Frameshift Variant in ARID2 in a Chilean Individual with Coffin-Siris Syndrome Phenotype.

Coffin-Siris syndrome (CSS) is one of the several causes of intellectual disability (ID) and, since its first description, has posed diagnostic challenges given its variability and phenotypic overlap with other alterations of chromatin-remodeling-associated syndromes. It is genetically heterogeneous, and causative mutations are detected in less than 70% of cases. The different subtypes of the syndrome described to date are caused by mutations in genes that encode subunits of the SWI/SNF chromatin-remodeling complex, which plays an essential role in the regulation of gene expression during embryogenesis. Whole exome sequencing (WES) has allowed the identification of pathogenic mutations in these genes, including ARID2 . ARID2 is one of the primary components of the SWI/SNF complex and has been associated with ID and phenotypes similar to CSS for the first time in 2015. Fifteen published case reports have identified loss-of-function mutations, suggesting that the underlying pathogenic disease mechanism is haploinsufficiency of ARID2 . We herein presented the case of an 8-year-old Chilean girl with clinical suspicion of CSS, in whom a novel frameshift variant in ARID2 was identified by WES. She was the first reported case in Latin America to our knowledge and her phenotype displays the main clinical features suggestive of CSS described in other patients with ARID2 variants. However, she did not present behavioral abnormalities, a characteristic frequently reported in the majority of patients with ARID2 variants, and also had some features, such as sparse scalp hair, which is frequently reported as a manifestation of CSS, but is uncommon in this new group of patients.

ARID2, a rare cause of Coffin-Siris syndrome: A novel microdeletion at 12q12q13.11 causing severe short stature and literature review.

Coffin-Siris syndrome (CSS) 6 is caused by heterozygous pathogenic variants in the AT-rich interaction domain 2 (ARID2) gene on 12q12. Currently, only 26 cases with both detailed clinical and genetic information have been documented in the literature. Microdeletions of the entire ARID2 gene are rare. In this study, we report a 5-year-7-month-old Chinese female who underwent whole-exome sequencing to discover that she had a de novo 1.563 Mb heterozygous copy number loss at 12q12q13.11, involving an entire deletion of ARID2. The female had severe short stature with obvious dysmorphic facial features, global developmental delay and hypoplastic fingers and toes. Her growth hormone level was normal, with reduced IGF-1 and increased CA19-9 levels. After a review of the 27 patients with ARID2 deficiency, a significant positive correlation was observed between age and height standard deviation score (SDS) (r = 0.71, p = 0.0002), suggesting a possibility of growth catch-up. This study expands the genetic and phenotypic spectrum of CCS6 and provides a decision-making reference for growth hormone therapy.

Coffin-Siris Syndrome: Case Series of Three Patients and a Novel ARID2 Variant.

Coffin-Siris syndrome (CSS) is a rare congenital disorder characterized by coarse facial features, intellectual disability or developmental delay, and aplasia or hypoplasia of the tips of the fifth finger and/or toes. Mutations in genes affecting the switch/sucrose non-fermenting ATP-dependent chromatin remodeling complex are reported to cause CSS. Here, we describe three CSS patients. Two girls aged 3 and 2 years old presented with global developmental delay, poor growth, and a dysmorphic face. Whole-exome sequencing (WES) was performed and they were diagnosed with CSS due to heterozygous frameshift variants (c.3443_3444del, p.Lys1148ArgfsTer9 and c.2869_2890del, p.Pro957CysfsTer20) in ARID1B A 2-year-old girl presented with gross motor delay and dysmorphic face. She was diagnosed with CSS due to a novel heterozygous frameshift variant (c.4942_4943del: p.Gln1648GlyfsTer8) in ARID2.

SIS3 Alleviates Cisplatin-Induced Acute Kidney Injury by Regulating the LncRNA Arid2-IR-Transferrin Receptor Pathway.

