Combination Chemotherapy Research Articles

P01.15.A SURGICAL RESECTION-INDUCED ISCHEMIA DRIVES GLIOBLASTOMA CELL PLASTICITY AND TUMOR MICROENVIRONMENT ADAPTATION

Abstract BACKGROUND Glioblastoma IDH-wildtype (GBM) treatment involves a combination of surgical resection, radiation therapy, and chemotherapy with temozolomide. Despite the aggressive standard of care, 90% of patients experience recurrence a few months after treatment, typically marked by the regrowth of highly invasive cells spreading from the peritumoral brain resection zone. The impact of chemoradiotherapy has been studied, but the impact of microsurgical resection on the tumor microenvironment (TME) and the plasticity of GBM cells remains unknown. Hence, the objective of this work was to study histopathological and transcriptomic changes induced by microsurgical resection on residual tumor cells and TME. MATERIAL AND METHODS Syngeneic GBM cell lines CT2A and GL261 were orthotopically implanted in C57Bl6j mice brains meanwhile P3 xenografts were injected in immunosuppressed nude mice. We developed an optimized microsurgical resection protocol for GBM in mice, mirroring the steps performed in patients. In a size-matched study, mice were randomly assigned to four groups: control (pre-surgery) and 1, 3, and 7 days post-surgery. Tumor tissues were studied with a multilevel strategy composed of time-resolved bulk and single-cell RNA sequencing, immunohistochemistry and intravital multiphoton microscopy (IVM). RESULTS Our analyses showed that microsurgical resection induced pronounced proneural-to-mesenchymal transition (PMT) and stimulation of hypoxia-driven pathways in residual GB cells. Further, we detected significant changes in the TME relative to the immune response and vascular function in line with ischemia exposure, which could humper the response to treatment by altering the adequate effect and distribution of the subsequent chemoradiotherapy. CONCLUSION Microsurgical resection consequences play a crucial role in shaping the phenotypic landscape of GBM tumor cells and the TME, marked by a transient ischemic TME triggering PMT in GBM cells and potentially preventing the effective response to chemoradiotherapy.

NIR-II Fluorescent Nanotheranostics with a Switchable Irradiation Mode for Immunogenic Sonodynamic Therapy.

Nanotheranostics, which integrate diagnostic and therapeutic functionalities, offer significant potential for tumor treatment. However, current nanotheranostic systems typically involve multiple molecules, each providing a singular diagnostic or therapeutic function, leading to challenges such as complex structural composition, poor targeting efficiency, lack of spatiotemporal control, and dependence on a single therapeutic modality. This study introduces NPRBOXA, a nanoparticle functionalized with surface-bound cRGD for targeted delivery to αvβ3/αvβ5 receptors on tumor cells, achieving theranostic integration by sequentially switching its irradiation modes. Under 808nm laser irradiation, NPRBOXA emits NIR-II fluorescence, which aids in identifying the nanoparticle's location and fluorescence intensity, thereby determining the optimal treatment window. Following this, the irradiation mode switches to ultrasound irradiation at the optimal treatment window. Ultrasound irradiation induces NPRBOXA to generate reactive oxygen species, promoting the reduction of OXA-IV to OXA-II, which in turn triggers immunogenic cell death. This mechanism enables a combination of sonodynamic therapy, chemotherapy, and immunotherapy for tumor treatment. The versatile design of NPRBOXA holds promise for advancing precision oncology through enhanced therapeutic efficacy and real-time imaging guidance.

Plasmomagnetic hybrid gold nanostructures as multifunctional nanocarriers for drug delivery, MRI contrast, and photothermal therapy of drug-resistant cancer cells

Presenting a simple efficient method, plasmomagnetic hybrid nanostructures (PNIPAM coated gold nanorods-dexpion hybrid nanostructure, PN-GDHNs) capable of serving as dual drug nanocarriers, MRI contrast, and photothermal agents for cancer therapy were synthesized. The cisplatin (CDDP) and doxorubicin (DOX) were loaded on PN-GDHNs and tested for their drug release, cytotoxicity, photothermal, and MRI contrast in vitro. We found that the drug release was controlled by pH and temperature, and the cytotoxicity was enhanced by the combination of chemotherapy and photothermal therapy. We also found that the PN-GDHNs could overcome the drug resistance of MCF7 breast cancer cells and improve the MRI contrast. We achieved a high cancer cell-killing efficiency of 97.3 ± 0.4 % in one dose with low drug concentration and laser power. Our results suggest that PN-GDHNs are promising multifunctional nanocarriers for cancer therapy applications.

