GNAS Mutations Research Articles

Abstract 6152: Exploiting ferroptosis in mutant BAP1 uveal melanoma

Abstract Uveal melanoma (UM) arises from melanocytes of the uveal tract in the eye and is the most common intraocular malignancy in adults. Primary UM lesions often harbor mutations in G-proteins, GNAQ or GNA11, and are successfully treated by radiotherapy or enucleation. However, 50% of patients develop metastases. Of these metastatic UM (MUM) patients, 80%develop metastases to the liver, an effect strongly correlated with the loss of function of BAP1,a nuclear deubiquitinase. BAP1-mutant MUMs are less responsive to conventional treatments, such as chemotherapy and immune checkpoint inhibitors, with 50% of these patients having an overall survival of only 1 year. We propose that the unique metabolic intermediates found in liver microenvironment may dictate MUM tropism, aggressiveness, and poor therapeutic response. Here, using a combination of in vitro and ex vivo liver slice cultures, we found that the liver microenvironment induces gene expression alterations consistent with limiting the toxicity of reactive oxygen species (ROS). Importantly, we note that mutant BAP1 UM displayed improved ROS detoxification compared to its wildtype counterparts. Furthermore, publicly available datasets suggest patients with mutant BAP1 UM, the subset of patients with liver metastases, have corresponding ROS detoxification gene expression patterns. These findings suggest that the liver microenvironment and BAP1 loss directs MUM to mitigate ROS-associated toxicity. This compensatory mechanism may be therapeutically exploited and pair well as a combination treatment with the recently approved bispecific agent, Tebentafusp, to selectively target liver MUM. Citation Format: Camille J. Cunanan. Exploiting ferroptosis in mutant BAP1 uveal melanoma. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6152.

Expression of RANKL in breast cancer tissue in patients with fibrous dysplasia/McCune-Albright syndrome.

In fibrous dysplasia/McCune-Albright syndrome (FD/MAS), mosaic mutations in the GNAS gene lead to locally abnormal bone turnover. Additionally, patients with FD/MAS, particularly with thoracic lesions, have an increased risk for breast cancer. Development and progression of breast cancer has been associated with expression of Receptor Activator of NF-κB ligand (RANKL) in mammary tissue, and due to the GNAS mutation, RANKL is systemically increased in patients with FD/MAS. Yet it is unknown whether breast cancer in FD/MAS is also dependent on RANKL. We hypothesized that the GNAS mutation might induce RANKL overproduction and an oncogenic niche in mammary tissue, and examined RANKL expression in breast cancer tissue of patients with FD/MAS compared to controls. Nine patients with FD/MAS and breast cancer were included and clinical data were retrieved. Patients were matched to controls with breast cancer without FD/MAS based on age and tumor type. Three pregnant breast cancer patients were included as positive controls. Immunohistochemical detection of RANKL was performed on formalin-fixed paraffin-embedded breast cancer specimens. Staining intensity was classified as weak, moderate or intense. The area of positive RANKL staining divided by the total ductal-lobular area was assessed (positive area percentage, PAP). Number of patients with RANKL expression was compared between FD/MAS and control group by chi-square (χ2) test, the PAP by Mann-Whitney U test (MWU). RANKL expression was observed in 3 patients with FD/MAS (38%), mainly in healthy tissue, and none of the control patients (χ2p=0.055). The FD/MAS group demonstrated considerably more intense staining than the control group, comparable to positive controls. The median PAP was 0.64% (range 0.14-2.04%) in the 3 FD/MAS patients with RANKL expression, 0.01% (Q1-Q3: 0.0003-0.514%) in the entire FD/MAS group, 0.006% (Q1-Q3: 0.001-0.012%) in the control group (MWU=0.574), and 0.19% (0.08-0.32%) in the pregnant patients. All patients with FD/MAS and RANKL expression had thoracic bone lesions, but no correlation was observed between RANKL expression and presence of the GNAS mutation or FD disease burden. The triad of a higher number of patients, higher positive area percentage and stronger intensity in the FD/MAS compared to the control group indicates that RANKL may be upregulated in mammary tissue in a subset of patients with FD/MAS, which may explain the increased risk for breast cancer, although the clinical significance remains unclear. Further research is needed to establish risk profiles for the development of RANKL-positive breast cancer and to improve early screening and treatment.

Trametinib in Patients With NF1-, GNAQ-, or GNA11-Mutant Tumors: Results From the NCI-MATCH ECOG-ACRIN Trial (EAY131) Subprotocols S1 and S2.

