Cranial bone microarchitecture in a mouse model for syndromic craniosynostosis.

Crouzon syndrome is a congenital craniofacial disorder caused by mutations in the Fibroblast Growth Factor Receptor 2 (FGFR2). It is characterized by the premature fusion of cranial sutures, leading to a brachycephalic head shape, and midfacial hypoplasia. The aim of this study was to investigate the effect of the FGFR2 mutation on the microarchitecture of cranial bones at different stages of postnatal skull development, using the FGFR2C342Y mouse model. Apart from craniosynostosis, this model shows cranial bone abnormalities. High-resolution synchrotron microtomography images of the frontal and parietal bone were acquired for both FGFR2C342Y/+ (Crouzon, heterozygous mutant) and FGFR2+/+ (control, wild-type) mice at five ages (postnatal days 1, 3, 7, 14 and 21, n = 6 each). Morphometric measurements were determined for cortical bone porosity: osteocyte lacunae and canals. General linear model to assess the effect of age, anatomical location and genotype was carried out for each morphometric measurement. Histological analysis was performed to validate the findings. In both groups (Crouzon and wild-type), statistical difference in bone volume fraction, average canal volume, lacunar number density, lacunar volume density and canal volume density was found at most age points, with the frontal bone generally showing higher porosity and fewer lacunae. Frontal bone showed differences between the Crouzon and wild-type groups in terms of lacunar morphometry (average lacunar volume, lacunar number density and lacunar volume density) with larger, less dense lacunae around the postnatal age of P7-P14. Histological analysis of bone showed marked differences in frontal bone only. These findings provide a better understanding of the pathogenesis of Crouzon syndrome and will contribute to computational models that predict postoperative changes with the aim to improve surgical outcome.

Integrating Molecular Insights into Biliary Tract Cancer Management: A Review of Personalized Therapeutic Strategies.

Biliary tract cancers (BTCs) are rare and aggressive malignancies with an increasing incidence and poor prognosis. The standard systemic treatment for BTCs has evolved to include immune checkpoint inhibitors associated with gemcitabine-cisplatin as first-line therapies. However, survival rates remain low, highlighting the critical need for personalized treatment strategies based on molecular profiling. Currently, significant advancements have been made in the molecular characterization of BTCs, where genetic alterations, such as IDH1 mutations and FGFR2 fusions, provide targets for therapy. Molecular profiling is crucial early in the management process to identify potential candidates for clinical trials and guide treatment strategy. The integration of these molecular insights into clinical practice has allowed for the development of targeted therapies, although many of them are still in the phase 2 trial stage without definitive survival benefits demonstrated in phase 3 trials. This integration of comprehensive molecular profile insights with traditional treatment approaches offers a new horizon in the personalized medicine landscape for BTCs, with the aim of significantly improving patient outcomes through precision oncology.

FGFR2 and NOTCH1 Expression Inversely Correlated in Progressive Cutaneous Carcinogenesis in an Experimental Mouse Model.

Cutaneous squamous cell carcinoma (cSCC) is a common and increasingly prevalent form of skin cancer, posing significant health challenges. Understanding the molecular mechanisms involved in cSCC progression is crucial for developing effective treatments. The primary aim of this research was to evaluate the activation of NOTCH1 and FGFR2 oncogenes in inducing skin cancer in FVB/N mice through a stepwise chemical process. Forty female FVB/N mice, aged four weeks, were randomly divided into a control group (n = 8) and two experimental groups (group A: n = 16, group B: n = 16). This study involved subjecting the groups to a two-stage carcinogenesis procedure. This included an initial application of 97.4 nmol DMBA on shaved skin on their backs, followed by applications of 32.4 nmol TPA after thirteen weeks for group A and after twenty weeks for group B. The control group did not receive any treatment. Their skin conditions were monitored weekly to detect tumor development. After the experiment, the animals were euthanized for further tissue sampling. The examination of skin lesions in the experimental groups showed a correlation with tumor progression, ranging from dysplasia to carcinoma. Tumor samples were assessed both histologically and immunohistochemically. Notably, FGFR2 expression was higher in benign, precancerous, and malignant tumors compared to normal tissue. NOTCH1 expression was only elevated in benign tumors compared to normal tissue. This study demonstrates a clear correlation of FGFR2 expression and the progression of cutaneous neoplasms, while NOTCH 1 expression is inversely correlated in FVB/N mice. This suggests an early involvement of these oncogenes in the development of skin tumors.

