Silent Tumors Research Articles

Machine learning-based ovarian cancer prediction with XGboost and stochastic gradient boosting models

Ovarian cancer is one of the most common types of gynecological malignancies with its high mortality rate, silent and occult tumor growth, late onset of symptoms and diagnosis in advanced stages. Therefore, the need to develop new diagnostic techniques to predict the course of the disease and the prognosis of this malignancy has increased. In this study, ovarian cancer and benign ovarian tumor samples will be classified to create an accurate diagnostic predictive model using the machine learning method XGBoost and Stochastic Gradient Boosting and disease-related risk factors will be determined. This current study considered the open-access ovarian cancer and benign ovarian tumor samples data set. For this purpose, data from 349 patients were included. The data set was divided as 80:20 as a training and test dataset. XGBoost and Stochastic Gradient Boosting were constructed for the classification via five-fold cross-validation. Accuracy, balanced accuracy, sensitivity, specificity, positive predictive value, and negative predictive value performance metrics were evaluated for model performance. Among the performance criteria in the test stage obtained from the XGBoost model that has the best classification result; accuracy, balanced accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and F1 score were obtained as 89.5%, 88.7%, 85.7%, 91.7%, 85.7%, 91.7%, and 85.7%, respectively. According to the variable importance obtained as a result of the model, the variables most associated with the diagnosis were CA72-4, HE4, LYM%, ALB, EO%, BUN, RBC, NEU, and MCV, respectively. The applied machine learning model successfully classified ovarian cancer and created a highly accurate diagnostic prediction model. The results from the study revealed effective parameters that can diagnose ovarian cancer with high accuracy. With the parameters determined as a result of the modeling, the clinician will be able to simplify and facilitate the decision-making process for the diagnosis of ovarian cancer.

Aggressive pituitary tumours and carcinomas, characteristics and management of 171 patients.

ObjectiveTo describe clinical and pathological characteristics and treatment outcomes in a large cohort of aggressive pituitary tumours (APT)/pituitary carcinomas (PC).DesignElectronic survey August 2020–May 2021.Results96% of 171 (121 APT, 50 PC), initially presented as macro/giant tumours, 6 were microadenomas (5 corticotroph). Ninety-seven tumours, initially considered clinically benign, demonstrated aggressive behaviour after 5.5 years (IQR: 2.8–12). Of the patients, 63% were men. Adrenocorticotrophic hormone (ACTH)-secreting tumours constituted 30% of the APT/PC, and the gonadotroph subtypes were under-represented. Five out of 13 silent corticotroph tumours and 2/6 silent somatotroph tumours became secreting. Metastases were observed after median 6.3 years (IQR 3.7–12.1) from diagnosis. At the first surgery, the Ki67 index was ≥3% in 74/93 (80%) and ≥10% in 38/93 (41%) tumours. An absolute increase of Ki67 ≥ 10% after median of 6 years from the first surgery occurred in 18/49 examined tumours. Tumours with an aggressive course from outset had higher Ki67, mitotic counts, and p53. Temozolomide treatment in 156/171 patients resulted in complete response in 9.6%, partial response in 30.1%, stable disease in 28.1%, and progressive disease in 32.2% of the patients. Treatment with bevacizumab, immune checkpoint inhibitors, and peptide receptor radionuclide therapy resulted in partial regression in 1/10, 1/6, and 3/11, respectively. Median survival in APT and PC was 17.2 and 11.3 years, respectively. Tumours with Ki67 ≥ 10% and ACTH-secretion were associated with worse prognosis.ConclusionAPT/PCs exhibit a wide and challenging spectrum of behaviour. Temozolomide is the first-line chemotherapy, and other oncological therapies are emerging. Treatment response continues to be difficult to predict with currently studied biomarkers.

Hemorrhagic presentation of previously silent brain tumors

Introduction and objectivesAcute presentation with intracranial hemorrhage owing to a previously silent brain tumor (BT) is rare. Although any BT can bleed, the frequency and type of bleeding varies across tumor types. Materials and methodsWe aimed to retrospectively review our experience with 55 patients with BTs presenting with ICH. ResultsSigns of increased intracranial pressure were the most common symptoms. The temporal lobe was the most common lesion site (n=22). Hemorrhages were mainly confined to the tumor margins (HCTs) (n=34). Extensive intraparenchymal hemorrhages (EIHs) were mainly associated with moderately/severely decreased levels of consciousness (LOCs) (n=15/16). High-grade glioma (HGGT) (n=25) was the leading pathological diagnosis followed by metastasis (MBT) (n=16/55). The hemorrhage type was associated with the pathological diagnosis of the tumor. Patients with HGGT (n=19/25) and MBT (n=9/16) mainly presented with HCTs, whereas low-grade gliomas (LGGT) primarily caused EIHs (n=6/7). ConclusionsHemorrhagic presentation is a rare occurrence in BTs. Among all, MBT and HGGT are responsible for majority of the cases. Importantly, despite their relatively benign characteristics, LGGTs mainly result in extensive parenchymal destruction once they bleed. Maximum surgical resection of hemorrhagic BTs and decompression of the affected brain regions followed by histological confirmation of the diagnosis should be the main goals of treatment in cases with hemorrhagic BTs.