NCI-MATCH is a precision medicine trial using genomic testing to allocate patients with advanced malignancies to targeted treatment subprotocols. This report combines two subprotocols evaluating trametinib, a MEK1/2 inhibitor, in patients with Neurofibromatosis 1 (NF1[S1] or GNA11/Q [S2]) altered tumors. Eligible patients had tumors with deleterious inactivating NF1 or GNA11/Q mutations by the customized Oncomine AmpliSeq panel. Prior MEK inhibitor treatment was excluded. Glioblastomas (GBMs) were permitted, including malignancies associated with germline NF1 mutations (S1 only). Trametinib was administered at 2 mg once daily over 28-day cycles until toxicity or disease progression. Primary end point was objective response rate (ORR). Secondary end points included progression-free survival (PFS) at 6 months, PFS, and overall survival. Exploratory analyses included co-occurring genomic alterations and PTEN loss. Fifty patients were eligible and started therapy: 46 with NF1 mutations (S1) and four with GNA11 mutations (S2). In the NF1 cohort, nonsense single-nucleotide variants were identified in 29 and frameshift deletions in 17 tumors. All in S2 had nonuveal melanoma and GNA11 Q209L variant. Two partial responses (PR) were noted in S1, one patient each with advanced lung cancer and GBM for an ORR of 4.3% (90% CI, 0.8 to 13.1). One patient with melanoma in S2 had a PR (ORR, 25%; 90% CI, 1.3 to 75.1). Prolonged stable disease (SD) was also noted in five patients (four in S1 and one in S2) with additional rare histologies. Adverse events were as previously described with trametinib. Comutations in TP53 and PIK3CA were common. Although these subprotocols did not meet the primary end point for ORR, significant responses or prolonged SD noted in some disease subtypes warrants further investigation.

Multiplex Digital PCR Assay to Detect Multiple KRAS and GNAS Mutations Associated with Pancreatic Carcinogenesis from Minimal Specimen Amounts

Digital PCR (dPCR) allows for highly sensitive quantification of low-frequency mutations and facilitates early detection of cancer. However, low-throughput targeting of single hotspots in dPCR hinders variant specification when multiple probes are used. We developed a dPCR method to simultaneously identify major variants related to pancreatic carcinogenesis. Using a two-dimensional plot of droplet fluorescence under the optimized concentration of two fluorescent probe pools, the absolute quantification of different KRAS and GNAS variants was determined. Successful detection of the multiple driver mutations was verified in 24 surgically resected tumor samples from 19 patients and 22 fine-needle aspiration samples from patients with pancreatic ductal adenocarcinoma. Precise quantification of the variant allele frequency was optimized by using template DNA at a concentration as low as 1 to 10 ng. Furthermore, amplicons targeting multiple hotspots were successfully enriched with fewer false-positive findings using high-fidelity polymerase, allowing for the detection of various KRAS and GNAS mutations with high probability in small amount of cell/tissue specimens. Using this target enrichment, mutations at a rate of 90% in small residual tissues, such as the fine-needle aspiration needle flush and microscopic lesions in resected specimens, were successfully identified. The proposed method allows for low-cost, accurate detection of driver mutations to diagnose cancers, even with minimal tissue collection.

Exceptionally rare IDH1-mutant adult medulloblastoma with concurrent GNAS mutation revealed by in vivo magnetic resonance spectroscopy and deep sequencing

Medulloblastoma (MB) is the most common malignant brain tumor occurring in childhood and rarely found in adults. Based on transcriptome profile, MB are currently classified into four major molecular groups reflecting a considerable biological heterogeneity: WNT-activated, SHH-activated, group 3 and group 4. Recently, DNA methylation profiling allowed the identification of additional subgroups within the four major molecular groups associated with different clinic-pathological and molecular features. Isocitrate dehydrogenase-1 and 2 (IDH1 and IDH2) mutations have been described in several tumors, including gliomas, while in MB are rarely reported and not routinely investigated. By means of magnetic resonance spectroscopy (MRS), we unequivocally assessed the presence the oncometabolite D-2-hydroxyglutarate (2HG), a marker of IDH1 and IDH2 mutations, in a case of adult MB. Immunophenotypical work-up and methylation profiling assigned the diagnosis of MB, subclass SHH-A, and molecular testing revealed the presence of the non-canonical somatic IDH1(p.R132C) mutation and an additional GNAS mutation, also rarely described in MB. To the best of our knowledge, this is the first reported case of MB simultaneously harboring both mutations. Of note, tumor exhibited a heterogeneous phenotype with a tumor component displaying glial differentiation, with robust GFAP expression, and a component with conventional MB features and selective presence of GNAS mutation, suggesting co-existence of two different major tumor subclones. These findings drew attention to the need for a deeper genetic characterization of MB, in order to get insights into their biology and improve stratification and clinical management of the patients. Moreover, our results underlined the importance of performing MRS for the identification of IDH mutations in non-glial tumors. The use of throughput molecular profiling analysis and advanced medical imaging will certainly increase the frequency with which tumor entities with rare molecular alterations will be identified. Whether these findings have any specific therapeutic implications or prognostic relevance requires further investigations.

Real-life use of trametinib after immunotherapy failure in BRAF wild-type advanced melanoma.