Clinical features, MRI, molecular alternations, and prognosis of astrocytoma based on WHO 2021 classification of central nervous system tumors: A single-center retrospective study.

BACKGROUND: The diagnosis of glioma has advanced since the release of the WHO 2021 classification with more molecular alterations involved in the integrated diagnostic pathways. Our study aimed to present our experience with the clinical features and management of astrocytoma, IDH mutant based on the latest WHO classification. METHODS: Patients diagnosed with astrocytoma, IDH-mutant based on the WHO 5th edition classification of CNS tumors at our center from January 2009 to January 2022 were included. Patients were divided into WHO 2-3 grade group and WHO 4 grade group. Integrate diagnoses were retrospectively confirmed according to WHO 2016 and 2021 classification. Clinical and MRI characteristics were reviewed, and survival analysis was performed. RESULTS: A total of 60 patients were enrolled. 21.67% (13/60) of all patients changed tumor grade from WHO 4th edition classification to WHO 5th edition. Of these, 21.43% (6/28) of grade II astrocytoma and 58.33% (7/12) of grade III astrocytoma according to WHO 4th edition classification changed to grade 4 according to WHO 5th edition classification. Sex (p = 0.042), recurrent glioma (p = 0.006), and Ki-67 index (p < 0.001) of pathological examination were statistically different in the WHO grade 2-3 group (n = 27) and WHO grade 4 group (n = 33). CDK6 (p = 0.004), FGFR2 (p = 0.003), and MYC (p = 0.004) alterations showed an enrichment in the WHO grade 4 group. Patients with higher grade showed shorter mOS (mOS = 75.9 m, 53.6 m, 26.4 m for grade 2, 3, and 4, respectively, p = 0.01). CONCLUSIONS: Patients diagnosed as WHO grade 4 according to the 5th edition WHO classification based on molecular alterations are more likely to have poorer prognosis. Therefore, treatment should be tailored to their individual needs. Further research is needed for the management of IDH-mutant astrocytoma is needed in the future.

Synergic activity of FGFR2 and MEK inhibitors in the treatment of FGFR2-amplified cancers of unknown primary.

Patients with cancer of unknown primary (CUP) carry the double burden of an aggressive disease and reduced access to therapies. Experimental models are pivotal for CUP biology investigation and drug testing. We derived two CUP cell lines (CUP#55 and #96) and corresponding patient-derived xenografts (PDXs), from ascites tumor cells. CUP cell lines and PDXs underwent histological, immune-phenotypical, molecular, and genomic characterization confirming the features of the original tumor. The tissue-of-origin prediction was obtained from the tumor microRNA expression profile and confirmed by single-cell transcriptomics. Genomic testing and fluorescence in situ hybridization analysis identified FGFR2 gene amplification in both models, in the form of homogeneously staining region (HSR) in CUP#55 and double minutes in CUP#96. FGFR2 was recognized as the main oncogenic driver and therapeutic target. FGFR2-targeting drug BGJ398 (infigratinib) in combination with the MEK inhibitor trametinib proved to be synergic and exceptionally active, both in vitro and in vivo. The effects of the combined treatment by single-cell gene expression analysis revealed a remarkable plasticity of tumor cells and the greater sensitivity of cells with epithelial phenotype. This study brings personalized therapy closer to CUP patients and provides the rationale for FGFR2 and MEK targeting in metastatic tumors with FGFR2 pathway activation.

A case of treatment-resistant advanced gastric cancer with FGFR2 gene alteration successfully treated with pemigatinib.

Comprehensive genome profiling (CGP) is expected to widen the scope of cancer drug options by identifying the genes involved in carcinogenesis. However, a few patients can access recommended treatments following CGP. Herein, we report a case in which pemigatinib, a selective fibroblast growth factor receptor (FGFR) inhibitor, was used as last-line therapy to treat a patient with advanced gastric cancer exhibiting FGFR2 genomic alterations, as determined by CGP testing. The patient (male, 52 years old) was diagnosed with advanced gastric cancer (cStage IV, cT4aN3M1 [LYM], por, HER2 0, microsatellite stable) and received docetaxel + cisplatin + S-1 (7 cycles), irinotecan + ramucirumab (11 cycles), and nivolumab (3 cycles), but experienced progressive disease (PD). Subsequently, FoundationOne Liquid CDx testing was conducted, revealing FGFR2 rearrangement and amplification; however, no clinical trials on genotype-matched therapies for FGFR2 alterations were available. After three cycles of TAS-102, the patient experienced PD and provided consent for the off-label use of pemigatinib. The Cancer Genomics Medical Committee of our hospital approved the self-funded treatment. The patient had markedly decreased CEA and CA19-9 levels after treatment initiation, but experienced PD after five courses. Over the treatment course, grade 1 hyperphosphatemia and onychomadesis were observed. To the best of our knowledge, this is the first reported case of pemigatinib therapy employed in a patient with advanced gastric cancer exhibiting FGFR2 gene alterations. This case could serve as a notable example of tumor-agnostic therapy to broaden treatment options for gastric cancer patients with rare genetic alterations.