Single-cell RNA sequencing in silent corticotroph tumors confirms impaired POMC processing and provides new insights into their invasive behavior.

Provide insights into the defective POMC processing and invasive behavior in silent pituitary corticotroph tumors. Single-cell RNAseq was used to compare the cellular makeup and transcriptome of silent and active corticotroph tumors. A series of transcripts related to hormone processing peptidases and genes involved in the structural organization of secretory vesicles were reduced in silent compared to active corticotroph tumors. Most relevant to their invasive behavior, silent corticotroph tumors exhibited several features of epithelial-to-mesenchymal transition, with increased expression of mesenchymal genes along with the loss of transcripts that regulate hormonal biogenesis and secretion. Silent corticotroph tumor vascular smooth muscle cell and pericyte stromal cell populations also exhibited plasticity in their mesenchymal features. Our findings provide novel insights into the mechanisms of impaired POMC processing and invasion in silent corticotroph tumors and suggest that a common transcriptional reprogramming mechanism simultaneously impairs POMC processing and activates tumor invasion.

Corticotroph pituitary carcinoma with skeletal metastases masquerading as ectopic ACTH syndrome: a long and winding road to diagnosis.

SummaryPituitary carcinoma is a rare type of malignancy and only accounts for 0.1–0.2% of all pituitary tumours. Most pituitary carcinomas are hormonally active and they are mostly represented by corticotroph and lactotroph carcinomas. Corticotroph carcinoma can present as symptomatic Cushing’s disease or can evolve from silent corticotroph adenoma which is not associated with clinical or biochemical evidence of hypercortisolism. We hereby present a case of a bone-metastasized corticotroph pituitary carcinoma masquerading as an ectopic adrenocorticotropic hormone (ACTH) syndrome in a patient with a history of a non-functioning pituitary macro-adenoma. Our patient underwent two transsphenoidal resections of the primary pituitary tumour followed by external beam radiation therapy. Under hydrocortisone substitution therapy she developed ACTH-dependent hypercortisolism without arguments for recurrence on pituitary MRI and without central-to-peripheral ACTH-gradient on inferior petrosal sinus sampling, both suggesting ectopic production. Ultimately, she was diagnosed with an ACTH-secreting vertebral metastasis originating from the primary pituitary tumour. This case report demonstrates the complex pathophysiology of pituitary carcinoma and the long diagnostic work-up. Certain features in pituitary adenoma should raise the suspicion of malignancy.Learning pointsThe diagnosis of pituitary carcinoma can only be made based on documented metastasis, therefore, due to the often long latency period between the detection of the primary tumour and the occurrence of metastasis, the diagnostic work-up most often spans over multiple years.Pituitary carcinoma including corticotroph carcinoma is very rare in contrast to pituitary adenoma and only accounts for 0.1–0.2% of all pituitary tumours.Histopathology in pituitary adenoma should certainly accomplish the following goals: accurate tumour subtyping and assessment of tumoural proliferative potential.Repeated recurrence of pituitary adenoma after surgical resection, a discrepancy between biochemical and radiological findings, resistance to medical and radiation therapy, and silent tumours becoming functional are all hallmarks of pituitary carcinoma.Silent corticotroph adenomas are non-functioning pituitary adenomas that arise from T-PIT lineage adenohypophyseal cells and that can express adrenocorticotropic hormone on immunohistochemistry, but are not associated with biochemical or clinical evidence of hypercortisolism. Silent corticotroph adenomas exhibit a more aggressive clinical behaviour than other non-functioning adenomas.Treatment options for corticotroph carcinoma include primary tumour resection, radiation therapy, medical therapy, and chemotherapy. Sometimes bilateral adrenalectomy is necessary to achieve sufficient control of the cortisol excess.

Abstract P4-04-05: Development of unique immune responses triggered by cryoablation of breast cancers

