CTNNB1 Gene Mutations Research Articles

A Rare Case Of Desmoid Tumor In The Lower Mandibular Sector Of An Adolescent: Surgical Intervention And Outcomes

Introduction: Desmoid tumors are rare, benign neoplasms known for their locally aggressive behavior and high recurrence rates. They arise from fibroblasts and are characterized by their infiltrative growth, making surgical management challenging. This report presents a case of a desmoid tumor in the lower mandibular sector of a 16-year-old male, focusing on surgical intervention and molecular insights. Case Report: A 16-year-old male presented with a growing mass in the lower right mandible, causing pain and mobility of tooth 47. Imaging revealed an infiltrative lesion eroding the mandibular bone. Histopathological analysis confirmed a desmoid tumor with spindle-shaped fibroblasts and nuclear β-caténine expression. Molecular testing identified a CTNNB1 gene mutation, confirming the diagnosis. Discussion: Desmoid tumors, despite being benign, are challenging due to their aggressive local behavior. Surgical excision with clear margins is the primary treatment, as these tumors are resistant to chemotherapy and radiotherapy. This case highlights the importance of precise surgical planning and the role of β-caténine and CTNNB1 mutations in diagnosis and prognosis. Conclusion: Effective management of desmoid tumors in adolescents requires thorough surgical intervention and comprehensive diagnostic analysis. Long-term follow-up is crucial to monitor for recurrence. The molecular characteristics of the tumor, such as CTNNB1 mutations, play a significant role in guiding treatment and predicting outcomes.

Histogenetic insights and genetic landscape of fibromatosis-like undifferentiated gastric carcinoma: a focused study

BackgroundThe aim of this study was to elucidate the histogenesis and genetic underpinnings of fibromatosis-like undifferentiated gastric carcinoma (FLUGC), a rare pathological entity.MethodThrough a detailed analysis of seven cases, including histopathological evaluation, CTNNB1 gene mutation screening, human epidermal growth factor receptor 2 (HER2) protein level quantification, and HER2 gene amplification assessment to identify the pathological and molecular characteristics of FLUGC.ResultsOf the seven patients in this study, five were male and two were female (age: 39–73 years). Four patients presented with lesions in the gastric antrum and three had lesions in the lateral curvature of the stomach. Histopathologically, over 90% of the tumor consisted of aggressive fibromatosis-like tissue, including proliferating spindle fibroblasts and myofibroblasts and varying amounts of collagenous fibrous tissues. Undifferentiated cancer cells, accounting for less than 10%, were dispersed among the aggressive fibromatosis-like tissues. These cells were characterized by their small size and were relatively sparse without glandular ducts or nested mass-like structures. Immunophenotyping results showed positive expression of CKpan, CDX2, villin, and p53 in undifferentiated cancer cells; positive expression of vimentin in aggressive fibromatosis-like tissue; positive cytoplasmic expression of β-catenin; and focal cytoplasmic positive expression of smooth muscle actin (SMA). Genetic analysis did not reveal any mutations in the CTNNB1 gene test, nor was there amplification in the HER2 gene fluorescence in situ hybridization (FISH) test. Additionally, the Epstein-Barr encoding region (EBER) of in situ hybridization was negative; and the mismatch repair (MMR) protein was positive. Programmed cell death-1 (PD-1) was < 1–5%; programmed cell death ligand 1 (PD-L1): TPS = 1–4%, CPS = 3–8.ConclusionThe study highlights the significance of CTNNB1, HER2, EBER, and MMR as pivotal genetic markers in FLUGC, underscoring their relevance for diagnosis and clinical management. The rarity and distinct pathological features of FLUGC emphasize the importance of accurate diagnosis to prevent underdiagnosis or misdiagnosis and to raise awareness within the medical community.

Liquid biopsy multiomics enable clinical triage for early colorectal cancer diagnosis.

e15599 Background: Colorectal cancer (CRC) is the second most common cause of cancer death in the United State. Despite advancements in screening, diagnosis, and treatment, the disease remains a formidable public health issue. In 2023, approximately 153020 individuals were diagnosed with CRC and 52550 will die from the disease. In order to meet early diagnostic, we developed this multiomics assay to enable clinical triage for liquid biopsy screening. Methods: Xenonucleic acid (XNAs) are artificial genetic polymers that retain the Watson-Crick base-pairing capability and exhibit high chemical and biological stability. They can be employed as molecular clamps in RT-qPCR due to the stronger hybridizing/binding capability seen in XNA/DNA duplexes than DNA/DNA duplexes. We are developing an XNA-based multiplex RT-qPCR assay for APC, BRAF, CTNNB1, KRAS, NRAS, PIK3CA, SMAD4 and TP53 gene mutation panel and CRC 9 genes methylation panel combined with multiplex protein panel, called ColoscapeTM Plus. We enrolled in FIT positive subjects of both genders, aged 50-74, attending the CRC screening program, we tested 152 plasma samples, 75 health, 50 AA and 27 early CRC with this multiomics assay. Results: The assay results showed that its sensitivity was about 44% (95% CI: 0.302- 0.587) and specificity about 80% (95%CI: 0.689- 0.880) for advanced adenoma (AA). For CRC stage I and II, its sensitivity is about 63% and 78% with 80% specificity separately. Conclusions: The primary data has shown that this low cost and rapid turnaround time multiomics assay has a comparable sensitivity for early colorectal cancer diagnostic.