Nanoplatelets modified with RVG for targeted delivery of miR-375 and temozolomide to enhance gliomas therapy

Gliomas are one of the most frequent primary brain tumors and pose a serious threat to people’s lives and health. Platelets, a crucial component of blood, have been applied as drug delivery carriers for disease diagnosis and treatment. In this study, we designed engineered nanoplatelets for targeted delivery of therapeutic miR-375 and temozolomide (TMZ, a first-line glioma treatment agent) to enhance glioma therapy. Nanoplatelets were prepared through mild ultrasound, TMZ and miR-375 were co-loaded through ultrasound and electrostatic interactions, respectively, to combine chemotherapy with gene therapy against glioma. To improve the blood brain barrier (BBB) crossing efficiency and glioma targeting ability, the nanoplatelets were modified with central nervous system-specific rabies viral glycoprotein peptide (RVG) through thiol-maleimide click reaction. The RVG modified nanoplatelets co-loaded TMZ and miR-375 (NR/TMZ/miR-375) not only inherited the good stability and remarkable biocompatibility of platelets, but also promoted the cellular uptake and penetration of glioma tissues, and effectively induced cell apoptosis to enhance the therapeutic effect of drugs. In vivo studies showed that NR/TMZ/miR-375 significantly increased the circulation time of TMZ, and exhibited superior combined antitumor effects. In summary, this multifunctional ‘natural’ nanodrug delivery system provides a potent, scalable, and safety approach for platelet-based combined cancer chemotherapy and gene therapy.

Co-existence of Myelodysplastic Disorders and Plasma Cell Neoplasms: Case Series

Abstract Introduction/Objective The development of myelodysplastic syndrome (MDS) in patients with plasma cell neoplasm (PCN) receiving treatment is well reported. However, co-occurrence of both, without any chemotherapy history, is sparsely documented in the literature. We aim to highlight the possible association between both. Methods/Case Report Database search was done using Epic Slicer-Dicer for cases with biopsy proven co-existing MDS and PCN (from 2010-2022). The patients’ charts were reviewed to collect and analyze the clinical features. Results (if a Case Study enter NA) We identified 3 patients, all in their seventies on presentation: First patient: man, presented with unexplained chronic anemia. Serum protein electrophoresis (SPEP) showed elevated levels of monoclonal IgG kappa (4.2 g/dl). Evaluation of the BM biopsy revealed MDS with low blasts (WHO-5) with IgG plasma cell myeloma (56% Kappa-restricted plasma cells). Chromosome analysis revealed normal karyotype. Molecular studies were not done. Second patient: man, with Rheumatoid Arthritis and anemia. SPEP revealed biclonal IgG lambda (2.0 g/dl). BM biopsy indicated 5-8% lambda-restricted plasma cell proliferation. Anemia was managed with darbopoetin, but without improvement. The patient did not get chemotherapy. Follow-up BM biopsy was done, showing MDS with low blasts and ringed sideroblasts (WHO-5) alongside the PCN. FISH showed two abnormal IGH rearrangement populations. Chromosome analysis revealed normal karyotype. Molecular studies were not done. Third patient: woman, with pancytopenia. SPEP indicated monoclonal protein IgG lambda (1.8 g/dl). BM biopsy revealed 10% lambda-restricted plasma cell proliferation, coexisting with MDS with increased blasts grade 2 (WHO-5). Molecular studies showed: 2-FLT3 L601_K602insNFREYEYDL and ASXL1 E635fs*15. Chromosome analysis revealed normal karyotype. No in common clinical findings found during chart reviewing the cases. Conclusion Further investigating the underlying pathology, bone marrow microenvironment, and molecular and cytogenetics abnormalities in a larger number of patients with co-existing MDS and PCN is important. Also, if there was an association, it is important to study the sequence of occurrence between them.

Histidine phosphatase-ferroptosis crosstalk modulation for efficient hepatocellular carcinoma treatment