Abstract Background: Breast cancers are traditionally viewed as immunologically silent. However, recent research has demonstrated that the triple-negative breast cancer (TNBC) and HER-2 positive (HER2) are capable of stimulating the immune system. In contrast, the most commonly diagnosed subtype, the luminal A (hormone receptor positive (HR+)/HER-2 negative), is associated with a lower degree of tumor infiltrating lymphocytes (TILs) and low expression level of immune checkpoint regulators such as programmed death-ligand-1 (PD-L1). Cryoablation, the destruction of cells by ultra-low temperatures, has been used to treat benign breast disease and clinical trials have been conducted to determine its utility for invasive breast cancers. The primary endpoint has been the rate of complete tumor ablation with no assessment of immunological responses. We hypothesized that neoantigens released during cryoablation might be sufficient to trigger immune responses that could aid in the prevention/reduction of metastatic spread and relapse of breast cancers.In this pilot study we evaluated biopsy material, cryoablated specimens and sentinel lymph nodes (SLN) from patients enrolled in the ACOSOG Z1072 trial at Lankenau Medical Center (LMC) [N=18] with cancers < 2 cm. Responses were compared to patients treated with surgical resection.Methods: After obtaining IRB approval for retrospective analyses of specimens from the ACOSOG Z1072 trial, immunohistochemical staining of archival specimens was performed. An on-going biomarker study protocol was amended to include immune markers and used to select control patients of similar age and tumor characteristics. Per trial protocol, tumors had to be be surgically removed within 28 days of cryoablation, but the exact time was left to the surgeons discretion. Participating surgeons at LMC preferred to remove tumors on average 24.7 days after ablation resulting in an average time from diagnosis to surgical removal of 43.3 days (range 25- 56 days). Although most breast surgeries are performed within two weeks of diagnosis; some patients defer their surgery for personal reasons. This allowed us to identify patients (N=26) with a comparable average time from diagnosis to surgery of 37 days (range 21 - 66 days). Sections were stained for CD4, CD8, CD20, CD21, and CD1c to assess possible changes in immune repertoire due to cryoablation. We also evaluated presence of immune check-point regulators such as PD-L1 and CTLA-4 in biopsy, surgical material and SLN together with the immune modulator IDO1 using commercially available antibodies and standard techniques. Results: Cryoablation transformed tumors in patients into a gelatinous mass surrounded by a fibrotic capsule. The ACOSOG trial demonstrated an effective cryoablation-induced destruction of ER+ invasive ductal carcinoma lesions in 92% of patients (N=86). Sections from cryoablation patients displayed a necrotic core and infiltrating lymphocytes in the microenvironment. These masses had a slightly higher presence of CD8+ lymphocytes compared to CD4+. The inverse relation was observed in non-cryoblated specimens. SLNs from cryoablated patients had an elevated presence of CD20+ B cells compared to patients treated by surgery. Follicular dendritic cells (CD21+) were also present at higher numbers in SLNs from cryoablated patients. We detected positive staining for both PD-L1 and IDO1 among surgical and cryoablated patients. Sporadic presence of CTLA-4 was identified with a slight preference for cryoabalted patients. Conclusion: Cryoablation of breast cancer lesions can induce immune responses in vivo with possible anti-tumor activity in immunologically silent tumors such as HR+ breast cancers. All local cryo patients in the clinical trial are currently disease-free (F/U 5 - 13years), while 1 surgical patient is alive with late recurrence (11 years post-surgery). Citation Format: Margaretha Wallon, Jonah D Klein, Zachary Aukers, Nolan Metz, Vibha Ahudja, Laura Mandik-Nayak, Vincenzo Ciocca, Vlasta Zemba-Palko, Robin M Ciocca, Jennifer L Sabol, Ned Z Carp. Development of unique immune responses triggered by cryoablation of breast cancers [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-04-05.

Using chemotherapy against metastatic pancreatic neuroendocrine neoplasm: how aggressively do we treat it? Real world data from a Brazilian Cancer Center

INTRODUCTION: Pancreatic neuroendocrine neoplasms (pNEN) have poor prognosis. Available treatment options are limited. We aimed to evaluate the clinical characteristics and outcomes in patients with pNEN undergoing systemic chemotherapy. METHODS: Retrospective study of patients with metastatic pNEN diagnosed between January 2000 and April 2018 in A.C. Camargo Cancer Center. We evaluated epidemiological characteristics and outcomes of patients who received systemic chemotherapy between the first and third-lines. RESULTS: 35 patients with median age of 54.4 years; 51.4% had diabetes mellitus and 62.9% had smoking history. Most primary tumors were located in pancreatic body or tail and 34.3% were described as well or moderately differentiated, 40% were of high grade. Overall, chemotherapy from first to third-line was prescribed 50 times, 62% consisted of platin doublet, the chosen schema 50% of times when Ki-67<20%, 55.5% for Ki-67 between 20% and 55% and 66.7% for Ki-67>55%. The median PFS and RR were 7.8 months and 40.7%; 13 months and 33.3% and 3 months and 0% in the first, second and third-line, respectively. The estimated OS was 53.4 months. We found that female (HR 2.8, p=0.034), DM (HR 4.5, p=0.004), smoking (HR 3.5, p=0.017), high grade tumors (HR 3.8, p=0.025) and tumors localized in head/neck of the pancreas (HR 7.1, p<0.001) were negative prognostic factors for OS in univariate analysis. CONCLUSION: Our real world data shows that doublet platin is a preferred and active schema for treating pNEN, especially in first and second line. It brings the greatest benefit for undifferentiated tumors. Nevertheless, the prognosis remains poor and some factors may contribute to worse outcomes, such as female gender, silent tumors that do not manifest DM, poorly differentiated tumours, smoking and location in the head and neck of the pancreas.

Abstract P031: Enrichment of photodynamically-primed anti-tumor immune infiltrates in pancreatic cancer: Enabling enhanced immunotherapy

