia, epilepsy and progressive microcephaly. Furthermore, the two patients share the similar characteristic facial features including a depressed nasal bridge, tented upper lip, everted lower lip and downturned corners of the mouth. These data strongly indicate that a new recognizable disorder is caused by EEF1A2 mutations.