Altering the mechanisms of tumor cell death and overcoming the limitations of traditional chemotherapy is pivotal to contemporary tumor treatment. Inducing ferroptosis, while circumventing safety concerns associated with ferrous vectors, through nonferrous ferroptosis is a promising but underexplored frontier in cancer therapy. Histidine phosphatase (LHPP) has emerged as a novel therapeutic target in treating hepatocellular carcinoma (HCC), but the precise mechanism of LHPP against HCC remains unclear. Herein, we explore the effects of upregulating LHPP expression on ferroptosis and tumor immunogenicity induction by simply delivering a miRNA-363-5p inhibitor (miR-363-5pi) via a previously optimized gemcitabine-oleic acid (GOA) prodrug. Efficient miRNA encapsulation was achieved through hydrogen bonding at an optimized GOA/miRNA molar feed ratio of 250:1, affording spherical nanoparticles with a uniform hydrodynamic size of 147.1 nm and a negative potential of -21.5 mV. The mechanism of this LHPP-ferroptosis crosstalk is disclosed to be an inhibited phosphorylation of the PI3K/Akt pathway, leading to a remarkable tumor inhibition rate of 88.2% in nude mice bearing Bel-7402 tumor xenografts via a combination of LHPP-triggered nonferrous ferroptosis and GOA-induced chemotherapy. The biocompatibility of GOA/miR-363-5pi is strongly supported by their non-hematologic toxicity and insignificant organ damage. In addition, the tumor immunogenic activation potential of GOA/miR-363-5pi was finally explored. Overall, this study is the first work that elucidates the precise mechanism of LHPP for treating HCC via ferroptosis induction and achieves the transformation of chemotherapy and gene therapy into ferroptosis activation with tumor cell immunogenicity, which lays a new therapeutic foundation for the clinical treatment of HCC.Graphical

Retrospective analysis of survival and safety of bevacizumab biosimilar and original drug combination chemotherapy in non-small cell lung cancer.

The advent of bevacizumab has considerably transformed the therapeutic landscape for non-small cell lung cancer (NSCLC) patients devoid of specific genetic mutations. A pivotal milestone has been reached with the recent approval of a bevacizumab biosimilar, following rigorous phase III clinical investigations, poised to augment NSCLC therapeutic strategies. This retrospective analysis encompasses a large-scale study conducted between January 2021 and December 2023, involving 1058 NSCLC patients (metastatic or locally advanced stages). The research design entailed a comparative assessment of the safety and efficacy profiles of combined therapies using the original bevacizumab and its biosimilar, adhering to RECIST v1.1 criteria. Adverse event grading was standardized using the National Cancer Institute's CTCAE v5.0. Notably, the biosimilar demonstrated an objective response rate (ORR) of 29.79% in 606 patients, closely paralleling the 27.41% ORR observed in 452 patients receiving the original drug, with insignificant risk differences (-0.03) and a risk ratio of 0.987, affirming equivalence. Progression-free survival (PFS) was influenced by radiation status, treatment lines, and regimen combinations, while dosage intensity and genetic factors had negligible impacts. The incidence of treatment-emergent adverse events (TEAEs) was slightly higher in the biosimilar group (75.11%) versus the original drug group (72.78%), with grade 3 or more severe TEAEs occurring in 23.6% and 18.5% of patients, respectively (Detailed criteria for the definition and assessment of TEAEs have been added to the Methods section, including the use of the National Cancer Institute's CTCAE v5.0 for grading). The study affirms that bevacizumab biosimilars offer equivalent therapeutic efficacy and a similar safety profile to the originator product in the management of locally advanced or metastatic NSCLC. The tolerability of the toxicity profile, coupled with the absence of unforeseen adverse reactions, underscores the viability of biosimilar bevacizumab as a valuable addition to NSCLC treatment regimens. These findings also imply potential benefits for a broader patient population beyond clinical trial confines through the adoption of biosimilar beta-adrenergic blocking agents.

Risk score model for predicting mortality among patients with lung cancer.

To develop an accurate mortality risk predictive model among patients with lung cancer. The development cohort included 96,255 patients with lung cancer aged ≥19 years, who underwent a Korean National Health Insurance Service health check-up from 2005 to 2015. The validation cohort consisted of 18,432 patients (≥19 years) with lung cancer from another region. The outcome was all-cause mortality between January 1, 2005, and December 31, 2020. Approximately 60.5% of the development cohort died within a median follow-up period of 2.32 (0.72-5.00) years. Risk score was highest in participants aged ≥65 years, followed by those who underwent treatment, had a history of emergency room visits, and were current smokers. Participants treated by surgery had the lowest risk score, followed by combined surgery and chemotherapy, combined surgery and radiation therapy, women, and regular exercisers. The C statistic in the development and validation cohorts was 0.78 (95% confidence interval, 0.77-0.78) and 0.81 (95% confidence interval, 0.78-0.84), respectively. Advanced age, lung cancer stage, and treatment type were strong risk factors of mortality in lung cancer patients, while being a woman and exercise were preventive factors. These will aid in the prediction of mortality and management of lung cancer patients.