Abstract Pancreatic ductal adenocarcinoma (PDAC) has a dismal 5-year survival rate of 10%. It poorly responds to conventional cancer treatments. Immune checkpoint blockade (ICB) has revolutionized cancer therapeutics. However, in PDAC, even the modest success of ICB is limited to ~1-3% of patients as the majority of patients' tumors are considered as immunologically ‘'cold'' due to their highly immunosuppressive tumor microenvironment (TME). Photodynamic therapy (PDT) is an FDA approved anti-cancer therapy that utilizes light, a photoresponsive non-toxic chemical called a photosensitizer, and oxygen to generate reactive molecular species that confer direct cytotoxicity or vascular shutdown. PDT alters the TME transiently in a process termed photodynamic priming (PDP), making it more receptive to subsequent therapies, including chemo- and immunotherapy. Previous studies have demonstrated that PDP is capable of affecting both the innate and adaptive immune systems. These immune-stimulatory effects occur through its ability to induce immunogenic cell death via the release of damage-associated molecules (DAMPs) and tumor-associated antigens. In this study, we investigated PDP-induced immunogenicity in PDAC. In an immunocompetent mouse model of PDAC, we evaluated tumor-infiltrating lymphocyte (TIL) enrichment in tumors and ongoing immune responses in mouse spleens/blood from 1h to 120h post-PDP treatment comparing the responses in untreated controls. We observed gradual increases in T and B cell infiltration from 1h to 120h post-PDP where the T cell subset analysis showed an enrichment of CD8+ T cells in PDP-treated tumors. These CD8+ T cells showed temporal increases in PD1, CTLA4 and TIM3 immune checkpoints suggesting PDP-induced immune priming in the TME. This was further evidenced by the upregulation of DAMPs, including high mobility group box protein-1 and calreticulin in PDP treated tumors. Analyzing spleens of mice, we detected a significant increase in CD11C+MHC11hi dendritic cells from 1h to 24h post-PDP. Also, activation of an adaptive immune response in splenic B cell follicles was noted by the presence of proliferating germinal centers by 120h post-PDP. In addition, evaluating the blood of PDP treated mice, we detected expansion of CD8+ effector memory T and natural killer cell populations, signifying PDP-induced systemic immune responses compared to untreated mice. We further investigated how immune cells infiltrate PDP-treated tumors. A reduced formation of blood (CD31+) and lymphatic (Lyve-1+) vessels post-PDP at 120h was observed. However, decreases in PDL1, collagen and fibroblast activation proteins were observed in PDP-treated tumors at 120h, suggesting mitigation of immunosuppressive mechanisms and enhanced tumor permeability, allowing TIL migration. Our data shows converting immunologically silent PDAC tumors into inflamed ‘'hot'' tumors by triggering not only a local immune infiltration but also enhanced systemic immune responses, ultimately enhances the immunogenicity of pancreatic tumors. Citation Format: Pushpamali De Silva, Mohammad Ahsan Saad, Zhiming Mai, Shazia Bano, Assiris P. Camargo, Tayyaba Hasan. Enrichment of photodynamically-primed anti-tumor immune infiltrates in pancreatic cancer: Enabling enhanced immunotherapy [abstract]. In: Abstracts: AACR Virtual Special Conference: Tumor Immunology and Immunotherapy; 2021 Oct 5-6. Philadelphia (PA): AACR; Cancer Immunol Res 2022;10(1 Suppl):Abstract nr P031.

PROGNOSTIC ROLE OF THE PRIMARY TREATMENT IN THE NATURAL HISTORY OF OVARIAN CANCER: A PILOT STUDY

Epithelial Ovarian cancer is the most lethal and silent gynaecological tumor and relapses in about 75% of cases. Retrospective data supported the superiority of secondary cytoreduction surgery (SCS) plus chemotherapy versus chemotherapy alone; in order to best select patients for SCS literature established a clinical score based on ascites, performance status, and absence of … Continued

Detection of clinically silent brain lesions in [18F]FDG PET/CT study in oncological patients: analysis of over 10,000 studies

The study aimed to show that including the brain region into the standard 2-deoxy-2-[18F]fluoro-d-glucose positron emission tomography/computed tomography ([18F]FDG PET/CT) study protocol may result in detecting clinically silent brain tumours. We retrospectively analyzed the group of 10,378 from the total of 12,011 consecutive patients who underwent the torso and brain [18F]FDG PET/CT scanning, considering an ability of the method to evaluate undetected before brain tumours in patients diagnosed and treated in our institution. While collecting the database, we followed the inclusion criteria: at least 1-year of follow-up, a full medical history collected in our institution, histopathologic examination or other studies available to confirm the type of observed lesion, and the most importantly—no brain lesions reported in the patients’ medical data. In this study, performing the torso and brain [18F]FDG PET/CT imaging helped to detect clinically silent primary and metastatic brain tumours in 129 patients, and the benign lesions in 24 studied cases, in whom no suspicious brain findings were reported prior to the examination. In conclusion, including the brain region into the standard [18F]FDG PET/CT protocol can be considered helpful in detecting clinically silent malignant and benign brain tumours.

Gut Microbiota Dynamics during Chemotherapy in Epithelial Ovarian Cancer Patients Are Related to Therapeutic Outcome.