Assessments of TP53 and CTNNB1 gene hotspot mutations in circulating tumour DNA of hepatitis B virus-induced hepatocellular carcinoma.

Background: Hepatitis B virus (HBV) infection is one of the major causes of chronic liver disease, which progresses from chronic hepatitis B (CHB) to fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). Early detection and laboratory-based screening of hepatocellular carcinoma are still major challenges. This study was undertaken to determine whether the cancer hallmark gene signatures that are released into circulation as circulating tumour DNA (ctDNA) can be used as a liquid biopsy marker for screening, early detection, and prognosis of HCC. Methods: A total of 130 subjects, including HBV-HCC (n = 80), HBV-cirrhotic and non-cirrhotic (n = 35), and healthy (n = 15) controls, were evaluated for TP53 and beta-catenin (CTNNB1) gene hotspot mutations in ctDNA by Sanger-based cycle sequencing and droplet digital PCR (ddPCR) assays. Mutation detection frequency, percentage mutant fractions, and their association with tumour stage, mortality, and smoking habits were determined. Results: Sanger-based cycle sequencing was carried out for 32 HCC patients. Predict SNP Tools analysis indicated several pathogenic driver mutations in the ctDNA sequence, which include p.D228N, p.C229R, p.H233R, p.Y234D, p.S240T, p.G245S, and p.R249M for TP53 gene exon 7 and p.S33T for CTNNB1 gene exon 3. The TP53 c.746G>T (p.R249M) mutation was detected predominately (25% cases) by sequencing, but there was no dominant mutation at position c.747G>T (p.R249S) that was reported for HBV-HCC patients. A dual-probe ddPCR assay was developed to determine mutant and wild-type copy numbers of TP53 (p.R249M and p.R249S) and CTNNB1 (p.S45P) and their percentage mutant fraction in all 130 subjects. The TP53 R249M and CTNNB1 S45P mutations were detected in 31.25% and 26.25% of HCC patients, respectively, with a high mutant-to-wild-type fraction percentage (1.81% and 1.73%), which is significant as compared to cirrhotic and non-cirrhotic patients. Poor survival was observed in HCC patients with combined TP53 and CTNNB1 gene driver mutations. The TP53 R249M mutation was also significantly (p < 0.0001) associated with smoking habits (OR, 11.77; 95% CI, 3.219-36.20), but not the same for the TP53 R249S mutation. Conclusion: Screening of ctDNA TP53 and CTNNB1 gene mutations by ddPCR may be helpful for early detection and identifying the risk of HCC progression.

Craniopharyngioma-An update on metabolic and cognitive complications and new therapy.

Craniopharyngiomas (CPs) are rare primary brain epithelial tumors arising in the suprasellar region from remnants of Rathke's pouch. About 50% originate at the level of the third ventricle floor, including the hypothalamus (HT). CPs are characterized by a low proliferation rate and symptoms due to mass effect and local infiltration and are managed primarily with surgery and radiotherapy. Gross total removal of a CP will reduce the recurrence rate but increases the risk of HT damage. Today, subtotal resection is the goal and will reduce the risk of HT damage. There are two histological subtypes of CP-adamantinomatous (ACP) and papillary CP (PCP)-that differ in their genesis and age distribution. ACPs are driven by somatic mutations in CTNNB1 gene (encoding β-catenin), and PCPs frequently harbor somatic BRAF V600E mutations. There are also two phenotypes of outcome, the one with a rather good outcome without HT damage and the other with HT damage where recurrent operation with additional cranial radiotherapy results in HT obesity (HO), affecting psychosocial life and cognitive dysfunction. The group with HO suffers from metabolic syndrome, lower basal metabolic rate, and leptin and insulin resistances. There is currently no successful treatment for HO. The group with HT damage suffers from cognitive dysfunction with attention deficits, impaired episodic memory, and processing speed. Diffusion tensor imaging has shown significant microstructural white matter alteration in several areas important for cognition. Recently, complete or partial tumor response was shown to targeted therapy, with BRAF and Mekinist inhibitors for PCPs with BRAF V600E mutation.