BRAF V600 wild-type advanced melanomas quickly reach a therapeutic dead-end, after immunotherapy failure. Even if preclinical studies have suggested sensitivity to MEK inhibitors such as trametinib in NRAS, NF1 or GNA mutated melanoma, therapeutic options are limited for these patients. We present a retrospective monocentric study of 22 patients with advanced melanoma treated by trametinib after immunotherapy resistance. Melanomas harboured NRAS (20), NF1 (1) or GNA 11 (1) mutations. For most of them (18), anti-PD1 was associated with trametinib. A disease-control was reported in 36% of patients (8/22), with six stable diseases and two partial responses according to Response Evaluation Criteria in Solid Tumors (RECIST) criteria. Median progression-free survival was 2 months (1-14) and median overall survival was 6.5 months (2-24). In patients with progressive disease (14/22), dissociated radiologic responses and clinical benefits such as pain reduction were seen in five patients. High blood level of lactate dehydrogenase (LDH) seemed associated with trametinib failure, without significance ( P = 0.06). Adverse events (grade 1-3) occurred in 91% of patients during the first weeks of treatment, mainly papulo-pustular rashes (77%), leg oedemas (36%), asthenia (18%) and diarrhoea (14%). This real-life study showed that trametinib may benefit some metastatic melanoma that progressed after chemotherapy and immune checkpoint inhibitors. Objective disease control (partial response or stable disease) using RECIST criteria was observed in 36% of patients. Because of frequent side-effects which can alter the quality of life and the short response duration, this off-label option has to be discussed with the patient. Studies with combination therapy with trametinib to improve relapse-free survival and lower side-effects are ongoing.

Circulating Tumor DNA as a Prognostic Factor in Patients With Resectable Hepatic Metastases of Uveal Melanoma.

We report here the results of a prospective study of circulating tumor DNA (ctDNA) detection in patients undergoing uveal melanoma (UM) liver metastases resection (NCT02849145). In UM patients, the liver is the most common and often only site of metastases. Local treatments of liver metastases, such as surgical resection, have a likely benefit in selected patients. Upon enrollment, metastatic UM patients eligible for curative liver surgery had plasma samples collected before and after surgery. GNAQ / GNA11 mutations were identified in archived tumor tissue and used to quantify ctDNA by droplet digital polymerase chain reaction which was then associated with the patient's surgical outcomes. Forty-seven patients were included. Liver surgery was associated with a major increase of cell-free circulating DNA levels, with a peak 2 days after surgery (∼20-fold). Among 40 evaluable patients, 14 (35%) had detectable ctDNA before surgery, with a median allelic frequency of 1.1%. These patients experienced statistically shorter relapse-free survival (RFS) versus patients with no detectable ctDNA before surgery (median RFS: 5.5 vs 12.2 months; hazard ratio=2.23, 95% CI: 1.06-4.69, P =0.04), and had a numerically shorter overall survival (OS) (median OS: 27.0 vs 42.3 months). ctDNA positivity at postsurgery time points was also associated with RFS and OS. This study is the first to report ctDNA detection rate and prognostic impact in UM patients eligible for surgical resection of their liver metastases. If confirmed by further studies in this setting, this noninvasive biomarker could inform treatment decisions in UM patients with liver metastases.

Neoplastic Progression in Intraductal Papillary Neoplasm of the Bile Duct.

Intraductal papillary neoplasm of the bile duct (IPNB) is classified into types 1 and 2 based on criteria proposed in 2019. Recent studies investigated the clinicopathologic and molecular features of IPNB, which contributed to a more detailed understanding of this undercharacterized neoplasm. To summarize driver gene mutations, radiologic tumor evolution, and a potentially unique pattern of tumor progression in IPNB. Data were derived from a literature review and personal clinical and research experiences. In contrast to de novo cholangiocarcinoma, type 1 IPNB often has mutations in APC, CTNNB1, STK11, and GNAS. These molecular features are shared with intraductal papillary mucinous neoplasm of the pancreas; however, the frequencies of individual gene abnormalities differ between these 2 neoplasms. A radiologic review of sequential images suggested that type 1 IPNB is a slow-growing neoplasm, with an ∼1-cm increase in size every 2 to 3 years, and remains in a noninvasive state for many years. A similar papillary neoplasm may develop in the biliary tree years after the complete surgical resection of IPNB. The second neoplasm has the same genetic abnormalities as the first neoplasm, indicating intrabiliary implantation rather than multifocal lesions. In contrast to type 1 IPNB, most cases of type 2 IPNB have invasive malignancy at the initial presentation. Type 2 IPNB shares many clinicopathologic and molecular features with de novo cholangiocarcinoma, questioning the distinctness of this tumor entity. The molecular mechanisms underlying malignant transformation in IPNB warrant further study.

Tissue factor expression in colorectal cancer.