Simple SummaryThis pilot study on the trajectory of the gut microbiota (GM) in patients with epithelial ovarian cancer undergoing neoadjuvant and adjuvant chemotherapy highlighted peculiar dynamics associated with the therapeutic outcome. In particular, platinum-resistant patients showed a marked temporal reduction in GM diversity and increased instability with loss of health-associated taxa and increased proportions of lactate-producing microorganisms compared to those sensitive to platinum. These potential GM signatures of therapeutic failure are detectable within the first half of chemotherapy cycles, suggesting that early integrated treatments also aimed at modulating GM could influence therapeutic outcome. Further studies in larger cohorts combining multiple omics and possibly animal models are urgently needed for in-depth mechanistic understanding.Epithelial ovarian cancer (EOC) is one of the most lethal and silent gynecological tumors. Despite appropriate surgery and chemotherapy, relapse occurs in over half of patients with a poor prognosis. Recently, the gut microbiota (GM) was hypothesized to influence the efficacy of anticancer therapies, but no data are available in EOC. Here, by 16S rRNA gene sequencing and inferred metagenomics, we profiled the GM of EOC patients at diagnosis and reconstructed its trajectory along the course of neoadjuvant or adjuvant chemotherapy up to follow-up. Compared to healthy subjects, the GM of EOC patients appeared unbalanced and severely affected by chemotherapy. Strikingly, discriminating patterns were identified in relation to the therapeutic response. Platinum-resistant patients showed a marked temporal reduction in GM diversity and increased instability with loss of health-associated taxa and increased proportions of Coriobacteriaceae and Bifidobacterium. Notably, most of these microorganisms are lactate producers, suggesting increased lactate production as supported by inferred metagenomics. In contrast, the GM of platinum-sensitive patients appeared overall more diverse and stable and enriched in lactate utilizers from the Veillonellaceae family. In conclusion, we identified potential GM signatures of therapeutic outcome in EOC patients, which could open up new opportunities for cancer prognosis and treatment.

Retroperitoneal pheochromocytoma: Unsual presentation and atypical location.

Introduction and importancePheochromocytomas are rare tumors (0.1–2% of incidence), arising from the chromaffin cells in the sympathoadrenal system. Approximately 85% of the times are localized in the adrenal medulla; therefore, could be placed extra adrenal in 15% of the population. 10–30% of the cases could be asymptomatic. Classic symptoms vary from palpitations, tachycardia, hypertension.Case presentationCase report of a 37-year-old female patient presented with diffuse abdominal pain, with any associated symptoms. Contrast computed tomography was performed; a retroperitoneal mass was found, contacting the third portion of the duodenum. Intraoperative hypertensive crisis was documented with the manipulation of the mass. Octreotide infusion was administered with the normalization of the clinical condition. Patients do not present any postoperative morbidity after 90 days. Pathology reports chromaffin cells concluding pheochromocytoma.DiscussionPheochromocytomas are rare tumors with an annual incidence between 3 and 8 cases per million population per year in some series of cases. In general terms prevalence rounds 0.1–0.6% of patients with hypertension. Surgical management is the definitive treatment for pheochromocytoma benign or malign. Morbidity described in literature reaches 40% with 20% of mortality in some series of cases. In our patient we do not present postoperative complications.ConclusionIntraoperative hypertension is a clinical and surgical challenge, not only for the surgeon, also anesthesiology. Pheochromocytoma it's a complex entity and could be silent in until 30% of the cases, should be suspected in all neuroendocrine retroperitoneal tumors. Multidisciplinary approach with anesthesia, endocrinology and surgery department is mandatory to have good postoperative outcomes.

Primary and Metastatic Brain Tumours Assessed with the Brain and Torso [18F]FDG PET/CT Study Protocol-10 Years of Single-Institutional Experiences.

According to the international societies’ recommendations, the 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography/computed tomography ([18F]FDG PET/CT) technique should not be used as the method of choice in brain tumour diagnosis. Therefore, the brain region can be omitted during standard [18F]FDG PET/CT scanning. We performed comprehensive literature research and analysed results from 14,222 brain and torso [18F]FDG PET/CT studies collected in 2010–2020. We found 131 clinically silent primary and metastatic brain tumours and 24 benign lesions. We concluded that the brain and torso [18F]FDG PET/CT study provides valuable data that may support therapeutic management by detecting clinically silent primary and metastatic brain tumours.

Abstract LB134: The rexinoid MSU-42011 enhances dendritic-T cell cross talk in a HER2 positive model of breast cancer

Abstract Breast cancer (BC) was considered an immunologically silent tumor, however recent findings suggest that immune cells present in the tumor microenvironment play important roles in tumor growth. Retinoid X receptors (RXRs) are a subclass of nuclear receptors that act as ligand-dependent transcription factors that regulate a variety of cellular processes including proliferation and differentiation. Rexinoids are synthetic molecules that bind and activate RXRs. Bexarotene (Targretin®) is the only rexinoid approved by the FDA and is used for the treatment of refractory cutaneous T-cell lymphoma. Other more potent rexinoids have been synthesized, such as LG100268 and LG101506, which will not be tested in clinical trials because of intellectual property issues. Because recent studies have suggested that RXRs are involved in immune regulation, we synthesized novel rexinoids and selected MSU-42011 as a lead compound. MMTV-neu mice with tumors approximately 32 mm3 in volume were treated with control diet or MSU-42011 (100 mg/kg diet) for 10 days. Rexinoid treatment significantly (p=0.0069) reduced tumor fold change normalized to initial volume from 8.33 in controls to 4.80 on treatment. Analysis of the tumor by flow cytometry showed no significant differences in the major immune populations, such as T cells, macrophages and dendritic cells. However, expression of PDL1 was increased in CD11c+, MHC-II+ dendritic cells (5484 vs 7140 MFI, p=0.0456), suggesting engaged dendritic cells in activating cytotoxic T cells. To further elucidate the cross talk between dendritic and T cells, cytokines associated with T cell recruitment and activation were analyzed by RT-PCR. Tumor treated with MSU42011 had a 38.5 fold increase in IL12a expression (p=0.011, n=4), and a 20.8 fold increase in CCL9 (p=ns, n=4), suggesting that dendritic cells are actively recruiting and activating T cells. The activation of cytotoxic T cells was confirmed by a 75.5 fold increase in interferon gamma (p=0.0026, n=4) and a decrease of FOXP3 expression (p=ns, n=4). To test if the effects seen in tumor reduction were dependent on the presence of T cells, CD4 and CD8 were depleted. Depletion of CD4 alone, but not CD8, reversed the tumor reduction induced by MSU-42011. These results show that RXR agonists can be used to modulate immune cell populations in the tumor microenvironment, specifically by recruiting and activating dendritic cells that then activate cytotoxic T cells. We thank the Breast Cancer Research Foundation for support of these studies. Citation Format: Ana Sofia Leal, Sarah Carapellucci, Karen T. Liby. The rexinoid MSU-42011 enhances dendritic-T cell cross talk in a HER2 positive model of breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB134.