INTRODUCTION: TGF-ß/Smad3 may be involved in the pathogenesis of acute kidney injury (AKI), but its functional role and mechanism of action in cisplatin-induced AKI are unclear. Here, we established a cisplatin-induced AKI mouse model to demonstrate that Smad3 may have roles in cisplatin nephropathy because of its potential effects on tubular epithelial cell (TEC) death and regeneration. METHODS: Using a cisplatin-induced AKI model, the expression levels of lncRNA Arid2-IR were measured by qRT-PCR and the location detected by FISH. Transfected with overexpression of lncRNA Arid2-IR by lentiviral vector in TECs, and the expression of cleaved caspase 3, Bax, Bcl-2, PCNA, p21, p27, transferrin receptor (TFRC), FTH, and FTL were measured by Western blot. Protein molecules bound to lncRNA Arid2-IR were identified by RIP, RNA pull-down assay, mass spectrometry. RESULTS: LncRNA Arid2-IR was significantly downregulated in vivo and in vitro. SIS3 decreased cell apoptosis and promoted cell regeneration by upregulating lncRNA Arid2-IR expression. LncRNA Arid2-IR regulated the cell cycle by decreasing expression of the cyclin-dependent kinase inhibitors p21 and p27. Finally, lncRNA Arid2-IR interacted with the TFRC, and overexpression of lncRNA Arid2-IR increased TFRC expression and decreased FTH and FTL. CONCLUSION: Smad3 regulated lncRNA Arid2-IR via TFRC, thereby regulating the cell cycle, protecting against cell apoptosis, and promoting cell regeneration.

Arid2-IR downregulates miR-132-3p through methylation to promote LPS-induced ALI in pneumonia.

OBJECTIVE: Arid2-IR is a long non-coding RNA (lncRNA) that promotes renal injury, while its role in lipopolysaccharides (LPS)-induced acute lung injury (ALI) is unknown. Our preliminary sequencing analysis revealed an inverse correlation of Arid2-IR and miR-132-3p, which is known to suppress LPS-induced ALI. Therefore, Arid2-IR and miR-132-3p may interact with each other to participate in LPS-induced ALI in pneumonia. This study aimed to investigate the interaction between Arid2-IR and miR-132-3p in ALI induced by pneumonia. MATERIALS AND METHODS: Plasma samples were obtained from patients with pneumonia (n = 98) and healthy controls (n = 98) to detect the expression of circulating Arid2-IR and miR-132-3p. The correlation between them was analyzed using Pearson's correlation coefficient. The crosstalk between them in human bronchial epithelial cells (HBEpC) was analyzed through overexpression assay. MSP was applied to determine the methylation of the miR-132-3p gene. Cell viability was evaluated by 2,5-diphenyl-2H-tetrazolium bromide assay. RESULTS: Arid2-IR was highly upregulated in pneumonia group, while the expression levels of miR-132-3p decreased in pneumonia group compared to that in the controls. Arid2-IR and miR-132-3p were inversely correlated across patient samples. Overexpression of Arid2-IR decreased the expression levels of miR-132-3p in HBEpCs and increased the methylation of miR-132-3p gene. Arid2-IR suppressed the role of miR-132-3p in increasing the viability of HBEpCs induced by LPS. DISCUSSION AND CONCLUSION: Arid2-IR is upregulated in pneumonia and may downregulate miR-132-3p by increasing its methylation to decrease cell viability, thereby promoting LPS-induced ALI in pneumonia.

ARID2, a Rare Cause of Coffin-Siris Syndrome: A Clinical Description of Two Cases.

Background: Coffin-Siris syndrome (CSS) is a multiple congenital anomaly syndrome characterized by coarse facial features, sparse scalp hair, hypertrichosis, and hypo/aplastic digital nails and phalanges. Mutations in the BAF (SWI/SNF)-complex subunits (SMARCE1, SMARCB1, SMARCA4, SMARCA2, ARID1B, and ARID1A) have been shown to cause CSS. People diagnosed with BAF pathway related diseases are increasing, and ARID2 (NM_152641.4) is the least common of these genes. Mutations in the ARID2 gene is the cause for Coffin-Siris syndrome 6 (CSS6). By now only 16 individuals with CSS have been reported to have pathogenic variants in ARID2. Case Presentation: In this article, we introduced two individuals with clinical features consistent with CSS6 (Coffin-Siris syndrome 6). This article increases the number of reported cases, provides better phenotypic information for this rare syndrome, and allows everyone to better understand the disease. Conclusion: Our observations indicate that ARID2 mutations could have variable phenotypes, even in patients from the same family.

Integrative RNA profiling of TBEV-infected neurons and astrocytes reveals potential pathogenic effectors.