FGFR2 fusion/rearrangement is associated with favorable prognosis and immunoactivation in patients with intrahepatic cholangiocarcinoma.

Increasing evidence highlights that fibroblast growth factor receptor 2 (FGFR2) fusion/rearrangement shows important therapeutic value for patients with intrahepatic cholangiocarcinoma (ICC). This study aims to explore the association of FGFR2 status with the prognosis and immune cell infiltration profiles of patients with ICC. A total of 226 ICC tissue samples from patients who received surgery at the Department of Liver Surgery at Zhongshan Hospital, Fudan University, were collected retrospectively and assigned to a primary cohort (n = 152) and validation cohort (n = 74) group. Fluorescence in situ hybridization was performed to determine FGFR2 status. Multiplex immunofluorescence (mIF) staining and immunohistochemistry were performed to identify immune cells. Thirty-two (14.2%) ICC tissues presented with FGFR2 fusion/rearrangement. FGFR2 fusion/rearrangement was associated with low levels of carcinoembryonic antigen (CEA, P = .026) and gamma glutamyl transferase (γ-GGT, P = .003), low TNM (P = .012), CNLC (P = .008) staging as well as low tumor cell differentiation (P = .016). Multivariate COX regression analyses revealed that FGFR2 fusion/rearrangement was an independent protective factor for both overall survival (OS) and relapse-free survival in patients with ICC. Furthermore, correlation analysis revealed that an FGFR2 fusion/rearrangement was associated with low levels of Tregs and N2 neutrophils and high levels of N1 neutrophils infiltrating into tumors but not with CD8+ T-cell or macrophage tumor infiltration. FGFR2 fusion/rearrangement may exert a profound impact on the prognosis of ICC patients and reprogram the tumor microenvironment to be an immune-activated state. FGFR2 status may be used for ICC prognostic stratification and as an immunotherapeutic target in patients with ICC.

Molecular and morphologic characterization of intraductal tubulopapillary neoplasms of pancreas with novel potentially targetable fusions.

Intraductal tubulopapillary neoplasms (ITPNs) are rare pancreatic tumors with distinct histological and molecular features. Distinction of ITPN from other pancreatic neoplasms is crucial given the known favorable prognosis and the high frequency and diversity of potentially targetable fusions in ITPN. While the histological features of ITPN are well documented, there are few reports on the cytological features, and molecular characterization of ITPN. The authors reported three cases diagnosed in their laboratory between 2016 and 2021. Clinical data, cytomorphological and histological features, with immunophenotypic and molecular characterizations of these cases are described and compared with those reported in the literature. All 3 cases were diagnosed as ITPN based on the microscopic presence of intraductal nodules composed of tightly packed small tubular glands lined by cuboidal cells lacking apparent mucin. On molecular profiling KRAS and TP53 variants were found in Case 1, FGFR2-INA fusion in Case 2, and STARD3NL-BRAF fusion was detected in Case 3. Immunohistochemistry (IHC) revealed that the neoplastic cells in Case 1 were MUC2 positive and MUC6 negative, but in Cases 2 and 3, were negative for MUC2 and positive for MUC6. These results demonstrate the immunophenotypic and molecular variabilities of histologically similar pancreatic neoplasms. The absence of alterations characteristic of more common pancreatic neoplasms should prompt the consideration of fusion studies in morphologically relevant cases. The combination of morphological, IHC, and molecular analyses is important for reliable identification of ITPN given its potential clinical management implications.

Design, synthesis and antitumor activity of a novel FGFR2-selective degrader to overcome resistance of the FGFR2V564F gatekeeper mutation based on a pan-FGFR inhibitor.