Clinical, Biological, Radiological Pathological and Immediate Post-Operative Remission of Sparsely and Densely Granulated Corticotroph Pituitary Tumors: A Retrospective Study of a Cohort of 277 Patients With Cushing's Disease.

PurposeCushing’s disease is the most common cause of endogenous hypercortisolemia due to a corticotroph pituitary tumor. Up-to-date there is no reliable biomarker of invasiveness among corticotroph tumors, while it is well established in the literature that sparsely granulated somatotroph tumors are characterized by poorer prognosis. The aim of the study was to correlate multiple data including clinical, biochemical, radiological, and pathological findings (including granulation pattern) as well as immediate post-operative remission status among patients operated on due to corticotroph tumors.MethodsWe enrolled all patients consecutively operated on for planned transsphenoidal neurosurgery due to corticotroph PitNETs in years 2010–2018. We excluded from analysis silent corticotroph tumors, plurihormonal PitNETs, and the Crooke’s cell adenomas.ResultsWe recorded 348 hormonally active corticotroph PitNETs. The results of the analysis showed the female predominance 79.88% (n = 278), with the mean age of Cushing’s disease occurrence 43.27 years of age. The mean time from the first signs and symptoms to the operation was 2 years. The women were diagnosed earlier (20–40 years of age vs. 50–60 years of age among men). We performed a detailed analysis of 277 cases classified by granularity pattern as DG or SG corticotroph PitNETs. Densely granulated tumors (DG) occurred four times more frequently than sparsely granulated (SG) (n = 225 vs. n = 52), at similar age (mean 42.94; median 40 vs. mean 45.46; median 45.5; p = 0.3896), but were characterized by lower Knosp’s scale grades (p = 0.0147*), smaller preoperative tumors’ volumes measured at MRI, and more commonly exhibited lower Ki-67 labeling index (<3%) (p = 0.0168*). What is more, DG adenomas more frequently achieved an immediate remission status (measured as postoperative cortisol concentration <2 µg/dl; p = 0.0180*), and the mean postoperative cortisol concentration in DG group was lower than in SG group (mean 5.375 µg/dl vs. 10.47 µg/dl; median 2.49 µg/dl vs. 6.52 µg/dl; p = 0.0028**).ConclusionsOur study indicates that DG corticotroph adenomas occurred at younger age, more commonly were microadenomas as compared to SG tumors, less frequently had invasive features in comparison to SG corticotroph adenomas (p = 0.0019**), and more commonly achieved an immediate postsurgical hormonal remission (p = 0.0180*). We highlight the need for an accurate differentiation of DG and SG subtypes in the pathomorphological diagnosis of corticotropic tumors, especially in invasive PitNETs.

Genetic Variants in Patients with Multiple Head and Neck Paragangliomas: Dilemma in Management

Multiple head and neck paragangliomas (HNPGLs) are neuroendocrine tumors of a mostly benign nature that can be associated with a syndrome, precipitated by the presence of a germline mutation. Familial forms of the disease are usually seen with mutations of SDHx genes, especially the SDHD gene. SDHB mutations are predisposed to malignant tumors. We found 6 patients with multiple tumors amongst 30 patients with HNPGLs during the period of 2016 to 2021. We discuss the phenotypic and genetic patterns in our patients with multiple HNPGLs and explore the management possibilities related to the disease. Fifty percent of our patients had incidental findings of HNPGLs. Twenty-one biochemically silent tumors were found. Four patients had germline mutations, and only one had a positive family history. Three out of five underwent surgery without permanent complications. Preventative measures (genetic counselling and tumor surveillance) represent the gold standard in effectively controlling the disease in index patients and their relatives. In terms of treatment, apart from surgical and radiotherapeutic interventions, new therapeutic measures such as gene targeted therapy have contributed very sparsely. With the lack of standardized protocols, management of patients with multiple HNPGLs still remains very challenging, especially in those with sporadic or malignant forms of the disease.