Tick-borne encephalitis virus (TBEV), the most medically relevant tick-transmitted flavivirus in Eurasia, targets the host central nervous system and frequently causes severe encephalitis. The severity of TBEV-induced neuropathogenesis is highly cell-type specific and the exact mechanism responsible for such differences has not been fully described yet. Thus, we performed a comprehensive analysis of alterations in host poly-(A)/miRNA/lncRNA expression upon TBEV infection in vitro in human primary neurons (high cytopathic effect) and astrocytes (low cytopathic effect). Infection with severe but not mild TBEV strain resulted in a high neuronal death rate. In comparison, infection with either of TBEV strains in human astrocytes did not. Differential expression and splicing analyses with an in silico prediction of miRNA/mRNA/lncRNA/vd-sRNA networks found significant changes in inflammatory and immune response pathways, nervous system development and regulation of mitosis in TBEV Hypr-infected neurons. Candidate mechanisms responsible for the aforementioned phenomena include specific regulation of host mRNA levels via differentially expressed miRNAs/lncRNAs or vd-sRNAs mimicking endogenous miRNAs and virus-driven modulation of host pre-mRNA splicing. We suggest that these factors are responsible for the observed differences in the virulence manifestation of both TBEV strains in different cell lines. This work brings the first complex overview of alterations in the transcriptome of human astrocytes and neurons during the infection by two TBEV strains of different virulence. The resulting data could serve as a starting point for further studies dealing with the mechanism of TBEV-host interactions and the related processes of TBEV pathogenesis.

Altered BAF occupancy and transcription factor dynamics in PBAF-deficient melanoma.

ARID2 is the most recurrently mutated SWI/SNF complex member in melanoma; however, its tumor-suppressive mechanisms in the context of the chromatin landscape remain to be elucidated. Here, we model ARID2 deficiency in melanoma cells, which results in defective PBAF complex assembly with a concomitant genomic redistribution of the BAF complex. Upon ARID2 depletion, a subset of PBAF and shared BAF-PBAF-occupied regions displays diminished chromatin accessibility and associated gene expression, while BAF-occupied enhancers gain chromatin accessibility and expression of genes linked to the process of invasion. As a function of altered accessibility, the genomic occupancy of melanoma-relevant transcription factors is affected and significantly correlates with the observed transcriptional changes. We further demonstrate that ARID2-deficient cells acquire the ability to colonize distal organs in multiple animal models. Taken together, our results reveal a role for ARID2 in mediating BAF and PBAF subcomplex chromatin dynamics with consequences for melanoma metastasis.

Concomitant novel ALK-SSH2, EML4-ALK and ARID2-ALK, EML4-ALK double-fusion variants and confer sensitivity to crizotinib in two lung adenocarcinoma patients, respectively.

INTRODUCTION: Anaplastic lymphoma kinase (ALK) gene rearrangements, have been identified in approximately 2-7% of patients with lung adenocarcinoma (LUAD). However, co-occurrence of double ALK fusions in one patient was rare. Herein, we reported two Chinese female LUAD patients with confirmed double ALK fusion variants by next generation sequencing. CASE PRESENTATION: Case 1, a 38-year-old female was diagnosed as peripheral LUAD in left upper lobe with synchronous multiple intrapulmonary metastases (pT2N0M1b, stage IVa). And case 2, a 58-year-old female had left lower lobe primary LUAD and synchronous multiple lung metastases (pT4N2M1b, stage IVa). In both patients, tumor cells displayed strong expression of ALK protein. Genetic profiling by next generation sequencing showed both patients concurrently harbored two types of ALK rearrangements. Case 1 had an unreported ALK-SSH2/EML4-ALK double fusions, and case 2 had an another novel ARID2-ALK/EML4-ALK double fusions. Both of these patients responded to ALK inhibitor crizotinib. CONCLUSIONS: Our study reported two novel ALK fusion partners never reported, which expands the knowledge of ALK fusion spectrum and provides insight into therapeutic options for patients with double ALK fusions.

Targeting HSPA1A in ARID2-deficient lung adenocarcinoma.