Aberrant activation of fibroblast growth factor receptors (FGFRs) contributes to the development and progression of multiple types of cancer. Although many FGFR inhibitors have been approved by the FDA, their long-term therapeutic efficacy is hampered by acquired resistance to gatekeeper mutations and low subtype selectivity. FGFR2 has been found to be frequently amplified or mutated in many tumors. In this study, we designed several PROTACs with different E3 ligands based on LY2874455. By screening the length of the linker and the binding site in various degraders, we obtained a novel and highly efficient FGFR2-selective degrader 28e (DC50 = 0.645 nM, DCmax = 86 %). Compound 28e selectively degraded FGFR2 and essentially avoided degradation of FGFR1,3,4 isoforms (DC50 > 300 nM). Compound 28e significantly inhibited the proliferation of FGFR2-overexpressing cell lines, including KATOIII, SNU16, and AN3CA (IC50 = 0.794 nM/0.207 nM/4.626 nM), comparable to parental inhibitors. At the same time, the preferred compound showed superiority over the parental inhibitor in kinase inhibitory activity against the gatekeeper mutant isoform FGFR2V564F (IC50 = 0.121 nM). In summary, we identified 28e as a novel selective degrader of FGFR2 with high potency and high potential to overcome resistance to gatekeeper mutation. The discovery of 28e provides new evidence for the strategy of pan-inhibitor-based development of selective degrading agents.

Bemarituzumab plus mFOLFOX6 as first-line treatment in East Asian patients with FGFR2b-overexpressing locally advanced or metastatic gastric/gastroesophageal junction cancer: subgroup of FIGHT final analysis.

BACKGROUND: In the FIGHT study (NCT03694522) bemarituzumab, a humanized monoclonal antibody selective for fibroblast growth factor receptor 2b (FGFR2b), plus mFOLFOX6 showed clinically meaningful efficacy in patients with FGFR2b-positive (2+/3+ membranous staining by immunohistochemistry) locally advanced unresectable/metastatic gastric/gastroesophageal cancer (G/GEJC). A meaningful proportion of patients in FIGHT were enrolled in East Asia, reflecting global epidemiology of G/GEJC. METHODS: This subgroup analysis of the global, phase 2, double-blind FIGHT study included all patients enrolled in East Asian sites. Patients were randomized 1:1 to bemarituzumab-mFOLFOX6 (15 mg/kg and one 7.5 mg/kg dose on cycle 1, day 8) or matching placebo-mFOLFOX6. The primary endpoint was investigator-assessed progression-free survival (PFS). Secondary endpoints included overall survival (OS), objective response rate, and safety. Efficacy was evaluated after a minimum follow-up of 24 months. RESULTS: The East Asian subgroup comprised 89 patients (57% of overall study population); 45 were randomized to bemarituzumab-mFOLFOX6 and 44 to placebo-mFOLFOX6. Median PFS (95% confidence interval [CI]) was 12.9 months (8.8-17.9) with bemarituzumab-mFOLFOX6 and 8.2 months (5.6-10.3) with placebo-mFOLFOX6 (HR 0.50, 95% CI 0.29-0.87); median OS (95% CI) was 24.7 months (13.8-33.1) vs 12.9 months (9.3-21.4), respectively (HR 0.56, 95% CI 0.32-0.96). Treatment benefit was more pronounced in patients with FGFR2b-positive G/GEJC in ≥ 10% of tumor cells. No new safety signals were reported. CONCLUSION: In East Asian patients with FGFR2b-positive advanced/metastatic G/GEJC enrolled in the global FIGHT study, bemarituzumab-mFOLFOX6 showed clinically meaningful outcomes over placebo-mFOLFOX6.

Exploring a distinct FGFR2::DLG5 rearrangement in a low-grade neuroepithelial tumor: A case report and mini-review of protein fusions in brain tumors.

We report the novel clinical presentation of a primary brain neoplasm in a 30-year-old man with a mass-like area in the anteromedial temporal lobe. Histopathological analysis revealed a low-grade neuroepithelial tumor with cytologically abnormal neurons and atypical glial cells within the cerebral cortex. Molecular analysis showed a previously undescribed FGFR2::DLG5 rearrangement. We discuss the clinical significance and molecular implications of this fusion event, shedding light on its potential impact on tumor development and patient prognosis. Additionally, an extensive review places the finding in this case in the context of protein fusions in brain tumors in general and highlights their diverse manifestations, underlying molecular mechanisms, and therapeutic implications.