New Transcriptional Insights into Silent and Active Corticotroph Pituitary Tumors at Single Cell Resolution

Silent pituitary corticotroph tumors derive from the Tpit (aka TBX19) pituitary lineage. Accounting for ~ 30% of corticotroph tumors, they are not infrequently clinically aggressive and invade locally into adjacent sellar structures, making complete surgical resection challenging and contributing to their higher recurrence rates. How silent and active corticotroph tumor subtypes differ is not clear although some studies reported that silent corticotroph tumors exhibit reduced PC1 expression causing impaired POMC processing. We used single cell RNAseq to compare the transcriptome between silent (n = 2) and active (n = 4) corticotroph tumors at the single cell level. We obtained an average of 265 million reads, and 24,682 genes per patient with an average of 1,240 genes expressed and 3,5442 unique molecular identifiers (UMIs) detected per cell. We further defined 5 distinct cell populations from a total of 23,269 cells, namely tumor cells (62%), stromal cells (25%), immune cells (7%), progenitor cells (5%), and a minor population of erythrocytes (1%). Tumor cells clustered in an origin-dependent manner and all expressed POMC and TBX19. However, the gene signatures of silent and active corticotroph tumors differed in 3 major aspects. Firstly, and supporting prior studies, a series of hormone processing peptidase genes, including PC1 (aka PCSK1), PDIA3, SEC11C, SPCS1 and CTSB, were reduced in silent corticotroph tumors (p=5.54e-5) compared to active corticotroph tumors. Secondly, genes involved in organization of secretory vesicles such as SCG5, TIMP1, VGF, SYT17, LGALS3 and CALY were also reduced in silent corticotroph tumors, which could further compound their inability to secrete ACTH. Thirdly, the silent corticotroph tumors exhibited several features of endothelial-to-mesenchymal transition (EMT), including increased expression of the mesenchymal genes CDH2 (aka NCAD), COL1A1, PCDH9, FGF5, ID2 (p=8.4e-3), and loss of EPCAM, which regulate cell migration and movement. Upstream analysis suggested that aberrant STAT3 activation may be related to these changes. Consequently, we noted that the stromal content was higher in silent corticotroph tumors (47.5% vs. 18.13%), concordant with the observed EMT de-differentiation of tumor cells. In summary, our scRNAseq analysis provides an unprecedented precise investigation of the transcriptomic features of thousands of heterogenous corticotroph tumor cells simultaneously. We demonstrate that although silent corticotroph tumor cells still express the pituitary lineage markers PITX1 and TBX19, they exhibit EMT, potentially affording increased migratory capacity at the cost of reduced neuroendocrine function with inability to produce and secrete mature ACTH. Our findings provide novel insights into the pathogenesis of silent versus active corticotroph tumor, but may reveal novel molecular targets for treatment of these challenging tumors.

Double Trouble: A Challenging Case of Synchronous Catecholamine-Secreting Neck Paraganglioma and Pheochromocytoma

Abstract Background: Sympathetic paragangliomas (PGL) are regarded as catecholamine-secreting, extra-adrenal counterparts of pheochromocytomas (PCC). Hormone producing head and neck PGL (HNPGL) are exceedingly rare, as most HNPGL are biochemically silent parasympathetic tumors. Here, we present a case of synchronous sympathetic cervical PGL and PCC. Clinical Case: A 47-year-old male was referred to the Neuroendocrine Tumor Unit clinic after a failed attempt at PGL removal at another center. The patient had a 10-year history of hypertension and a family history of his mother’s sudden death. Prior to referral, he presented with a palpable 6 cm right neck mass - an uneventful core-needle biopsy pathology revealed PGL. Subsequent workup showed profoundly elevated plasma metanephrine (MN) 3000 pg/ml [&amp;lt;65] and normetanephrine (NMN) 3500 pg/ml [&amp;lt;196]. Following a week of 2 mg/d doxazosin therapy, an attempt to operate on the patient for PGL was aborted after the skin incision over the mass due to an intraoperative hypertensive crisis. Upon arrival to our unit, reassessment disclosed a sustained stage 3 hypertension that required a four antihypertensive drug regimen with doxazosin dose titration up to 16 mg/d. MRI showed a 6 cm well-defined mass that displaced the common carotid artery and internal jugular vein (IJV) anteromedially, consistent with a PGL of sympathetic chain origin. MRA identified no tumor feeding vessels that could be suitable for embolization. Ga68 DOTATATE PET/CT showed a single focus of radiotracer uptake in the right neck PGL; however, the CT did image a 1.3 cm right adrenal mass with radiographic features suggestive of PCC. The patient underwent surgery for the PGL, using vigilant intraoperative hemodynamic and upper cranial nerve monitoring. An extreme hypertensive episode (systolic BP 340 mmHg) early on during the tumor’s dissection was resolved once the venous connection between the PGL and the IJV was divided. Pathology revealed a 6 cm PGL with free surgical margins. Postoperatively, hormone levels dropped significantly (MN 98 pg/ml [&amp;lt;65]; NMT 198 pg/ml [&amp;lt;196]). Subsequently, right adrenalectomy was performed, confirming the diagnosis of a 1.6 cm PCC. At the last follow-up, the patient’s hypertension was controlled on 5 mg/d amlodipine. Plasma MN and NMN levels were normal. Genetic analysis for PGL/PCC-associated genes revealed no germline mutation. Conclusion: This case highlights the importance of preoperative workup and perioperative management of large PGL. Head and neck PGL resection may be challenging depending on tumor size and location. Early division of the venous outflow from the PGL into the IJV plays a crucial role in intraoperative hemodynamic control. A multidisciplinary team at experienced centers must be involved in every aspect of the patient’s care to achieve optimal results.