Understanding Glomangiopericytoma: A Case Report of a Rare Sinonasal Tumor

Introduction: Glomangiopericytoma (GPC) is a benign neoplasm of the sinonasal tract that consists of spindle-shaped to ovoid cells with lobular or nodular growth patterns. GPCs are low-malignant tumors due to limited mitotic activity and atypia, making them less aggressive. The etiology of GPC remains unknown but is associated with factors like steroid use, past trauma, pregnancy, and hypertension. GPC is more common in women and is usually diagnosed in the sixth and seventh decades of life. Case Presentation: This article presents a case of a 47-year-old woman with a history of type-2 diabetes and nasal obstruction who was diagnosed with glomangiopericytoma (GPC), a rare sinonasal tumor. Computed tomography revealed a vascular mass, and complete surgical resection was achieved via a trans-nasal approach. The diagnosis was confirmed through positive β-catenin staining and negative S100p and STAT6 with a low Ki67 proliferation index. The patient experienced post-operative pain, anosmia, and ageusia, which were treated successfully. This case highlights the clinicopathologic characteristics, clinical and therapeutic aspects, surgical interventions, and differential diagnosis of GPC, a rare disease with limited reports. Conclusion: Glomangiopericytomas are benign sinonasal tumors often mistaken for other neoplasms. Diagnosis is challenging but possible through excision or biopsy with histopathological examination. Endoscopic surgery with follow-up is the recommended treatment, with recurrence occurring up to 12 years post-surgery. CTNNB1 gene mutations and β-catenin nuclear expression are recent diagnostic markers. GPC has a high survival rate and low metastasis, but patients should be closely monitored. This case report underscores the importance of comprehensive diagnosis and management for these rare tumors.

Desmoid-type fibromatosis of the mesentery: a clinicopatho-logical and genetic analysis of 9 cases.

Nine cases of mesenteric desmoid-type fibromatosis were diagnosed and treated in Taizhou Hospital, Wenzhou Medical University between January 2010 and May 2022, including 2 females and 7 males, aged 16 to 59 years. The lesions were in the mesentery of small intestine with 7 cases, ileocecal junction with 1 cases and transverse colon with 1 case. The tumors had an unclear boundary and no envelope, the section was solid, gray and tough. The mean maximum diameter was (10.7±8.5) cm (range 3.5-33.0 cm). Microscopically, fusiform fibroblasts and myofibroblasts were parallel, bunched or staggered, buried in a large amount of extracellular collagen. The cell morphology was relatively consistent, without obvious atypia, and mitosis was rare. Immunohistochemistry showed that the tumor cells were positive for vimentin (9/9), β-catenin (9/9), while smooth muscle actin (5/9) stains were focally positive. Ki-67 proliferation index was 1%-10%. Cytokeratin Pan, S-100, STAT6, CD117, DOG1, CD34, desmin and anaplastic lymphoma kinase stains were negative. Genetic analysis showed that there were 7 cases of c.121G>A(p.Thr41Ala) mutation of CTNNB1 gene, 1 case of c.121G>A(p.Thr41Ala) and 1 case of c.134C>T(p.Ser45Phe) double mutation, and 1 case of wild type. Tumors were surgically resected in all 9 cases. Eight cases had no recurrence or metastasis, 1 case had recurrence 6 months later, and no recurrence or metastasis after additional surgical resection.

Malignant transformation of fundic gland polyps in familial adenomatous polyposis

Sporadic fundic gland polyps (FGPs) are ubiquitous benign lesions with no potential for malignant transformation. Familial adenomatous polyposis (FAP) is associated with the development of FGPs that are morphologically identical to but genetically distinct from those seen in sporadic cases. The shared aetiology involves disruption of the WNT signalling pathway, however FAP associated cases are predominantly driven by germline APC gene mutations rather than the somatic CTNNB1 gene mutations prevalent in sporadic lesions.

Abstract PO010: Molecular characterization of pediatric hepatocellular carcinoma: genomic, methylomic and transcriptomic analysis