250 Background: Tissue factor (TF), a component of the coagulation cascade, transmembrane receptor, and cofactor for factor VII/VIIa is expressed by subendothelial cells and critical to hemostasis, thrombosis, cell proliferation, angiogenesis, and metastasis. TF is suggested to have a critical role in colorectal cancer (CRC). Here we assessed the clinico-molecular features associated with TF expression (exp) in CRC. Methods: Tumor molecular profiling was performed for 14,0786 samples by NextGen Sequencing on DNA (592 genes or WES) and RNA (WTS) and immunohistochemistry (IHC) at Caris Life Sciences (Phoenix, AZ). TF-high (TF-H) and TF-low (TF-L) RNA exp were defined as ≥ 75th- and < 25th-percetile of TF transcripts per million (TPM), respectively. X2/Fisher-exact and Mann Whitney U tests were used for comparison, and P-values were adjusted for multiple comparisons. Cell infiltration in the tumor microenvironment (TME) was estimated by quanTIseq. Real-world overall survival (OS) information was obtained from insurance claims data and Kaplan-Meier estimates were calculated for molecularly defined patients (pts). Results: TF exp was higher in primary tumors compared to metastatic sites (2.3-fold, P < 0.001); higher in lung vs. liver metastases (0.6-fold and 0.3-fold, p < 0.001); higher in rectal (1.4-fold), right-sided (1.3-fold), and transverse (1.2-fold) compared to left-sided (P < 0.001); and highest in CMS1 tumors (CMS2 0.4-fold, CMS3 0.7-fold, CMS4 0.8-fold, P < 0.001). TF exp was higher in tumors with high TMB (TMB ≥ 10 Mut/Mb) (1.6-fold), dMMR/MSI-H (1.9-fold), and PD-L1 exp (1.8-fold) (P < 0.001 each). Compared to WT tumors, mutations in KRAS (1.2-fold, P < 0.001), BRAF (1.5-fold, P < 0.001) and ERBB2 (1.2-fold, P < 0.01) were associated with higher TF exp. In pMMR/MSS CRC, TF-L tumors were associated with TP53, APC, and NRAS mutations, and TF-H was associated with KRAS, PIK3CA, SMAD4, FBXW7, BRAF, ARID1A, GNAS, SMAD2, RNF43, KMT2D and BRCA1 mutations. TF exp was positively associated with most immune cell populations, most strongly with endothelial cells. In pMMR/MSS KRAS WT CRC, TF-H was associated with worse OS than TF-L. TF-H was also associated with worse OS for pMMR/MSS CRC pts treated with FOLFOX (HR: 1.5, CI:1.2-1.8, p < 0.0001), FOLFIRI (HR:1.7, CI:1.3-2.1, p < 0.0001), VEGF (HR:1.3, CI:1.1-1.6, p = 0.002) and EGFR inhibitors (HR:1.6, CI:1.1-2.3, p = 0.009) than TF-L. TF-H was associated with greater median days on pembrolizumab compared to TF-L in dMMR/MSI-H CRC (HR: 0.6, CI: 0.4-0.9, p = 0.018). Conclusions: Our data show TF exp is associated with distinct clinical and molecular features, including tumor sidedness and metastatic pattern, as well as CMS subtype and KRAS, BRAF and ERBB2 mutations. TME cell infiltration and IO-related biomarkers were enriched in TF-H, with TF exp correlating with endothelial cell abundance. These findings and associations with patient outcomes suggest that TF may be a relevant biomarker and target in CRC.

Comparative analysis of the molecular profile and tumor immune microenvironment (TIME) of human epidermal growth factor receptor 2 (HER2) low (L)- versus high (H)-expressing gastroesophageal cancers (GEC).

287 Background: Addition of immune checkpoint blockade to anti-HER2 therapy has improved outcomes in HER2-positive GEC. Anti-HER2 antibody-drug conjugates have shown activity in some HER2-L tumors in other tumor types. We aimed to compare the molecular profile and TIME of HER2-L and HER-H GEC. Methods: 8678 GEC (gastric, GE junction, and esophageal) adenocarcinoma and squamous cell carcinoma samples were analyzed by next-generation sequencing (NGS) of RNA (whole transcriptome, NovaSeq), DNA (592 genes, NextSeq, or whole exome sequencing, NovaSeq), and immunohistochemistry (IHC, Caris Life Sciences, Phoenix, AZ). Cohorts were stratified by IHC HER2 values of 0 (non-expressors), 1-2+ (HER2-L), or 3+ (HER2-H) and compared using X2 or Fisher-Exact. Statistical significance was determined as P-value adjusted for multiple comparisons (q < 0.05). Microenvironment cell population (MCP) counter was used to quantify immune cell infiltration. Results: Tumor were grouped into HER2 non-expressors (N = 5217), L (N = 2660), and H (N = 801). Mutations of TP53 (72% vs 92%) and amplification of MYC (4% vs 7%), CCNE1 (7% vs 12%), CCND3 (2% vs 4%), CDK6 (3% vs 6%), SMARCE1 (2% vs 25%) and RARA (3% vs 24%) were significantly lower in HER2-L compared to HER2-H (q < 0.05). ARID1A (14% vs 9%), PIK3CA (8% vs 3%), KRAS (9% vs 2%), GNAS (2% vs 0.3%), KMT2D (6% vs 1%), CDH1 (5% vs 1%), and ATM (4% vs 1%) mutations were significantly higher in HER2-L compared to HER2-H (q < 0.05). HER2-L was associated with more TMB-H (9.3% vs. 5%; q<0.05), MSI-H (4.7% vs. 0.6%; q<0.05), and a trend towards higher PD-L1 expression than in HER2-H (80.8% vs 76.1%, p < 0.05 but q > 0.05). Immuno-oncology (IO)-related gene expression inversely correlated with HER2 expression with lowest expression of PDCD1LG2, CD274, CTLA4, PDCD1, HAVCR2, CD80, IFNG, LAG3, and CD86 in HER2-H (q < 0.05). HER2-L had significantly higher median immune infiltration of B cells (fold change [FC]: 1.22), T cells (FC: 1.16), CD8+ T cells (FC: 1.56), NK cells (FC: 1.12), neutrophils (FC: 1.10), cytotoxic lymphocytes (FC: 1.36), and myeloid dendritic cells (FC: 1.34), compared to HER2-H (q < 0.05). HER2 non-expressors showed similar immune cell infiltrates compared to HER2-H. HER2-H was associated with lower T-cell inflamed scores and IFN gamma signature when compared to HER2-L and non-expressors (q < 0.05). Conclusions: To our knowledge, this study is the first and largest comparison of molecular profile and TIME in HER2-expressing GEC. We demonstrated distinct molecular and TIME profiles with higher immunogenic profiles in HER-L as compared to HER2-H. IO-related gene expression and TIME cell distribution differences in HER2-H GEC suggest that response to IO and HER2 therapy combinations is likely related to HER2-targeted treatment effect on TIME rather than baseline immunogenicity of the tumor.