Desmopressin Test in Silent Corticothoph Pituitary Adenomas, a Preliminary Study - a Comparison With Cushing Disease

Introduction: Silent corticothop adenomas (SCAs) account for 9 to 19% of nonfunctioning pituitary adenomas and behave as the most agressive pituitary tumors with more invasiveness and high recurrence rate. The identification of these patients during the preoperative stage could predict better surgery results. Some authors refer to high basal ACTH level in the preoperative evaluation as the only marker but until this date, there are no clinical and hormonal markers that could predict its occurrence. The aim of this study is to evaluate the response to desmopressin test and the presence of silent corticothoph tumors. Patients and Methods: Among 496 patients underwent pituitary surgery, 425 were pituitary adenomas, (106 were acromegaly, 46 Cushing disease, 10 prolactinomas, 263 nonfunctioning adenomas). Twenty-three patients, 17 with Cushing disease, (CD), mean age: 31 y, 13 female and 4 male) and 6 patients with SCA (mean age: 47 y, 5 female and 1 male) had positive ACTH confirmed by immunohistochemical analysis. Clinical characteristics: in the CD group, 53% had hypertension (9/17), 42% diabetes (7/17), 100% dyslipidemia, BMI was 30.7 kg/m2. Among SCA group, 67% hypertension, 50% diabetes, 50% dyslipidemia, BMI was 28 kg/m2. All patients were evaluated with basal ACTH and DHEAS before surgery. Patients with SCA underwent desmopressin test and were compared to CD. Dexamethasone suppression test (DST 1 mg) and 24-hour free urinary test was performed in patients with CD and in two patients with SCA. Response to desmopressin test was considered positive when increase in cortisol was above 20% and in ACTH of 35% using chemiluminescence assay (Immulite 2000). Results: Among CD group, the median (med) basal ACTH was 75.9 pg/mL (30.9 to 211), the med basal cortisol was 22.5 µg/dL (14.5 to 43.5), the med DHEAS was 170 µg/dL (33 to 465), the med 24h urinary free cortisol of 454.5 µg/24 h (149 to 1673) and med basal cortisol after DST 1mg of 15.4 µg/dL (4.7 to 31.5). Among SCA, med basal ACTH was 19.4 pg/mL (9.5 to 65.5), the med basal cortisol was 9.5 µg/dL (7.8 to 16.4) and the med DHEAS was 104.5 µg/dL (82 to 127). Only 4 patients with CD had macroadenomas. All of them responded with ACTH increase (med increase of 98%, 31.6 to 377%), and only 4 did not respond to cortisol increase (med increase of 54.4%, 0 to 167%). All patients with SCA had macroadenomas. Only one patient did not respond to ACTH increase (med increase of 123.5%, 9.5 to 1522%, 9.5 to 1522%), and 3 patients did not respond to cortisol increase (med increase of 17.9%, 0 to 234%). Discussion: SCA are invasive tumors, with high recurrence and tests predicting their occurrence are missing. We hypothesized that as ACTH is present in the adenoma a response to desmopressin test could exist (like CRH). Conclusion:The desmopressin test can be a useful tool in the evaluation of SCA and can predict pathological phenotype in preoperative tumors.

Apoplexy of Crooke cell tumour leading to the diagnosis of severe Cushing disease; a case report

BackgroundPatients with Crooke cell tumours present with features of Cushing syndrome or mass effect. There are few reports of patients with Crooke cell tumours presenting due to apoplexy. All of them had silent tumours. Patients with Cushing syndrome caused by Crooke cell tumours have not been reported to present with apoplexy.Case presentationA 35-year-old female presented with sudden onset headache and visual loss for 1 week. She had secondary amenorrhoea for 10 years. There were features of Cushing syndrome including central obesity, multiple monomorphic acne, dorso-cervical and supraclavicular fat pads, hypertension, proximal weakness, pigmentation and refractory hypokalaemia. She was found to have markedly elevated serum cortisol, central hypothyroidism and hypogonadotropic hypogonadism. There was a mass in the sellar region (4.7 cm × 1.9 cm × 5.3 cm) suggestive of a pituitary tumour extending to the suprasellar region. Imaging showed evidence of bleeding and compression of the optic chiasm. She underwent urgent trans-sphenoidal excision of the tumour. Histology was compatible with a pituitary neuroendocrine tumour. There was margination of ACTH reactivity to the cell periphery and ring like positivity in most of the cells in the cytokeratin stain. Features were in favour of a Crooke cell tumour. After surgery she improved gradually and became eucortisolaemic.ConclusionsThis is a unique presentation of an apoplexy of Crooke cell tumour causing Cushing syndrome. Delayed health seeking behaviour of this patient despite severe Cushing disease could have led to this presentation which has not been reported before.