Abstract Background: The main pediatric liver tumors are hepatoblastoma (HB) and, to a lesser extent, pediatric hepatocellular carcinoma (HCC). HB appears at an early age (&amp;lt;3 years) while HCC is diagnosed mainly in older children (&amp;gt;8 years) or adolescents and it is usually associated to underlying metabolic diseases. HEM-NOS (Hepatocellular malignant neoplasm, not otherwise specified) is a recent entity with histopathological features of HB and HCC. Due to the rarity of the disease (&amp;lt;1 case per million children), the biology of HCC and their similarity with HB has been poorly explored. Aims: To molecularly characterize pediatric HCC at the genomic, transcriptomic and epigenomic level and to perform a comparative study with HB and HEM-NOS. Methodology: We performed a genomic (Cytoscan, ThermoFisher), epigenomic (EPIC/850k, Illumina) and transcriptomic (HTA 2.0 array, ThermoFisher) studies on 8 HCC and compared them with already published omics data of 31 HB, 2 HEM-NOS and 19 control non-tumor liver (NT) samples (Carrillo-Reixach et al, J Hepatol, 2020). The results obtained were validated in an independent series of 19 HCC, including 10 fibrolamellar HCC (FL-HCC), 56 HB, 7 HEM-NOS and 5 NTs using QUAlu and Nanostring techniques for assessing DNA methylation and gene expression, respectively. Results: We identified CTNNB1 gene mutations in 73%, 50% and 14% of HB, HEM-NOS and HCC, respectively. Contrarily, TERT mutations were only found in HEM-NOS and HCC tumors. FL-HCC had the DNAJB1:PRKACA fusion transcript and in one case without this fusion, a deletion in the PRKCA gene was identified. The genome of HCC and HEM-NOS had higher number of chromosomal losses than HB. Moreover, HBs and HEM-NOS showed a higher DNA hypomethylation than HCC whereas HCC was characterized by CpG island hypermethylation. Two imprinting regions were differently expressed in 14q32 (DLK1/DIO3) and 15q11.2 (SNORD115/116) in HB and HCC, respectively. Finally, we identified the SPINK1 gene (Serine peptidase inhibitor, kazal type 1) as an overexpressed gene in HCC that was strongly associated with prognosis of patients with liver cancer in both training (Log-Rank=0.008) and validation sets (Log-rank=0.028). Using XENA database, we found also that different SPINK1 expression was also associated with adult HCC prognosis (n=357, Log-rank=0.017). Conclusions: The characterization of HCC and its comparison with HB allowed us to identify potential diagnostic and prognostic markers that could help to improve the clinical management of childhood liver cancer. Citation Format: Juan Carrillo-Reixach, Álvaro del Río-Álvarez, Laura Royo, Montserrat Domingo-Sàbat, Rita Alaggio, Ronald de Krijger, Christian Vokuhl, Marta Garrido, Laura Guerra, Constantino Sábado, Francisco Hernández, Manuel López-Santamaría, Viera Bajčiová, Rudolf Maibach, Margaret Childs, Piotr Czauderna, Keith Wheatley, Roland Kappler, Stefano Cairo, Bruce Morland, Margarita Sala, Maria Rosa Sarrias, Carolina Armengol. Molecular characterization of pediatric hepatocellular carcinoma: genomic, methylomic and transcriptomic analysis [abstract]. In: Proceedings of the AACR Special Conference: Advances in the Pathogenesis and Molecular Therapies of Liver Cancer; 2022 May 5-8; Boston, MA. Philadelphia (PA): AACR; Clin Cancer Res 2022;28(17_Suppl):Abstract nr PO010.

Genomic Landscape of Metastatic Lymph Nodes and Primary Tumors in Non-Small-Cell Lung Cancer.

Objective: To investigate the genetic mutation characteristics of non-small cell lung cancers (NSCLC) with and without lymph node metastasis. Methods: Primary lesions and metastatic lymph node lesions of 36 Chinese NSCLC patients were tested for somatic mutations, tumor mutation burden, phylogenetic and clonal evolutional analysis using a 1021-gene panel by next-generation sequencing (NGS) with an average sequencing depth of 671X. Results: In this study, eighteen patients with lung adenocarcinoma (LUAD) and 18 with lung squamous cell carcinoma (LUSC) were included. Different groups had distinct characteristics of gene mutations. CTNNB1 gene mutations were only present in Nome_LC LUAD patients (p < 0.05). ARID1A mutation was however the only gene with significant alterations (p < 0.05) in Nome_LC in LUSC. Phylogenetic trees of mutated genes were also constructed. Linear and parallel evolutions of metastatic lymph nodes were observed both in LUAD and LUSC. Conclusion: LUSC exhibited more genetic mutations than LUAD. Intriguingly, there was significant difference in gene mutations between Meta_LC and Nome_LC. CTNNB1 gene alteration was the key mutation in LUAD that seems to promote proliferation of the tumor and then determine T stage. On the other hand, proliferation of the tumor was characterized by ARID1A missense mutation in LUSC, thus influencing the T stage as well. Lymph node metastasis could display both linear and parallel evolutionary characteristics in NSCLC. Different metastatic lymph nodes might have exactly the same or different mutated genes, underlining the heterogeneous genomic characteristics of these cancer types.