Cerivastatin Synergizes with Trametinib and Enhances Its Efficacy in the Therapy of Uveal Melanoma.

Metastatic uveal melanoma (MUM) is a highly aggressive, therapy-resistant disease. Driver mutations in Gα-proteins GNAQ and GNA11 activate MAP-kinase and YAP/TAZ pathways of oncogenic signalling. MAP-kinase and MEK-inhibitors do not significantly block MUM progression, likely due to persisting YAP/TAZ signalling. Statins inhibit YAP/TAZ activation by blocking the mevalonate pathway, geranyl-geranylation, and subcellular localisation of the Rho-GTPase. We investigated drugs that affect the YAP/TAZ pathway, valproic acid, verteporfin and statins, in combination with MEK-inhibitor trametinib. We established IC50 values of the individual drugs and monitored the effects of their combinations in terms of proliferation. We selected trametinib and cerivastatin for evaluation of cell cycle and apoptosis. Synergism was detected using isobologram and Chou-Talalay analyses. The most synergistic combination was tested in vivo. Synergistic concentrations of trametinib and cerivastatin induced a massive arrest of proliferation and cell cycle and enhanced apoptosis, particularly in the monosomic, BAP1-mutated UPMM3 cell line. The combined treatment reduced ERK and AKT phosphorylation, increased the inactive, cytoplasmatic form of YAP and significantly impaired the growth of UM cells with monosomy of chromosome 3 in NSG mice. Statins can potentiate the efficacy of MEK inhibitors in the therapy of UM.

Molecular profiling of primary uveal melanoma: results of a Polish cohort.

There is no published data regarding the molecular alterations of Polish patients with primary uveal melanoma. We performed whole exome sequencing of 20 primary uveal melanomas (UMs), 10 metastasizing and 10 non-metastasizing cases to identify significant molecular alterations. We detected mutations and copy number variants in the BAP1 gene in 50% (10 cases) of the cases. GNA11 mutations were detected in 50% (10 cases) including nine p.Q209L and one p.R183C. GNAQ mutations gene were detected in 40% (8 cases) and all were p.Q209P. SF3B1, EIF1AX, PLCB4 , and PALB2 mutations were detected in one case each. Genetic aberrations of FBXW7 were detected in 55% of cases, with copy number loss of 10 and missense mutation in one. Gain or loss of copy number was observed in 60%, 60%, and 10% of cases in MYC, MLH1 , and CDKN2A genes, respectively. BAP1 and GNAQ tumor suppressor genes are more often mutated in UM with metastasis, while GNA11 mutations are more frequently detected in non-metastasizing tumors. MYC copy gain was present twice as frequently (80% versus 40%) in cases with versus those without metastases. BAP1 mutation correlated with worse overall survival; while GNA11 mutation and CDKN2A loss correlated with better and worse progression-free survival, respectively. We have confirmed BAP1 prognostic potential and documented frequent MYC amplification in metastasizing cases. Although GNA11 mutation and CDKN2A loss significantly correlated with progression-free survival in our study, our sample size is small. The prognostic significance of GNAQ/GNA11 mutation and CDKN2A loss would require further investigation.

Brain Metastases from Biliary Tract Cancer: Case Series and Clinicogenomic Analysis.