Somatic mutations of the chromatin remodeling gene ARID2 are observed in ∼7% of human lung adenocarcinomas (LUADs). However, the role of ARID2 in the pathogenesis of LUADs remains largely unknown. Here we find that ARID2 expression is decreased during the malignant progression of both human and mice LUADs. Using two KrasG12D -based genetically engineered murine models, we demonstrate that ARID2 knockout significantly promotes lung cancer malignant progression and shortens overall survival. Consistently, ARID2 knockdown significantly promotes cell proliferation in human and mice lung cancer cells. Through integrative analyses of ChIP-Seq and RNA-Seq data, we find that Hspa1a is up-regulated by Arid2 loss. Knockdown of Hspa1a specifically inhibits malignant progression of Arid2-deficient but not Arid2-wt lung cancers in both cell lines as well as animal models. Treatment with an HSPA1A inhibitor could significantly inhibit the malignant progression of lung cancer with ARID2 deficiency. Together, our findings establish ARID2 as an important tumor suppressor in LUADs with novel mechanistic insights, and further identify HSPA1A as a potential therapeutic target in ARID2-deficient LUADs.

CREB1 acts via the miR­922/ARID2 axis to enhance malignant behavior of liver cancer cells.

There is little information on the role of microRNA (miR)­922 in the malignant behavior of liver cancer. The present study investigated the regulation of miR­922 expression levels by cAMP response element binding protein 1 (CREB1) in liver cancer tissue, its role in regulating malignant behavior and its potential targets in liver cancer. miR­922 expression in liver cancer cells and tissue was determined by reverse transcription­quantitative PCR. The binding of CREB1 to the promoter region of mir­922 was tested by chromatin immunoprecipitation­PCR. The predicted AT­rich interactive domain 2 (ARID2) and fidgetin, microtubule severing factor targets of miR­922 were characterized by dual luciferase reporter assay. The effects of altered ARID2 expression levels on miR­922­enhanced malignant behavior of liver cancer cells were tested. CREB1 bound to the promoter region of miR­922. Elevated miR­922 transcripts were inversely associated with ARID2 expression in liver cancer tissue and cells. miR­922 inhibited ARID2­regulated luciferase expression and was present in the miR/argonaute RISC catalytic component 2 complex. ARID2 significantly decreased malignant behavior of liver cancer MHCC97L cells. Similarly, ARID2 over­expression inhibited growth of xenograft liver cancer tumors and decreased miR­922, Bcl­2, proliferating cell nuclear antigen, cyclin D1, MMP3 and MMP9 expression and serum VEGF and TNF­α levels, but enhanced Bax expression levels in tumors. ARID2 over­expression abrogated malignant behavior promoted by miR­922 over­expression and enhanced miR­922­decreased malignant behavior of liver cancer cells. CREB induced miR­922 transcription, which targeted ARID2 to enhance malignant behavior of liver cancer cells, indicating that the CREB1/miR­922/ARID2 axis may be a potential target for liver cancer treatment.

Arid2-IR promotes NF-κB-mediated renal inflammation by targeting NLRC5 transcription.

Increasing evidence shows that long non-coding RNAs (lncRNAs) play an important role in a variety of disorders including kidney diseases. It is well recognized that inflammation is the initial step of kidney injury and is largely mediated by nuclear factor Kappa B (NF-κB) signaling. We had previously identified lncRNA-Arid2-IR is an inflammatory lncRNA associated with NF-κB-mediated renal injury. In this study, we examined the regulatory mechanism through which Arid2-IR activates NF-κB signaling. We found that Arid2-IR was differentially expressed in response to various kidney injuries and was induced by transforming growth factor beta 1(TGF-ß1). Using RNA sequencing and luciferase assays, we found that Arid2-IR regulated the activity of NF-κB signal via NLRC5-dependent mechanism. Arid2-IR masked the promoter motifs of NLRC5 to inhibit its transcription. In addition, during inflammatory response, Filamin A (Flna) was increased and functioned to trap Arid2-IR in cytoplasm, thereby preventing its nuclear translocation and inhibition of NLRC5 transcription. Thus, lncRNA Arid2-IR mediates NF-κB-driven renal inflammation via a NLRC5-dependent mechanism and targeting Arid2-IR may be a novel therapeutic strategy for inflammatory diseases in general.

ARID2 Chromatin Remodeler in Hepatocellular Carcinoma.

Chromatin remodelers are found highly mutated in cancer including hepatocellular carcinoma. These mutations frequently occur in ARID (AT-rich Interactive Domain) genes, encoding subunits of the ATP-dependent SWI/SNF remodelers. The increasingly prevalent complexity that surrounds the functions and specificities of the highly modular BAF (BG1/BRM-associated factors) and PBAF (polybromo-associated BAF) complexes, including ARID1A/B or ARID2, is baffling. The involvement of the SWI/SNF complexes in diverse tissues and processes, and especially in the regulation of gene expression, multiplies the specific outcomes of specific gene alterations. A better understanding of the molecular consequences of specific mutations impairing chromatin remodelers is needed. In this review, we summarize what we know about the tumor-modulating properties of ARID2 in hepatocellular carcinoma.