Do Fibroblast Growth Factor Receptor (FGFR) 2 and 3 Proteins Play a Role in Prognosis of Invasive Urothelial Bladder Carcinoma?

Background & Objective: Bladder carcinoma ranks second in prevalence among males in Egypt. As a family of tyrosine kinases, fibroblast growth factor receptor (FGFR) dysregulation has been linked to some malignancies in humans. The aim of this study is to analyze the clinicopathological data of patients while investigating FGFR2 and FGFR3 immunohistochemical expression in invasive urothelial bladder carcinoma. Methods: This retrospective cross-sectional study included 60 invasive urothelial carcinoma (UC) cases in the Pathology department, Faculty of Medicine, Menoufia University, from 2009 to 2020. All biopsies were stained for FGFR2 and FGFR3 antibodies. Complete clinical data were available for 44 patients treated and followed in clinical oncology and nuclear medicine departments. Results: Advanced stage and high grade are significantly correlated with FGFR2 positivity (P=0.048 and 0.044, respectively). Cases presented with Perineural invasion showed a higher percentage of FGFR2 (P=0.023). There is a significant indirect linear correlation between FGFR3 expression and lymph node positivity (r= -0.265, P=0.041). Conclusion: A high FGFR2 expression could be associated with poor prognostic parameters, while high FGFR3 expression would be associated with good prognostic parameters. These findings might highlight the importance of FGFR-targeted therapy as a FGFR2 antagonist and FGFR3 agonist for the treatment of urothelial carcinoma patients.

Generation of salivary glands derived from pluripotent stem cells via conditional blastocyst complementation.

Whole salivary gland generation and transplantation offer potential therapies for salivary gland dysfunction. However, the specific lineage required to engineer complete salivary glands has remained elusive. In this study, we identify the Foxa2 lineage as a critical lineage for salivary gland development through conditional blastocyst complementation (CBC). Foxa2 lineage marking begins at the boundary between the endodermal and ectodermal regions of the oral epithelium before the formation of the primordial salivary gland, thereby labeling the entire gland. Ablation of Fgfr2 within the Foxa2 lineage in mice leads to salivary gland agenesis. We reversed this phenotype by injecting donor pluripotent stem cells into the mouse blastocysts, resulting in mice that survived to adulthood with salivary glands of normal size, comparable to those of their littermate controls. These findings demonstrate that CBC-based salivary gland regeneration serves as a foundational experimental approach for future advanced cell-based therapies.

Circulating tumor DNA molecular analyses and real-world evidence outcomes of FGFR2 amplified gastroesophageal cancers.

PURPOSE: In addition to the existing biomarkers HER2 and PD-L1, FGFR2b has become an area of interest for the development of new targeted-based treatment. Given that clinical evaluation of FGFR2 targeted therapy is underway, we sought to elucidate the genomic landscape of FGFR2amp in gastroesophageal cancer (GEC) using a circulating tumor DNA (ctDNA) platform. MATERIALS AND METHODS: We retrospectively evaluated the Guardant Health database from 2017 to 2022 for patients with GECs with Guardant360 ctDNA next-generation sequencing (NGS) performed. We assessed co-occurring genetic alterations for patients who harbored FGFR2amp versus FGFR2null. We also explored real-world evidence database with Guardant Health, publicly available genomic databases (MSK cohort using cBioPortal), and pooled clinical data from large-volume cancer centers for FGFR2amp GECs. RESULTS: Less than 4% of patients with GEC in the Guardant Health database were identified to be FGFR2amp. The most commonly co-occurring gene mutations were TP53, CTNNB1, CDH1, and RHOA. Upon interrogation of the MSK cohort, these same genes were not significant on tissue NGS in the FGFR2amp cohort of GEC. In the pooled institutional cohort, we noted that FGFR2amp tumors were most commonly involving the gastroesophageal junction (GEJ). The overall survival of these patients was noted at 13.1 months. CONCLUSION: FGFR2 is a validated target in GECs, and the contexture of FGFR2amp will be important in defining patient subgroups with responses to FGFR2-directed therapy. Using ctDNA to provide a more detailed genomic landscape in patients with GECs will allow the advancement of targeted therapy in the near future for these aggressive cancers.

FGFR2-triggered autophagy and activation of Nrf-2 reduce breast cancer cell response to anti-ER drugs.