Limited data from small series have suggested that brain metastases from biliary tract cancers (BrM-BTC) affect ≤2% of patients with BTC. We sought to review our experience with patients with BrM-BTC and to identify associations of tumor-related molecular alterations with outcomes. A retrospective review of patients with BTC seen at a tertiary referral center from 2005 to 2021 was performed; patients with BrM-BTC were identified, and clinical and molecular data were collected. Twenty-one of 823 patients with BTC (2.6%) developed BrM. For patients with BrM-BTC, median follow-up time was 27.9 months after primary BTC diagnosis and 3.1 months after BrM diagnosis. Median time from primary diagnosis to diagnosis of BrM was 14.4 [range, 1.1-66.0] months. Median overall survival (OS) from primary diagnosis was 31.5 [2.9-99.8] months and median OS from BrM diagnosis was 4.2 [0.2-33.8] months. Patients who underwent BrM-directed therapy trended toward longer OS following BrM diagnosis than patients receiving supportive care only (median 6.5 vs 0.8 months, P = .060). The BrM-BTC cohort was enriched for BRAF (30%), PIK3CA (25%), and GNAS (20%) mutations. patients with BrM-BTC with BRAF mutations trended toward longer OS following BrM diagnosis (median 13.1 vs 4.2 months, P = .131). This is the largest series of patients with BrM-BTC to date and provides molecular characterization of this rare subgroup of patients with BTC. Patients with BrM-BTC may be more likely to have BRAF mutations. With advances in targeted therapy for patients with BTC with actionable mutations, continued examination of shifting patterns of failure, with emphasis on BrM, is warranted.

Prevalence of Chiari malformation type 1 is increased in pseudohypoparathyroidism type 1A and associated with aberrant bone development.

Albright hereditary osteodystrophy (AHO) is caused by heterozygous inactivating mutations in GNAS. Patients with maternally-inherited mutations develop pseudohypoparathyroidism type 1A (PHP1A) with multi-hormone resistance and aberrant craniofacial and skeletal development among other abnormalities. Chiari malformation type 1 (CM1), a condition in which brain tissue extends into the spinal canal when the skull is too small, has been reported in isolated cases of PHP1A. It has been hypothesized to be associated with growth hormone (GH) deficiency. Given the adverse clinical sequelae that can occur if CM1 goes unrecognized, we investigated the previously undetermined prevalence of CM1, as well as any potential correlations with GH status, given the known increased prevalence of GH deficiency in PHP1A. We also investigated these metrics for low lying cerebellar tonsils (LLCT), defined as tonsillar descent less than 5 mm below the foramen magnum. In addition, we investigated possible correlations of CM1/LLCT with advanced hand/wrist bone ages and craniofacial abnormalities known to occur in PHP1A to determine whether premature chondrocyte differentiation and/or aberrant craniofacial development could be potential etiologies of CM1/LLCT through both human studies and investigations of our AHO mouse model. We examined patients with PHP1A in our clinic and noticed CM1 more frequently than expected. Therefore, we set out to determine the true prevalence of CM1 and LLCT in a cohort of 54 mutation-confirmed PHP1A participants who had clinically-indicated brain imaging. We examined potential correlations with GH status, clinical features, biological sex, genotype, and hand/wrist bone age determinations. In addition, we investigated the craniofacial development in our mouse model of AHO (Gnas E1+/-m) by histologic analyses, dynamic histomorphometry, and micro-computerized tomographic imaging (MCT) in order to determine potential etiologies of CM1/LLCT in PHP1A. In our cohort of PHP1A, the prevalence of CM1 is 10.8%, which is at least 10-fold higher than in the general population. If LLCT is included, the prevalence increases to 21.7%. We found no correlation with GH status, biological sex, genotype, or hand/wrist bone age. Through investigations of our Gnas E1+/-m mice, the correlate to PHP1A, we identified a smaller cranial vault and increased cranial dome angle with evidence of hyperostosis due to increased osteogenesis. We also demonstrated that there was premature closure of the spheno-occipital synchondrosis (SOS), a cartilaginous structure essential to the development of the cranial base. These findings lead to craniofacial abnormalities and could contribute to CM1 and LLCT development in PHP1A. The prevalence of CM1 is at least 10-fold higher in PHP1A compared to the general population and 20-fold higher when including LLCT. This is independent of the GH deficiency that is found in approximately two-thirds of patients with PHP1A. In light of potential serious consequences of CM1, clinicians should have a low threshold for brain imaging. Investigations of our AHO mouse model revealed aberrant cranial formation including a smaller cranium, increased cranial dome angle, hyperostosis, and premature SOS closure rates, providing a potential etiology for the increased prevalence of CM1 and LLCT in PHP1A.

Whole-genome sequencing revealed a novel long-range deletion mutation spanning GNAS in familial pseudohypoparathyroidism.