Long non-coding RNA Arid2-IR affects advanced glycation end products-induced human retinal endothelial cell injury by binding to Smad3.

PURPOSE: Long non-coding RNAs (lncRNAs) have been reported to play significant roles in the pathogenesis of diabetic retinopathy (DR). The aim of the present study was to investigate the role of lncRNA Arid2-IR in advanced glycation end product (AGE)-induced human retinal endothelial cells (HRECs) injury. MATERIALS AND METHODS: Cell viability was determined by Cell Counting Kit-8 assay following induction with AGEs. The expression of Arid2-IR and Smad3 was detected by reverse transcription-quantitative PCR or western blotting. A luciferase reporter assay was conducted to determine the interaction between Arid2-IR and Smad3. The levels of inflammation-related and oxidative stress-related factors were evaluated by respective kits. The expression of extracellular matrix (ECM)-related and apoptosis-related proteins was detected by western blotting. Immunofluorescence assay was used to detect the level of vascular endothelial growth factor, and flow cytometry was applied to measure the levels of apoptosis. RESULTS: The results revealed that AGE treatment decreased HREC proliferation and upregulated the expression of Arid2-IR and Smad3. The luciferase assay indicated that Smad3 was able to bind to the promoter region sequence of Arid2-IR. Moreover, Arid2-IR silencing reduced inflammation, oxidative stress and ECM production induced by AGEs in HRECs, and Smad3 inhibition further reduced the levels of the aforementioned factors, while Smad3 overexpression exerted the opposite effect. Furthermore, apoptosis of HRECs induced by AGEs was decreased following Arid2-IR silencing, which was further reduced following treatment with Smad3 inhibitor, but was reversed after transfection with Smad3 pcDNA3.1. CONCLUSION: The findings demonstrated that Arid2-IR affects AGE-induced HREC injury by binding to Smad3.

Hepatic Infiltration with Malignant T-cells Manifesting as Impending Acute Liver Failure in Sezary Syndrome.

We describe a case of impending acute liver failure in a patient with Sézary syndrome (SS). The three-phase computed tomography (CT) of the liver showed neither mass nor hepatomegaly. Liver biopsy confirmed infiltration with malignant CD4+ clonal T-cells. Prompt administration of combination chemotherapy, consisting of gemcitabine, dexamethasone, and cisplatin (GDP), resulted in full recovery of liver function. To the best of our knowledge, this is the first report of liver failure from SS. Commercial next-generation sequencing panel identified 11 clinically relevant mutations. Interestingly, the identified ARID2 mutation, frequently observed in hepatocellular carcinoma, rarely occurs in hematologic malignancies. Further studies are necessary to elucidate the role of ARID2 mutations in the biological behavior of Sezary cells, such as a propensity to infiltrate liver parenchyma.

Patient with anomalous skin pigmentation expands the phenotype of ARID2 loss-of-function disorder, a SWI/SNF-related intellectual disability.

ARID2 loss-of-function is associated with a rare genetic disorder characterized in 14 reported patients to date. ARID2 encodes a member of the SWItch/sucrose non-fermentable chromatin remodeling complex. Other genes encoding subunits of this complex, such as ARID1A, ARID1B, and SMARCA2, are mutated in association with Coffin-Siris syndrome (CSS) and Nicolaides Baraitser syndrome (NCBRS) phenotypes. Previously reported ARID2 mutations manifested clinically with a CSS-like phenotype including intellectual disability, coarsened facial features, fifth toenail hypoplasia, and other recognizable dysmorphisms. However, heterogeneity exists between previously reported patients with some patients showing more overlapping features with NCBRS. Herein, we present a patient with a novel disease-causing ARID2 loss-of-function mutation. His clinical features included intellectual disability, coarse and dysmorphic facial features, toenail hypoplasia, ADHD, short stature, and delayed development consistent with prior reports. Our patient also presented with previously unreported clinical findings including ophthalmologic involvement, persistent fetal fingertip and toetip pads, and diffuse hyperpigmentary and hypopigmentary changes sparing his face, palms, and soles. The anomalous skin findings are particularly of interest given prior literature outlining the role of ARID2 in melanocyte homeostasis and melanoma. This clinical report and review of the literature is further affirming of the characteristic symptoms and expands the phenotype of this newly described and rare syndrome.