BACKGROUND: Genetic abnormalities in the FGFR signalling occur in 40% of breast cancer (BCa) patients resistant to anti-ER therapy, which emphasizes the potential of FGFR-targeting strategies. Recent findings indicate that not only mutated FGFR is a driver of tumour progression but co-mutational landscapes and other markers should be also investigated. Autophagy has been recognized as one of the major mechanisms underlying the role of tumour microenvironment in promotion of cancer cell survival, and resistance to anti-ER drugs. The selective autophagy receptor p62/SQSTM1 promotes Nrf-2 activation by Keap1/Nrf-2 complex dissociation. Herein, we have analysed whether the negative effect of FGFR2 on BCa cell response to anti-ER treatment involves the autophagy process and/or p62/Keap1/Nrf-2 axis. METHODS: The activity of autophagy in ER-positive MCF7 and T47D BCa cell lines was determined by analysis of expression level of autophagy markers (p62 and LC3B) and monitoring of autophagosomes' maturation. Western blot, qPCR and proximity ligation assay were used to determine the Keap1/Nrf-2 interaction and Nrf-2 activation. Analysis of 3D cell growth in Matrigel® was used to assess BCa cell response to applied treatments. In silico gene expression analysis was performed to determine FGFR2/Nrf-2 prognostic value. RESULTS: We have found that FGFR2 signalling induced autophagy in AMPKα/ULK1-dependent manner. FGFR2 activity promoted dissociation of Keap1/Nrf-2 complex and activation of Nrf-2. Both, FGFR2-dependent autophagy and activation of Nrf-2 were found to counteract the effect of anti-ER drugs on BCa cell growth. Moreover, in silico analysis showed that high expression of NFE2L2 (gene encoding Nrf-2) combined with high FGFR2 expression was associated with poor relapse-free survival (RFS) of ER+ BCa patients. CONCLUSIONS: This study revealed the unknown role of FGFR2 signalling in activation of autophagy and regulation of the p62/Keap1/Nrf-2 interdependence, which has a negative impact on the response of ER+ BCa cells to anti-ER therapies. The data from in silico analyses suggest that expression of Nrf-2 could act as a marker indicating potential benefits of implementation of anti-FGFR therapy in patients with ER+ BCa, in particular, when used in combination with anti-ER drugs.

A journey in the world of craniofacial development: From 1968 to the future.

This article is based on my talk at the meeting "3rd Advances in Craniosynostosis: Basic Science to Clinical Practice", held at University College, London, on 25 August 2023. It describes my contribution, together with that of my research team and external collaborators, to the field of craniofacial development. This began with my PhD research on the effects of excess vitamin A in rat embryos, which led to a study of normal as well as abnormal formation of the cranial neural tube. Many techniques for analysing morphogenetic change became available to me over the years: whole embryo culture, scanning and transmission electron microscopy, cell division analysis, immunohistochemistry and biochemical analysis of the extracellular matrix. The molecular revolution of the 1980s, and key collaborations with international research teams, enabled functional interpretation of some of the earlier morphological observations and required a change of experimental species to the mouse. Interactions between the molecular and experimental analysis of craniofacial morphogenesis in my laboratory with specialists in molecular genetics and clinicians brought my research journey near to my original aim: to contribute to a better understanding of the causes of human congenital anomalies.

Perinatal imaging findings of a fetus with Pfeiffer syndrome and a heterozygous c.1019A>G, p.Tyr340Cys (Y340C) mutation in FGFR2 presenting a cloverleaf skull, craniosynostosis and short limbs on prenatal ultrasound mimicking thanatophoric dysplasia type II.