Pseudohypoparathyroidism (PHP) is a series of diseases related to pathological changes and neurocognitive and endocrine abnormalities, mainly due to the GNAS mutation on chromosome 20q13.2, which weakens receptor-mediated hormone signal transduction. Considering its complex genetic and epigenetic characteristics, GNAS may produce complex clinical phenotypes in families or sporadic cases. This study presented a case of familial PHP caused by a deletion mutation in the 20q13.2 region. The proband and her second daughter had PHP, and the proband's mother had pseudo-PHP. Whole-genome sequencing revealed that the proband had an 849.81 kb deletion spanning GNAS near the maternal 20q13.2 chromosome. Multiplex ligation-dependent probe amplification methylation analysis indicated that the proband as well as her mother and second daughter had seemingly abnormal GNAS methylation. This is different from the phenotype (feeding difficulty, slow growth, and special facial features) of previously reported cases with the deletion of fragments near the 20q13.2 chromosome. This report demonstrated the variability of 20q13.2 deletion phenotypes and the clinical importance of using multiple molecular genetic detection methods.

PS-BPR01-7: CONCURRENT SOMATIC MUTATIONS IN CTNNB1 AND GNA11 IN AN ALDOSTERONE-PRODUCING ADENOMA

Background: Aldosterone-producing adenoma (APA) is a major subtype of primary aldosteronism (PA), a common form of secondary hypertension. In the past decade, there has been significant progress in the determination of genetic causes of APA. The use of next-generation sequencing (NGS) has led to the identification of somatic mutations in APA that cause excess aldosterone production. Most of the affected genes encode ion channels or transporters. Somatic activating mutations in CTNNB1 (β;-catenin) have also been detected in 2–5% of APA. As a possible pathogenesis, an association of CTNNB1-mutated APA with pregnancy and menopause has been proposed. A recent study reported double somatic mutations in CTNNB1 and GNA11/Q in APA. However, due to its rare incidence, characteristics of APA with these mutations are not well determined. Herein, we report a case of APA harboring somatic CTNNB1 and GNA11 mutations. Case presentation: A 46-year-old Japanese woman presented with hypertension and spontaneous hypokalemia. She had no history of pregnancy-induced hypertension. She had regular menstrual cycle at presentation. Endocrine testing showed elevated plasma aldosterone concentration (677.5 pg/mL) under suppressed renin (plasma renin activity, 0.3 ng/mL/h). Computed tomography revealed a 2 cm right adrenal mass. Adrenal venous sampling indicated excess aldosterone production from the right adrenal gland. NP-59 scintigraphy further demonstrated increased tracer uptake in the right adrenal lesion. She underwent right laparoscopic adrenalectomy. Histologic diagnosis of the resected tumor was adrenocortical adenoma based on the Weiss criteria. Notably, Ki-67 labeling index was high (6% at hotspots). After surgery, her blood pressure and serum potassium both normalized. Based on the PASO (the primary aldosteronism surgical outcome) study criteria, PA remained clinically and biochemically cured at follow-up 18 months after surgery. Methods: Formalin-fixed, paraffin-embedded adrenal tumor tissue was used for immunohistochemical and genetic analysis. Results: Immunohistochemistry (IHC) showed high and diffuse expression of CYP11B2 (aldosterone synthase) within the tumor, whereas 11β;-hydroxylase (CYP11B1, a steroidogenic enzyme for cortisol biosynthesis) was mostly negative. VSNL1, a marker for the zona glomerulosa where physiologic aldosterone biosynthesis occurs, was highly expressed within the tumor. CYP11B2 IHC-guided targeted NGS identified concurrent somatic CTNNB1 (p.D32Y) and GNA11 (p.Q209H) mutations with similar variant allele frequencies (29.5% and 29.7%, respectively). Conclusions: To best of our knowledge, this is the first Asian case of APA with CTNNB1 and GNA11 mutations. Detailed clinical and histologic examination would provide useful information for better characterization of patients with PA due to these rare mutations.

Vrednosti kalcitonina u pseudohipoparatiroidizmu

Pseudohypoparathyroidism type 1A is a rare endocrine disorder caused by GNAS mutation and the resulting hormone resistance at the receptor level, i.e. the activation of the intracellular pathway of the Gs alpha subunit is not possible. This disorder is most often characterized by resistance to the parathyroid hormone. However, it can also be characterized by resistance to other hormones, such as thyroid-stimulating hormone, gonadotropins (luteinizing and follicle-stimulating hormones), growth hormone-releasing hormone, and calcitonin. In this article, we describe the case of a patient diagnosed with pseudohypoparathyroidism based on phenotypic features of hereditary Albright osteodystrophy. Due to the progressive decline in intellectual functions and changing behavior, neurological examination confirmed calcifications of the CNS as part of Fahr's syndrome. During hospitalization, higher levels of thyroid-stimulating hormone and calcitonin were observed, probably as a result of resistance at the level of the receptor and its intracellular pathway. Hypercalcitoninemia occurs sporadically in cases involving pseudohypoparathyroidism type 1-a and type 1-b. Elevated levels of calcitonin should be evaluated by means of anamnesis and clinical examination involving morphological and functional tests, considering that a highly specific tumor is a marker of medullary carcinoma of the thyroid gland, as well as some neuroendocrine tumors. Some authors recommend fine needle aspiration biopsy in order to minimize the risk of medullary thyroid cancer.