Abstract 1180: Discovery of CC-91516, a potent and selective ERK/NLK inhibitor, with anti-tumor activity in preclinical cancer models harboring BRAF or CTNNB1 mutation

Abstract CC-91516 (also called CC0776314), a selective and potent inhibitor of ERK1/2 and NLK, was discovered via a phenotypic screen of a kinase-focused library for compounds that synergize with mTOR kinase inhibitor CC-223 to induce apoptosis in combination with CC-223. Broad kinase selectivity profiling identified ERK1/2 and NLK as targets of CC-91516. Crystal structure of CC-91516 in complex with ERK2 reveals that its 2, 4, 6-trichlorophenyl moiety binds to a unique back pocket of the adenosine-5′-triphosphate (ATP) binding site of ERK2, which is not accessible to other ERK inhibitors such as BVD-523 and GDC-0994. This unique binding mode of CC-91516 leads to a slow off-rate for its ERK binding with long residence time disrupting both the active and inactive ERK forms. Consequentially, CC-91516 causes sustained inhibition of the MAPK pathway in BRAF mutant colorectal cancer cells. In addition, CC-91516 also regulates Wnt/β-catenin and YAP pathways in multiple cancer cell lines. CC-91516 shows potent yet selective anti-proliferative activity against a large panel of cancer cell lines. Activating mutations in BRAF or CTNNB1 gene associate with sensitivity to CC-91516-mediated anti-proliferative activity while mutations in RB and PI3K/PTEN pathway associate with resistance. CC-91516 inhibits ex vivo colony formation of PDX models with BRAF and CTNNB1 mutations. In addition, CC-91516 potently induces apoptosis, inhibits survival, and overcomes resistance to MEK inhibitor trametinib of BRAF or CTNNB1 mutant cancer cells in long-term culture assay in vitro. CC-91516 has good oral bioavailability and shows excellent anti-tumor activity in vivo against both BRAF and CTNNB1 mutant xenograft models. DMPK and toxicology studies showed robust oral exposure across preclinical species. In summary, CC-91516 has demonstrated preclinical anti-tumor activities and DMPK and safety profiles in support of its clinical development. Citation Format: Shuichan Xu, Tam Tran, Dan Zhu, Tao Shi, David Mikolon, Jim Leisten, Philip Chamberlain, Laurie LeBrun, Sogole Bahmanyar, Ning Jiang, Jingjing Zhao, Mehnaz Malek, Ellen Filvaroff, Heather Raymon, Robert Hubbard, John Boylan. Discovery of CC-91516, a potent and selective ERK/NLK inhibitor, with anti-tumor activity in preclinical cancer models harboring BRAF or CTNNB1 mutation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1180.

Investigating Susceptibility of ꞵ‐catenin‐mutated Hepatocellular Carcinoma to Checkpoint Inhibitors

Hepatocellular Carcinoma (HCC) is the 5th most common cause of cancer‐related death in the United States with an estimated 32,000 annual deaths. The standard of care for HCC as established by the IMBrave150 trial is a combination of the PD‐L1 inhibitor, Atezolizumab, and an antiangiogenic, Bevacizumab. While this combination extends overall survival to 19.2 months in unresectable HCC, only 52% of patients survive to 18 months. Furthermore, objective response rates are around 32% and hence clarifying underlying mechanisms regulating the immune response in HCC oncogenesis might strengthen immunotherapy efficacy. Especially important is to identify response rates of these agents in specific molecular subclasses of HCC may help in better patient selection. The oncogene ꞵ‐catenin is consistently mutated and activated among 30% of HCC patients. The Wnt/ꞵ‐catenin pathway has been approached as a target for precision medicine in HCC. We recently modeled HCCs with ꞵ‐catenin mutations in mice up to 69% genetic similarity. Here, we combine hydrodynamic tail vein injections with the Sleeping Beauty Transposase which is a non‐viral method of expressing genes of interest. Our model co‐expresses an S45Y point mutant of ꞵ‐catenin with the tyrosine kinase receptor MET (B+M). This combination represents ~10% of patient HCCs and provides a clinically relevant tool for the investigation of personalized HCC therapeutics.A recent study demonstrated HCCs driven by a Δ90‐truncation mutant of ꞵ‐catenin in combination with the Myc oncogene are shown to lack sufficient immune cell surveillance. These HCCs have poor cytotoxic T cell and dendritic cell recruitment while responding poorly to checkpoint inhibitors. Since activating point mutations in CTNNB1 gene are common in patient HCCs, we asked whether poor immune surveillance extends to HCC models harboring point mutations. We first checked and found the presence of CD45+, F4/80+, and CD11b+ cells both 2 and 4 weeks after B+M tumor induction. This indicates the presence of both adaptive and innate immune cells in the B+M tumor microenvironment. We next asked whether checkpoint inhibition will effectively reduce tumor burden in the B+M model. Therefore, we treated B+M mice with either IgG or anti‐PD1 monoclonal antibodies 4 weeks after tumor induction. Tissues were harvested 3.5 weeks after treatment. We found a modest 20% reduction in liver weight to body weight ratio, a measure of tumor burden, in B+M mice treated with anti‐PD1 compared to IgG controls. Our results demonstrate that HCCs with missense ꞵ‐catenin mutations do respond albeit marginally to checkpoint inhibitors. In the future, combination of checkpoint inhibitors with other inhibitors will be tested in these models to determine their efficacy in treating ꞵ‐catenin‐mutated HCCs.