OBJECTIVE: We present perinatal imaging findings of a fetus with Pfeiffer syndrome and a heterozygous c.1019A>G, p.Tyr340Cys (Y340C) mutation in FGFR2 presenting a cloverleaf skull, craniosynostosis and short limbs on prenatal ultrasound mimicking thanatophoric dysplasia type II (TD2). CASE REPORT: A 37-year-old, gravida 2, para 1, woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 46,XY. However, craniofacial anomaly was found on prenatal ultrasound at 21 weeks of gestation, which showed a cloverleaf skull with severe craniosynostosis and relatively short straight long bones. Fetal magnetic resonance imaging (MRI) analysis at 22 weeks of gestation showed a cloverleaf skull, proptosis and relatively shallowing of the sylvian fissures. Prenatal ultrasound at 24 weeks of gestation showed a fetus with a cloverleaf skull with a biparietal diameter (BPD) of 6.16 cm (equivalent to 24 weeks), an abdominal circumference (AC) of 18.89 cm (equivalent to 24 weeks) and a femur length (FL) of 3.65 cm (equivalent to 21 weeks). A tentative diagnosis of TD2 was made. The pregnancy was subsequently terminated, and a 928-g malformed fetus was delivered with severe craniosynostosis, proptosis, midface retrusion, a cloverleaf skull, broad thumbs and broad big toes. The broad thumbs were medially deviated. Whole body X-ray showed a cloverleaf skull and straight long bones. However, molecular analysis of FGFR3 on the fetus revealed no mutation in the target regions. Subsequent whole exome sequencing (WES) on the DNA extracted from umbilical cord revealed a heterozygous c.1019A>G, p.Tyr340Cys (Y340C) mutation in the FGFR2 gene. CONCLUSION: Fetuses with a Y340C mutation in FGFR2 may present a cloverleaf skull on prenatal ultrasound, and WES is useful for a rapid differential diagnosis of Pfeiffer syndrome from TD2 under such a circumstance.

Discovery of LHQ490 as a highly selective fibroblast growth factor receptor 2 (FGFR2) inhibitor.

Fibroblast growth factor receptor 2 (FGFR2) represents an appealing therapeutic target for multiple cancers, yet no selective FGFR2 inhibitors have been approved for clinical use to date. Here, we report the discovery of a series of new selective, irreversible FGFR2 inhibitors. The representative compound LHQ490 potently inhibited FGFR2 kinase activity with an IC50 of 5.2 nM, and was >61-, >34-, and >293-fold selective against FGFR1, FGFR3, and FGFR4, respectively. LHQ490 also exhibited high selectivity in a panel of 416 kinases. Cell-based studies revealed that LHQ490 efficiently suppressed the proliferation of BaF3-FGFR2 cells with an IC50 value of 1.4 nM, and displayed >70- and >714-fold selectivity against BaF3-FGFR1 and the parental BaF3 cells, respectively. More importantly, LHQ490 potently suppressed the FGFR2 signaling pathways, selectively inhibited FGFR2-driven cancer cell proliferation, and induced apoptosis of FGFR2-driven cancer cells. Taken together, this study provides a potent and highly selective FGFR2 inhibitor for further development of FGFR2-targeted therapeutic agents.

The combination of gemcitabine plus an anti-FGFR inhibitor can have a synergistic antitumor effect on FGF-activating cholangiocarcinoma.

Anti-FGFR treatment for cholangiocarcinoma (CCA) with fibroblast growth factor receptor (FGFR) alteration is a promising treatment option. Since the antitumor mechanisms of anti-FGFR inhibitors and conventional cytotoxic drugs differ, synergistic effects can be possible. This study aimed to evaluate the efficacy of the combined administration of gemcitabine (GEM) and pemigatinib in CCA cells with FGFR2 alterations. To simulate the treatment for patients with 3 kinds of CCA, chemonaïve CCA with activation of the FGF pathway, chemo-resistant CCA with activation of the FGF pathway, and CCA without FGF pathway activation (as controls), we evaluated 3 different CCA cell lines, CCLP-1 (with a FGFR2 fusion mutation), CCLP-GR (GEM-resistant cells established from CCLP-1), and HuCCT1 (without FGFR mutations). There was no significant difference between CCLP-1 and HuCCT1 in GEM suspensibility (IC50 = 19.3, 22.6 mg/dl, p = 0.1187), and the drug sensitivity to pemigatinib did not differ between CCLP-1 and CCLP-GR (IC50 = 7.18,7.60 nM, p = 0.3089). Interestingly, only CCLP-1 showed a synergistic effect with combination therapy consisting of GEM plus pemigatinib in vitro and in vivo. In a comparison of the reaction to GEM exposure, only CCLP-1 cells showed an increase in the activation of downstream proteins in the FGF pathway, especially FRS2 and ERK. In association with this reaction, cell cycle and mitosis were increased with GEM exposure in CCLP-1, but HuCCT1/CCLP-GR did not show this reaction. Our results suggested that combination therapy with GEM plus pemigatinib is a promising treatment for chemonaïve patients with CCA with activation of the FGF pathway.