The hallmarks of cancer… in pituitary tumors?

Over 20years ago, Hanahan and Weinberg published a seminal review that addressed the biological processes that underly malignant transformation. This classical review, along with two revisions published in 2011 and 2022, has remain a classic of the oncology literature. Since many of the addressed biological processes may apply to non-malignant tumorigenesis, we evaluated to what extent these hallmarks pertain to the development of pituitary adenomas.Some of the biological processes analyzed in this review include genome instability generated by somatic USP8 and GNAS mutations in Cushing's diseases and acromegaly respectively; non-mutational epigenetic reprograming through changes in methylation; induction of angiogenesis through alterations of VEGF gene expression; promotion of proliferative signals mediated by EGFR; evasion of growth suppression by disrupting cyclin dependent kinase inhibitors; avoidance of immune destruction; and the promotion of inflammation mediated by alteration of gene expression of immune check points. We also elaborate further on the existence of oncogene induced senescence in pituitary tumors. We conclude that a better understanding of these processes can help us dilucidated why pituitary tumors are so resistant to malignant transformation and can potentially contribute to the development of novel anticancer treatments.

Molecular Classification of Appendiceal Adenocarcinoma.

Appendiceal adenocarcinomas (ACs) are rare, histologically diverse malignancies treated as colorectal cancers despite having distinct biology and clinical behavior. To guide clinical decision making, we defined molecular subtypes of AC associated with patient survival, metastatic burden, and chemotherapy response. A comprehensive molecular analysis was performed in patients with AC to define molecular subtypes. Associations between molecular subtype and overall survival, intraoperative peritoneal cancer index, and first-line chemotherapy response were assessed adjusting for histopathologic and clinical variables using multivariable Cox proportional hazards, linear regression, and logistic regression models. We defined distinct molecular lineages of mucinous appendiceal adenocarcinoma (MAAP) from co-occurring mutations in GNAS, RAS, and TP53. Of 164 MAAP tumors, 24 were RAS-mutant (mut) predominant (RAS-mut/GNAS-wild-type [wt]/TP53-wt) with significantly decreased mutations and chromosomal alterations compared with tumors with GNAS mutations (GNAS-mut predominant) or TP53 mutations (TP53-mut predominant). No patient with RAS-mut predominant subtype metastatic MAAP died of cancer, and overall survival in this subgroup was significantly improved compared with patients with GNAS-mut (P = .05) and TP53-mut (P = .004) predominant subtypes. TP53-mut predominant subtypes were highly aneuploid; increased tumor aneuploidy was independently (P = .001) associated with poor prognosis. The findings retained significance in patients with any metastatic AC. RAS-mut predominant metastases exhibited reduced peritoneal tumor bulk (P = .04) and stromal invasion (P < .001) compared with GNAS-mut or TP53-mut predominant tumors, respectively. Patients with RAS-mut predominant MAAP responded more to first-line chemotherapy (50%) compared with patients with GNAS-mut predominant tumors (6%, P = .03). AC molecular patterns identify distinct molecular subtypes: a clinically indolent RAS-mut/GNAS-wt/TP53-wt subtype; a chemotherapy-resistant GNAS-mut predominant subtype; and an aggressive, highly aneuploid TP53-mut predominant subtype. Each subtype exhibits conserved clinical behavior irrespective of histopathology.

Transcriptomic Classification of Pituitary Neuroendocrine Tumors Causing Acromegaly

Acromegaly results from growth hormone hypersecretion, predominantly caused by a somatotroph pituitary neuroendocrine tumor (PitNET). Acromegaly-causing tumors are histologically diverse. Our aim was to determine transcriptomic profiles of various somatotroph PitNETs and to evaluate clinical implication of differential gene expression. A total of 48 tumors were subjected to RNA sequencing, while expression of selected genes was assessed in 134 tumors with qRT-PCR. Whole-transcriptome analysis revealed three transcriptomic groups of somatotroph PitNETs. They differ in expression of numerous genes including those involved in growth hormone secretion and known prognostic genes. Transcriptomic subgroups can be distinguished by determining the expression of marker genes. Analysis of the entire cohort of patients confirmed differences between molecular subtypes of tumors. Transcriptomic group 1 includes ~20% of acromegaly patients with GNAS mutations-negative, mainly densely granulated tumors that co-express GIPR and NR5A1 (SF-1). SF-1 expression was verified with immunohistochemistry. Transcriptomic group 2 tumors are the most common (46%) and include mainly GNAS-mutated, densely granulated somatotroph and mixed PitNETs. They have a smaller size and express favorable prognosis-related genes. Transcriptomic group 3 includes predominantly sparsely granulated somatotroph PitNETs with low GNAS mutations frequency causing ~35% of acromegaly. Ghrelin signaling is implicated in their pathogenesis. They have an unfavorable gene expression profile and higher invasive growth rate.