Pharmacodynamics of Rivaroxaban and Dabigatran in Adults with Diffuse Large B-Cell Lymphoma Receiving R-CHOP Immunochemotherapy.

Background/Objectives: Rivaroxaban and dabigatran are commonly used for thromboembolic disease management in active cancer patients. However, limited research explores the impact of concurrent chemotherapy on the pharmacodynamics of direct oral anticoagulants (DOAC). The aim of our study was to evaluate the impact of combined chemotherapy with rivaroxaban and dabigatran on the pharmacodynamics in patients with diffuse large B-cell lymphoma (DLBCL).; Methods: This was a prospective, pharmacodynamic study. Eligible subjects were ≥18 years old, diagnosed with DLBCL and initiating R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) immunochemotherapy. The enrolled adults received either rivaroxaban (10 mg once daily) or dabigatran etixalate (110 mg twice daily). Plasma anti-factor Xa (FXa) in participants on rivaroxaban and diluted thrombin time (dTT) in participants on dabigatran were assessed over the dosing interval before and after R-CHOP administration. Pharmacodynamic parameters of rivaroxaban and dabigatran were determined using a non-compartmental analysis.; Results: Twenty-six adults participated, with twelve in the rivaroxaban group and fourteen in the dabigatran group. The mean age was 59 ± 14.4 years. In the rivaroxaban group, the AUEC of FXa inhibition showed no significant change after R-CHOP (mean difference 3.8 ng·h/mL, 95% confidence interval (CI) -155.4 to 163.0, p = 0.96). Similarly, in the dabigatran group, the AUEC of dTT remained unchanged post R-CHOP (mean difference 54.41 ng·h/mL, 95% CI -99.09 to 207.9 ng/mL, p = 0.46). However, the median time-to-peak dTT was significantly faster with R-CHOP (3 h, [min-max, 1.5-8] compared to without it (4 h, [min-max, 3-8], p = 0.04); Conclusions: Concurrent R-CHOP chemotherapy did not significantly impact FXa inhibition by rivaroxaban or dTT by dabigatran. The time-to-peak dTT was faster when dabigatran was administered with R-CHOP.

Updated EANO guideline on rational molecular testing of gliomas, glioneuronal, and neuronal tumors in adults for targeted therapy selection - Update 1.

The standard of care for adult patients with gliomas, glioneuronal and neuronal tumors consists of combinations of surgery, radiotherapy, and chemotherapy. For many systemic cancers, targeted treatments are a major part of the standard treatment, however, the predictive significance of most of the targets for treatment in systemic cancer are less well established in central nervous system (CNS) tumors . In 2023 the EANO Guideline Committee presented evidence based recommendations for rational testing of molecular targets for targeted treatments. From all targets reviewed, only testing for BRAF V600E mutations was of proven clinical benefit; despite regulatory approvals for tumor agnostic treatment of NTRK gene fusions and high Tumor Mutational Burden (TMB) for patients with adult brain tumors, the evidence of clinical benefit for patients was still limited . This guideline has a modular structure, allowing regular updating of individual sections and adding new ones. The present version (Update 1) presents a review of the rationale of testing for PTEN, H3F3A, MTAP, RET and IDH, and presents an update of the text on TMB high and mismatch repair deficiency. It also presents an overview of therapeutic yield of routine next generation sequencing for mutations and fusion detection. The supplement accompanying this version contains the in depth review of all targets, whereas in the main manuscript the final recommendations of the revised and new targets are presented. Updates will be made on a regular basis.

Treatment of malignant primary cardiac tumors requires attention to cardiovascular complications: a single-center, retrospective study.

Malignant primary cardiac tumors require multimodal approaches including surgery, chemotherapy and radiotherapy, but these treatments can be associated with cardiovascular complications. However, few reports have described the cardiovascular complications related to primary cardiac tumor treatment because of their rarity. Clinical records of patients with primary cardiac tumors treated at Kyushu University Hospital from January 2010 to August 2021 were retrospectively examined. Of the 47 primary cardiac tumor patients, 13 (28%) were diagnosed with malignancy, including 5 angiosarcomas, 3 intimal sarcomas, 3 diffuse large B-cell lymphomas, 1 Ewing's sarcoma and 1 fibrosarcoma. Cardiovascular events were observed in 10 patients (77%), including cardiac dysfunction in 6 patients, arrhythmias in 5 patients, right heart failure in 2 patients, and excessively prolonged prothrombin time due to the combination of warfarin and chemotherapy in 1 patient. Two patients who showed notable cardiac complications are described. Case A involved a 69-year-old woman who underwent surgery for a left atrial intimal sarcoma, followed by postoperative chemotherapy with doxorubicin plus ifosfamide and radiotherapy. After three cycles of chemotherapy and sequential radiotherapy, her left ventricular ejection fraction decreased to 34%, and ongoing heart failure therapy was required. Case B involved a 66-year-old man who received chemotherapy for primary cardiac lymphoma, resulting in tumor shrinkage. However, due to tumor involvement of the intraventricular septum, atrioventricular block developed, requiring cardiac pacemaker implantation. High incidences of cardiac failure and arrhythmias were observed during multimodal treatments for malignant primary cardiac tumors. Proper management of complications may lead to a favorable prognosis in patients with malignant primary cardiac tumors.