Genomic profiling of gallbladder carcinoma: Targetable mutations and pathways involved

Gallbladder cancer (GBC) carries a poor prognosis and frequently present in late stages of disease. Identification of targetable molecular changes for selecting appropriate treatment and identifying prognostic and therapeutic subsets is required. Next-generation sequencing (NGS) using a frequently mutated for GBC may provide a reference for clinical management. The primary aim of the current study was to analyze the frequency of individual genetic alterations in GBC and to correlate with clinicopathological characteristics. A retrospective study was conducted using 22 gene panel examined NGS based approach for the detection of actionable genomic mutations in 37 GBC patients. The genetic and clinicopathological characteristics were analyzed. The number of mutations in cases was ranged from 1 to 15. A total of 171 mutations were identified in FFPE tissue DNA. The most common alterations were TP53 (90.90%), SMAD4 (60.60%), NOTCH1(45.45)& ERBB2 (45.45%), PIK3CA (33.33%) and MET (30.30)& PTEN (30.30%). Among the 22 gene panel, the TP53 gene was associated with histopathological differentiation (p = 0.0001), ERBB4 & ALK mutation was associated with necrosis (p = 0.012, 0.027), EGFR mutation was associated with mucin status (p = 0.023) and ERBB2 gene mutation was associated with T stage (p = 0.036). The study provides an overview of the genetic alterations in GBC patients.Targetable mutations are present in 89.91% cases of GBC which include SMAD4, NOTCH1, ERBB2&4, PIK3CA, MET, PTEN, EGFR, KRAS and BRAF. Metastatic disease was associated with high frequency of CTNNB1, KRAS and NRAS gene mutations.

Neuromuscular Choristoma: Report of Five Cases With CTNNB1 Sequencing.

Neuromuscular choristoma (NMC) are lesions of the peripheral nervous system characterized by an admixture of skeletal muscle fibers and nerves fascicles that are frequently associated with desmoid fibromatosis (DF). Mutations in CTNNB1, the gene for β-catenin protein, are common in DF and related to its pathogenesis. They are restricted to exon 3, with 3 point mutations: T41A, S45F, and S45P. To understand the pathogenesis of NMC, we tested CTNNB1 status in 5 cases of NMC whether or not they were associated with DF. The screening of mutations in CTNNB1 gene was based on amplicon deep sequencing using the ION Proton platform. Three patients had the S45F mutation; in 2 the mutation was common to both lesions and in one the DF was wild type while the NMC had the S45F mutation. One patient had a T41A mutation in the NMC and no associated DF. In the last patient, the DF lesion had a T41A mutation; there was no lesion with the S45P mutation. The presence of similar CTNNB1 mutations in NMC/DF-associated lesions and sporadic DF reinforces the relationship between both lesions and points to a common pathogenic mechanism.

Wnt/β-Catenin Signaling as a Driver of Hepatocellular Carcinoma Progression: An Emphasis on Molecular Pathways.

Liver cancers cause a high rate of death worldwide and hepatocellular carcinoma (HCC) is considered as the most common primary liver cancer. HCC remains a challenging disease to treat. Wnt/β-catenin signaling pathway is considered a tumor-promoting factor in various cancers; hence, the present review focused on the role of Wnt signaling in HCC, and its association with progression and therapy response based on pre-clinical and clinical evidence. The nuclear translocation of β-catenin enhances expression level of genes such as c-Myc and MMPs in increasing cancer progression. The mutation of CTNNB1 gene encoding β-catenin and its overexpression can lead to HCC progression. β-catenin signaling enhances cancer stem cell features of HCC and promotes their growth rate. Furthermore, β-catenin prevents apoptosis in HCC cells and increases their migration via triggering EMT and upregulating MMP levels. It is suggested that β-catenin signaling participates in mediating drug resistance and immuno-resistance in HCC. Upstream mediators including ncRNAs can regulate β-catenin signaling in HCC. Anti-cancer agents inhibit β-catenin signaling and mediate its proteasomal degradation in HCC therapy. Furthermore, clinical studies have revealed the role of β-catenin and its gene mutation (CTNBB1) in HCC progression. Based on these subjects, future experiments can focus on developing novel therapeutics targeting Wnt/β-catenin signaling in HCC therapy.