Extending the clinical and genetic spectrum of ARID2 related intellectual disability. A case series of 7 patients.

In the last 3 years de novo sequence variants in the ARID2 (AT-rich interaction domain 2) gene, a subunit of the SWI/SNF complex, have been linked to intellectual disabilities in 3 case reports including one which describes frameshift mutations in ARID2 in 2 patients with features resembling Coffin-Siris syndrome. Coffin-Siris syndrome (CSS) is a rare congenital syndrome characterized by intellectual deficit, coarse facial features and hypoplastic or absent fifth fingernails and/or toenails among other features. Mutations in a number of different genes encoding SWI/SNF chromatin remodelling complex proteins have been described but the underlying molecular cause remains unknown in approximately 40% of patients with CSS. Here we describe 7 unrelated individuals, 2 with deletions of the ARID2 region and 5 with de novo truncating mutations in the ARID2 gene. Similarities to CSS are evident. Although hypertrichosis and hypoplasia of the fifth finger nail and distal phalanx do not appear to be common in these patients, toenail hypoplasia and the presence of Wormian bones might support the involvement of ARID2.

MicroRNA-376c-3p Facilitates Human Hepatocellular Carcinoma Progression via Repressing AT-Rich Interaction Domain 2.

Hepatocellular carcinoma (HCC), accounting for approximately 90% of liver cancer, is the most lethal malignant tumors in the world. Large amount of evidence indicate that microRNAs (miRNAs) contribute to the tumorigenesis and progression of HCC. Among them, miR-376c-3p was recently identified as a tumor-related miRNA and is up-regulated in HBV-related HCC. But, the clinical significance of miR-376c-3p and its biological function in HCC progression are still unclear. Here, we confirmed that miR-376c-3p expression level in HCC was markedly higher than that in noncancerous tissues. Up-regulation of miR-376c-3p was detected in four different HCC cell lines. High miR-376c-3p expression correlated with poor prognostic features, such as large tumor size and venous infiltration. Follow-up data indicated that high miR-376c-3p level evidently correlated with poor clinical outcomes of HCC patients. Moreover, knockdown of miR-376c-3p repressed HCC cell growth, migration and invasion in vitro. miR-376c-3p overexpression facilitated these malignant behaviors of Bel-7402 cells. Mechanistically, miR-376c-3p posttranscriptionally repressed ARID2 expression by directly interacting with its 3'-UTR. Furthermore, an obvious negative correlation between miR-376c-3p and ARID2 mRNA expression in HCC tissues was confirmed. Notably, miR-376c-3p knockdown suppressed HCC growth and metastasis in nude mice. Gain-of-function experiments showed that ARID2 inhibited cell growth and mobility of Hep3B cells. Subsequently, ARID2 knockdown rescued miR-376c-3p silencing attenuated Hep3B cell proliferation and mobility. Our results suggest that miR-376c-3p exerts an oncogenic role in HCC progression.

Analysis of ARID2 Gene Mutation in Oral Squamous Cell Carcinoma

Background: The ARID2 gene, encoding a sub unit of the chromatin remodelling complex, has a possible tumour suppressor function and has been found to be frequently mutated in various tumours, including gingivo buccal oral squamous cell carcinomas. The present study was designed to analyse the presence of ARID2 gene mutations in the distinct genetic South Indian (Dravidian) population. Materials and Methods: Genomic DNA from thirty biopsy tissue samples of histopathologically confirmed cases of oral squamous cell carcinoma (OSCC) were subjected to PCR amplification with intronic primers encompassing exons 19 and 20 of ARID2. Subsequently, the PCR amplicons were purified and subjected to Sanger sequencing using forward primers for analysis of mutational status. Results: Our study yielded a 6% occurrence of mutations in the ARID2 gene among the thirty OSCC samples. Two samples showed a C(5174)A nonsense mutation whereby the "C" nucleotide was substituted with an "A" nucleotide at position 5174, resulting in the conversion of serine amino acid at codon 1725 to a premature STOP codon. Conclusion: Identification of ARID2 gene mutations in OSCCs in this distinct ethnic population reaffirms that aberrations in the chromatin remodelling complex could indeed also contribute to tumorigenesis, thus providing new insights for future research.