Impact of upfront adjuvant chemoradiation on survival in patients with molecularly defined oligodendroglioma: the benefits of PCV over TMZ.

Oligodendroglioma is an adult-type diffuse glioma defined by 1p/19q codeletion and IDH1/2 mutation. Treatment includes surgery followed by observation alone in select low-grade tumors, or combination radiation and chemotherapy with procarbazine, lomustine, and vincristine (PCV) or temozolomide (TMZ). While prospective studies investigating treatments for molecularly defined oligodendrogliomas are ongoing, this retrospective study analyzes the relationship between adjuvant regimens and progression-free survival (PFS). Adults with IDH-mutant, 1p/19q codeleted oligodendroglioma (WHO grade 2 or 3) who underwent surgery between 2005 and 2021 were identified. Clinical data, disease characteristics, treatment, and outcomes were collected. A total of 207 patients with grade 2 and 70 with grade 3 oligodendrogliomas were identified. Median (IQR) follow-up was 57 (87) months. Patients with grade 3 tumors who received adjuvant radiation and PCV had longer median PFS (> 110 months) than patients who received radiation and TMZ (52 months, p = 0.008) or no adjuvant chemoradiation (83 months, p = 0.03), which was not seen in grade 2 tumors (p = 0.8). In multivariate analysis, patients who received PCV chemotherapy (Relative Risk [95% CI] = 0.24[0.05-1.08] and radiotherapy (0.46[0.21-1.02]) trended towards longer PFS, independently of grade. Adjuvant radiation and PCV are associated with improved PFS over radiation with TMZ in patients with grade 3 molecularly defined oligodendrogliomas, and all-grade patients treated with PCV trended towards decreased risk of recurrence and progression. These results highlight the importance of ongoing clinical trials investigating these treatments.

Aging affects regrowth of stealthperitoneal dissemination of advanced ovarian cancer: a multicenter retrospective cohort study

Ovarian cancer (OvCa) is one of the most lethal gynecological malignancies, and most patients are diagnosed at advanced stage with peritoneal dissemination. Although age at diagnosis is considered an independent prognostic factor, its impact on peritoneal recurrence after combined cytoreductive surgery and chemotherapy is not clear. The objective of this study was to investigate the impact of aging on peritoneal recurrence from stealth dissemination and gain insight of the pathophysiology of OvCa in elderly patients. A total of 243 patients with pT2b-pT3 epithelial ovarian who achieved complete surgery, no-residual tumor at first surgery, were selected to be analyzed the risk of peritoneal seeding and recurrence. We found that age over 65 years was independently associated with an increased risk of peritoneum-specific (PS) recurrence (. Furthermore, pT3 stages and positive ascites cytology also worsen the PS-relapse-free survival. Collectively, our findings suggest that age, especially over 65 years, predicts reduced peritoneum-specific tumor recurrence in patients with advanced ovarian cancer after complete cytoreduction surgery, particularly those with pT3 tumors and positive ascites cytology.

Expression Analysis of Caspase-3 (CASP3) Gene in Leukemia Patients Using Quantitative Polymerase Chain Reaction (qPCR) and Western Blot Techniques