Clinicopathologic evaluation of CTNNB1 gene mutations in high-intermediate risk endometrial cancer

<h3>Objectives:</h3> <i>CTNNB1</i> mutations convey increased risk of recurrence in low risk endometrioid endometrial cancers. However, sub-analyses of high-intermediate risk (HIR) endometrioid endometrial cancers in other cohorts have not demonstrated a clearly increased recurrence risk and have often been equivocal. The objective of this study is to perform a clinicopathologic evaluation of patients with HIR endometrioid endometrial cancer in relation to <i>CTNNB1</i> mutational status. <h3>Methods:</h3> A single-institution chart review of patients diagnosed with endometrioid endometrial cancer between 2006 and 2018 was undertaken. Patients were classified as HIR according to GOG249 criteria. Mutational status was determined by Sanger sequencing of exon 3 of the <i>CTNNB1</i> gene in primary tumor specimens. Immunohistochemical (IHC) analysis of B-catenin was performed to evaluate for the presence of nuclear staining. Factors associated with recurrence were assessed by logistic regression; recurrence-free (RFS) and overall survival (OS) were assessed by Kaplan-Meier survival analysis. <h3>Results:</h3> 93 cases of HIR endometrioid endometrial cancer were identified, of which 23 (24.7%) were <i>CTNNB1</i> mutant and 70 (75.3%) were wild type. Median follow-up was 59.7 months. Recurrence occurred in 14/93 (15.1%) patients. Recurrence rates were not significantly different between patients with <i>CTNNB1</i> mutant and wild type tumors (13.0% vs. 15.9%, p=0.76). In both univariable and multivariable analyses, RFS and OS were not significantly different (RFS HR 0.88, p=0.85, 95% CI 0.24 - 3.17; OS HR 0.20, p=0.12, 95% CI 0.03 - 1.54). Predicted oncogenic mutations comprised 87% of all identified mutations and were present in 100% of recurrent tumors and 85% of non-recurrent tumors (p=0.47). Nuclear B-catenin expression by IHC demonstrated a sensitivity of 87% and a specificity of 83% for <i>CTNNB1</i> mutations. <h3>Conclusions:</h3> <i>CTNNB1</i> mutations have a prevalence of 25% in HIR endometrioid endometrial cancer. In this single institution retrospective study, there were no differences in RFS or OS in patients with <i>CTNNB1</i> mutant compared to wild-type tumors.

LncRNA NBR2 aggravates hepatoblastoma cell malignancy and promotes cell proliferation under glucose starvation through the miR-22/TCF7 axis

ABSTRACT Hepatoblastoma (HB) is the most commonly seen pediatric liver malignancy. With frequent mutations in CTNNB1 gene that encodes β‐catenin, hepatoblastoma has been considered as a Wnt/β‐catenin‐activated malignant tumor. Altered glucose metabolism upon nutrient deprivation (glucose starvation) might also be a critical event in hepatoblastoma carcinogenesis. The present study provides a lncRNA NBR2/miR-22/TCF7 axis modulating proliferation, invasion, migration, and apoptosis of hepatoblastoma cells upon glucose starvation through Wnt and downstream TCF7 signaling pathways. The expression of NBR2 is significantly increased within hepatoblastoma tissue samples; moreover, under incubation with 0 mM glucose (glucose starvation), NBR2 expression is significantly upregulated. NBR2 silencing not only inhibited hepatoblastoma cell viability, invasion, and migration under normal culture condition but also promoted the cell apoptosis under glucose starvation. NBR2 silencing in hepatoblastoma cells also decreased TCF7 mRNA expression and TCF7 protein levels, as well as the protein levels of the cell cycle, glucose entrapment, and EMT markers. miR-22 is directly bound to both NBR2 and TCF7; lncRNA NBR2 counteracted miR-22-mediated repression on TCF7 via acting as a ceRNA. The effects of NBR2 silencing on TCF7 expression, hepatoblastoma cell phenotype, and cell cycle, glucose entrapment, and EMT markers were all significantly reversed by miR-22 inhibition. In conclusion, lncRNA NBR2 aggravates hepatoblastoma cell malignancy through competing with TCF7 for miR-22 binding, therefore counteracting miR-22-mediated repression on TCF7. LncRNA NBR2 might be a promising target to inhibit hepatoblastoma cell proliferation under glucose starvation.