CASP3 belongs to the caspases family and accounts for several critical activities, including apoptosis and other pathological and physiological processes. CASP3 also influences the multiple functions in cellular development such as homeostasis, hematopoietic growth and embryonic growth. It has significant involvement in the initiation and development of cancers including breast, colon and uterine cancers. However, molecular studies on the CASP3 gene in leukemia have not been widely conducted. The present study was designed to analyse the expression level of the CASP3 gene in leukemia patients. The results were further compared between different parameters such as types of leukemia, age, gender, occupation, WBC count and location-based. About 112 leukemia blood samples along adjacent controls were collected to analyse the CASP3 expression in this study cohort. The mRNA of each patient and control samples were isolated, quantified and converted to complementary DNA (cDNA). Relative expression of the CASP3 gene was measured using the quantitative PCR (qPCR) and Western blot analyses. Results showed that the relative expression of CASP3 was found to be significantly downregulated at both mRNA and protein levels in leukemia patients compared to normal controls. Further analysis showed that expression of CASP3 was downregulated in patients receiving the combination of chemotherapy as well as radiotherapy compared with patients receiving chemotherapy. These findings from our research showed the lower expression of CASP3 is associated with an increased risk of development and proliferation of leukemia. It can, therefore, be concluded that lower expression of the CASP3 gene may contribute to the initiation and development of leukemia.

Therapeutic advantage of combinatorial CAR T cell and chemo-therapies.

Chimeric antigen receptor (CAR) T cell therapies have transformed outcomes for many patients with hematological malignancies. However, some patients do not respond to CAR T cell treatment, and adapting CAR T cells for solid and brain tumors has been met with many challenges including a hostile tumor microenvironment and poor CAR T cell persistence. Thus, it is unlikely that CAR T cell therapy alone will be sufficient for consistent, complete tumor clearance across cancer patients. Combinatorial therapies of CAR T cells and chemotherapeutics are a promising approach for overcoming this as chemotherapeutics could augment CAR T cells for improved anti-tumor activity or work in tandem with CAR T cells to clear tumors. Herein, we review efforts towards achieving successful CAR T cell and chemical drug combination therapies. We focus on combination therapies with approved chemotherapeutics as these will be more easily translated to the clinic, but also review non-approved chemotherapeutics and drug screens designed to reveal promising new CAR T cell and chemical drug combinations. Together, this review highlights the promise of CAR T cell and chemotherapy combinations with specific focus on how combinatorial therapy overcomes challenges faced by either monotherapy and supports the potential of this therapeutic strategy to improve outcomes for cancer patients. Significance Statement Improving currently available CAR T cell products via combinatorial therapy with chemotherapeutics has the potential to drastically expand the types of cancers and number of patients that could benefit from these therapies when neither alone has been sufficient to achieve tumor clearance. Herein, we provide a thorough review of the current efforts towards studying CAR T and chemotherapy combinatorial therapies and provide perspectives on optimal ways to identify new and effective combinations moving forward.

Co-occurrence of rectal and lung cancers: A case report

Co-occurrence of two types of cancers, especially lung and colorectal cancers is rare. This study investigated patients at Bach Mai Hospital who were diagnosed with two or three cancers. Only a few patients concurrently had two cancers. Positron emission tomography (PET)/computed tomography (CT) was used for the staging of cancer, especially synchronous malignancies. In this report, we have presented the case of a patient diagnosed with rectal and lung cancer based on CT, magnetic resonance imaging, and PET/CT scans as well as immunohistochemistry. Managing terminal synchronous cancers is challenging. The efficacy of the preferred anticancer therapy must be considered to ensure patients’ quality of life. Although the combination of tyrosine kinase inhibitor-targeted therapy and chemotherapy is promising, its toxicity remains unknown. Our patient received two cycles of mFOLFOX6, afatinib, and bisphosphonate. However, the treatment was discontinued due to grade 3 stomatitis and grade 2 anemia. Despite recovery and partial response in terms of symptom and tumor marker reduction, the patient refused further treatment and chose palliative care.

6850 A Case of Anaplastic Thyroid Carcinoma With a Complete Metabolic Response to Pembrolizumab

Abstract Disclosure: E. Tirthani: None. J.T. Kung: None. Background: Anaplastic thyroid carcinoma (ATC) is an aggressive disease with limited therapeutic options and generally poor prognosis. Post-surgery, most patients are treated with a combination of chemotherapy, radiation, and tyrosine kinase inhibitors +/- immune checkpoint inhibitors. We describe a unique case of ATC with a complete metabolic response to pembrolizumab, a selective PD-1 inhibitor, as evidenced by imaging. Clinical Case: A 69-year-old female presented to the clinic for evaluation of a rapidly enlarging neck mass. The initial ultrasound showed a large mixed cystic-solid right thyroid nodule with irregular margins with micro- and macrocalcifications, which was biopsied. Cytology showed discohesive high-grade malignant tumor cells with enlarged nuclei, nuclear hyperchromasia in the background of necrosis, and dense neutrophilic infiltration concerning for ATC. A CT scan of the neck and chest showed a complex cystic thyroid mass with central necrosis and calcification with paratracheal, supraclavicular, and mediastinal lymphadenopathy. MRI of the brain was negative for metastatic disease. The patient underwent a total thyroidectomy with right and left level 6 and 7 neck dissection. Intra-operatively, gross extrathyroidal extension of the tumor was noted to the right carotid, larynx, right recurrent laryngeal nerve, and esophagus, with residual tumor left behind near the larynx. Pathology confirmed stage IVC ATC, positive for PIK3CA, NF1, p53 mutations, and BRAF negative. 90% of tumor cells showed PD-L1 expression on immunohistochemical staining. The post-surgical PET scan showed two discrete, well-defined foci of very intense FDG uptake, corresponding to the right lower cervical and para-esophageal lymph nodes with no evidence of distant metastasis. Systemic chemotherapy with carboplatin and paclitaxel (5 cycles) was initiated with concurrent intensity modulated radiation therapy (total 60 Gy/40 fractions to thyroid bed and bilateral neck). Repeat imaging showed minimal change in the size of the PET-positive lymph nodes. Immunotherapy was initiated and with just 2 cycles of 400 mg IV pembrolizumab, a repeat PET scan was obtained, which showed a complete metabolic response to therapy. Minimal residual FDG activity in the right supraclavicular region was thought to be secondary to posttreatment changes. The patient was able to resume her activities of daily living and had an improvement in appetite. The plan is to continue 400 mg IV pembrolizumab every 6 weeks while cautiously assessing for adverse effects from immunotherapy. Conclusion: It is rare to see a complete metabolic response to therapy with pembrolizumab without concurrent use of tyrosine kinase inhibitors in patients with ATC. A high tumoral PD-L1 expression may be the key to having this kind of dramatic response. Presentation: 6/3/2024

7888 Mitotane Induces Different Modes Of Cell Death In Treatment Resistant And Sensitive Models Of Adrenocortical Carcinoma

Abstract Disclosure: S. Feely: None. N. Mullen: None. C. Hong: None. C. Hantel: None. W.E. Rainey: None. M.C. Dennedy: None. Adrenocortical carcinoma (ACC) is a rare aggressive cancer with poor survival. Adjuvant mitotane is the only approved drug for treatment of ACC. It improves survival but its use is limited by poor tolerability and drug resistance. For metastatic ACC, combination chemotherapy, using mitotane and etoposide, doxorubicin, and cisplatin improves survival, but efficacy is limited. Better understating the cytotoxic mechanisms of mitotane offers potential to develop improved therapeutic options for ACC. To investigate the underlying mechanisms in vitro, human ACC cells (HAC15 and H295R), in monolayer cell culture were treated with increasing concentrations of mitotane. Cell death was evaluated at 6 and 24 hours using flow cytometry analysis of Annexin V and Sytox Blue. This was complemented by Incucyte ® Live-Cell Analysis System imaging of annexin V and Sytox Blue staining. Expression of the markers of apoptosis, cleaved caspase 3, and necroptosis, phosphorylated MLKL and RIPK1 was measured at 6 and 24 hours. Mitotane significantly reduced the viability of H295R cells at 6 and 24 hours at the therapeutic concentration of 50uM (p>0.0001), thereby demonstrating treatment-sensitivity. In HAC15 cells, a supratherapeutic dose of 200uM was needed to significantly reduce viability (p>0.05) at 24 hours, indicating resistance to mitotane treatment at therapeutic concentrations. There was increasing Annexin V fluorescence with increasing mitotane concentration in H295R and HAC15 cells ar 6 and 24 hours without higher coinciding staining with Sytox Blue. Video analysis demonstrated these findings. Cleaved caspase 3 expression was associated with mitotane-induced cell death in H295R cells at 6 and 24 hours, indicating apoptosis. HAC15 cells demonstrated cleaved caspase 3 expression only at the highest concentration of mitotane exposure (600uM) at 6 hours, without appreciable expression at 24 hours. Phosphorylated-MLKL and RIPK1 expression was seen in controls and all mitotane doses in both cell lines at both timepoints, indicating necroptosis. In this study, H295R cells, representing a treatment-sensitive model of Mitotane undergo both apoptotic and necroptotic cell death at 6 and 24 hours of mitotane exposure. In contrast, HAC15 cells, demonstrated relative treatment resistance to mitotane, and undergo necroptotic cell death only. These results highlight the importance of understanding and targeting non-apoptotic and necroptotic cell death pathways, particularly when evaluating mechanisms of treatment resistance in ACC. Given the difference in the mechanism of cell death in treatment-sensitive and treatment-resistant cells, further exploration of necroptosis is necessary to better understand how ACC cells may manifest treatment resistance. Presentation: 6/1/2024