Abstract PO014: Clinicopathologic evaluation of CTNNB1 gene mutations in high-intermediate risk endometrial cancer

Abstract Background: CTNNB1 mutations convey increased risk of recurrence in low risk endometrioid endometrial cancers. However, sub-analyses of high-intermediate risk (HIR) endometrioid endometrial cancers in other cohorts have not demonstrated a clearly increased recurrence risk and have often been equivocal. The objective of this study is to perform a clinicopathologic evaluation of patients with HIR endometrioid endometrial cancer in relation to CTNNB1 mutational status. Methods: A single-institution chart review of patients diagnosed with endometrioid endometrial cancer between 2006 and 2018 was undertaken. Patients were classified as HIR according to GOG249 criteria. Mutational status was determined by Sanger sequencing of exon 3 of the CTNNB1 gene in primary tumor specimens. Immunohistochemical (IHC) analysis of B-catenin was performed to evaluate for the presence of nuclear staining. Factors associated with recurrence were assessed by logistic regression; recurrence-free (RFS) and overall survival (OS) were assessed by Kaplan-Meier survival analysis. Results: 93 cases of HIR endometrioid endometrial cancer were identified, of which 23 (24.7%) were CTNNB1 mutant and 70 (75.3%) were wild type. Median follow-up was 54.7 months. Recurrence occurred in 14/93 (15.1%) patients. Recurrence rates were not significantly different between patients with CTNNB1 mutant and wild type tumors (13.0% vs. 15.9%, p=0.76). In both univariable and multivariable analyses, RFS and OS were not significantly different (RFS HR 0.88, p=0.85, 95% CI 0.24 – 3.17; OS HR 0.20, p=0.12, 95% CI 0.03 – 1.54). Predicted oncogenic mutations comprised 87% of all identified mutations and were present in 100% of recurrent tumors and 85% of non-recurrent tumors (p=0.47). Nuclear B-catenin expression by IHC demonstrated a sensitivity of 87% and a specificity of 83% for CTNNB1 mutations. Conclusions: CTNNB1 mutations have a prevalence of 25% in HIR endometrioid endometrial cancer. In this single institution retrospective study, there were no differences in RFS or OS in patients with CTNNB1 mutant compared to wild-type tumors. Citation Format: Jennifer G. Haag, Rebecca J. Wolsky, Marisa R. Moroney, Jamie Sheren, Jeanelle Sheeder, Benjamin G. Bitler, Bradley R. Corr. Clinicopathologic evaluation of CTNNB1 gene mutations in high-intermediate risk endometrial cancer [abstract]. In: Proceedings of the AACR Virtual Special Conference: Endometrial Cancer: New Biology Driving Research and Treatment; 2020 Nov 9-10. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(3_Suppl):Abstract nr PO014.

Generation of a human induced pluripotent stem cell line (SBWCHi001-A) from a patient with NEDSDV carrying a pathogenic mutation in CTNNB1 gene.

Neurodevelopmental disorder with spastic diplegia and visual defects (NEDSDV) is a rare disease. Patients with NEDSDV are usually accompanied by microcephaly, severe mental retardation, spasticity, and global developmental delay. Recent studies showed that mutations in CTNNB1 are responsible for the phenotype. Here, we generated an induced pluripotent stem cell (iPSC) line (SBWCHi001-A) from an 18-month-old patient with NEDSDV, who harbored a de novo heterozygous mutation in CTNNB1. The transduced iPSCs expressed pluripotency markers, and could differentiate into three germ layers in vitro. This cell line will be a cell model to explore the pathogenesis of NEDSDV and discover potential therapies.

Lower Rate of CTNNB1 Mutations and Higher Rate of APC Mutations in Desmoid Fibromatosis of the Breast: A Series of 134 Tumors.

Desmoid fibromatosis (DF) is a rare, locally aggressive, nonmetastasizing fibroblastic/myofibroblastic tumor with a tendency to recur and an unpredictable clinical course. A "wait-and-see" policy is the new standard of care. DF are characterized by activating alterations of the wnt/β-catenin pathway: CTNNB1 or adenomatous polyposis coli gene (APC) mutations (these mutations being mutually exclusive). Desmoid-type fibromatosis of the breast (DFB) is rare with an incidence of 0.2% of breast tumors. The diagnosis of DFB is difficult, as it must be distinguished from metaplastic carcinoma and other spindle cell lesions. Sequencing of 128 DFB identified a lower rate of CTNNB1 mutations using Sanger (65.6%) or Sanger+next-generation sequencing (77.7%) and a higher rate of APC mutations (11.8%) than in all-site DF. By excluding patients with familial adenomatous polyposis (n=2), the rate of APC mutations in DFB was high (10.7%). The distribution of CTNNB1 mutations in DFB was different from all-site DF, with a higher rate of T41A (68.9%), a lower rate of S45F (5.7%), and a similar rate of S45T (12.6%). By combining the 2 molecular techniques in a 2-step manner (Sanger, then next-generation sequencing), we increased the detection rate of CTNNB1 mutations and lowered the rate of wild-type tumors from 34.4% to 9.8%, therefore improving the diagnosis of DFB. The identification of the exon 3 CTNNB1 mutation in breast spindle cell lesions is a highly specific tool for the diagnosis of DFB, in addition to extensive immunohistochemical analysis. Our study also underlines the importance of APC in DFB tumorigenesis. These findings have significant implications for patient care and management.