7799 Nesidioblastosis Concurrent with Anatomically Confirmed Metastatic Gastric Cancer

Abstract Disclosure: Y. Cho: None. K. Jo: None. J. Han: None. S. Moon: None. E. Kim: None. Background: Nesidioblastosis is a rare condition that should be considered in cases of pancreatogenic hyperinsulinemic hypoglycemia without evidence of insulinoma on imaging. We present the first case of nesidioblastosis concomitant with anatomically confirmed metastatic gastric cancer of the pancreas. Case Report A 57-year-old male presented with recurrent episodes of loss of consciousness and hypoglycemia, with a glucose level of 26 mg/dl upon arrival at the emergency room. Despite a history of advanced gastric cancer and previous chemotherapy, the patient had not been diagnosed with diabetes and was not taking medications associated with hypoglycemia. Four months prior, he underwent total gastrectomy. The fasting plasma glucose levels was 38 mg/dl, accompanied by C-peptide levels of 6.10 ng/mL, insulin levels exceeding 1000 uIU/ml, and proinsulin levels at 8.8 pmol/L. The insulin antibody level was more than 100%, and the highest cortisol level reached 15.60 ug/dL during the rapid ACTH stimulation test. The patient's postprandial 2-hour glucose level reached 233 mg/dl during the 75g glucose tolerance test. Imaging studies, including whole-body PET CT and abdominal CT, showed no evidence of suspected metastatic lesions, and the pancreas appeared normal on MRI. Endoscopic ultrasound could not be performed due to anatomical changes following the surgery. A selective arterial calcium stimulation test demonstrated a substantial over twofold increase in insulin concentrations in the gastroduodenal artery, splenic artery, and superior mesenteric artery. The patient received methylprednisolone 125 mg once daily but insulin levels remained elevated, exceeding 1000 uIU/ml, requiring continuous dextrose infusion. Octreotide therapy was initiated, resulting in an improvement in insulin levels to 589 uIU/ml, although discontinuation of dextrose fluid remained unfeasible. After consultation with the surgeon, a open subtotal pancreatectomy was performed, allowing discontinuation of dextrose on the second post-surgery day, with improved glucose and insulin levels. Histological examination showed three clusters of atypical cells with perineural infiltration. Immunostaining indicated negative synaptophysin and positive CK20, suggesting possible gastric cancer metastasis, consistent with prior gastrectomy findings. Moreover, an increased number of variable-sized Langerhans islets exhibited positive insulin and glucagon immunostaining within the islets, indicative of nesidioblastosis. Conclusion: Nesidioblastosis should be considered in cases of unexplained post-surgery hypoglycemia following metastatic gastric cancer treatment. Furthermore, given the potential link with metastatic gastric cancer, which may elude detection via imaging alone, aggressive surgical intervention should be contemplated as a nesidioblastosis treatment strategy. Presentation: 6/3/2024

Clinical and pathological characteristics of gastric large cell neuroendocrine carcinoma: A report of 2 cases series and literature review.

Gastric large cell neuroendocrine carcinoma (LCNEC) is a rare, aggressive neuroendocrine carcinoma that arises from the stomach and with high malignancy. Patients with gastric LCNEC usually have a poor prognosis. The standard treatment plan has not been established and its curative effect is poor. The present study described 2 cases diagnosed with gastric LCNEC and reviewed in depth the literature to improve our understanding more about this uncommon tumor and further to provide more experience to diagnose and treat this disease. The present study reported 2 cases of gastric LCNEC in male patients aged 51 and 73 years old, respectively. Both patients had epigastric discomfort, pain, acid reflux and heartburn. The medical history was unremarkable. The ulcerative lesion located at gastric was examined in the 2 patients by taking the esophagogastroduodenoscopy (EGO), computed tomography (CT) and digital gastrointestinal radiography (GI), that both were suspected gastric malignancy. Endoscopic biopsies of the tumor led to the initial diagnosis of gastric cancer. Postoperative pathological and immunohistochemical examinations of the surgical specimens confirmed that 1 case had mixed adeno-neuroendocrine carcinoma (MANEC) and the other had LCNEC. Both patients underwent surgical resection and received etoposide-cisplatin combination chemotherapy following surgery. The operation was successful. Both patients had uneventful recoveries following surgery, and had been followed-up regularly. The general condition was satisfactory, and no tumor metastasis was observed at present.