Tumor Relapse Research Articles

Phenotypic switching mechanisms determine the structure of cell migration into extracellular matrix under the ‘go-or-grow’ hypothesis

A fundamental feature of collective cell migration is phenotypic heterogeneity which, for example, influences tumour progression and relapse. While current mathematical models often consider discrete phenotypic structuring of the cell population, in-line with the ‘go-or-grow’ hypothesis (Hatzikirou et al., 2012; Stepien et al., 2018), they regularly overlook the role that the environment may play in determining the cells’ phenotype during migration. Comparing a previously studied volume-filling model for a homogeneous population of generalist cells that can proliferate, move and degrade extracellular matrix (ECM) (Crossley et al., 2023) to a novel model for a heterogeneous population comprising two distinct sub-populations of specialist cells that can either move and degrade ECM or proliferate, this study explores how different hypothetical phenotypic switching mechanisms affect the speed and structure of the invading cell populations. Through a continuum model derived from its individual-based counterpart, insights into the influence of the ECM and the impact of phenotypic switching on migrating cell populations emerge. Notably, specialist cell populations that cannot switch phenotype show reduced invasiveness compared to generalist cell populations, while implementing different forms of switching significantly alters the structure of migrating cell fronts. This key result suggests that the structure of an invading cell population could be used to infer the underlying mechanisms governing phenotypic switching.

Automatic Detection of Post-Operative Clips in Mammography Using a U-Net Convolutional Neural Network.

After breast conserving surgery (BCS), surgical clips indicate the tumor bed and, thereby, the most probable area for tumor relapse. The aim of this study was to investigate whether a U-Net-based deep convolutional neural network (dCNN) may be used to detect surgical clips in follow-up mammograms after BCS. 884 mammograms and 517 tomosynthetic images depicting surgical clips and calcifications were manually segmented and classified. A U-Net-based segmentation network was trained with 922 images and validated with 394 images. An external test dataset consisting of 39 images was annotated by two radiologists with up to 7 years of experience in breast imaging. The network's performance was compared to that of human readers using accuracy and interrater agreement (Cohen's Kappa). The overall classification accuracy on the validation set after 45 epochs ranged between 88.2% and 92.6%, indicating that the model's performance is comparable to the decisions of a human reader. In 17.4% of cases, calcifications have been misclassified as post-operative clips. The interrater reliability of the model compared to the radiologists showed substantial agreement (κreader1 = 0.72, κreader2 = 0.78) while the readers compared to each other revealed a Cohen's Kappa of 0.84, thus showing near-perfect agreement. With this study, we show that surgery clips can adequately be identified by an AI technique. A potential application of the proposed technique is patient triage as well as the automatic exclusion of post-operative cases from PGMI (Perfect, Good, Moderate, Inadequate) evaluation, thus improving the quality management workflow.

The two-faced role of RNA methyltransferase METTL3 on cellular response to cisplatin in head and neck squamous cell carcinoma in vitro model.

RNA methyltransferase-like 3 (METTL3) is responsible for methyl group transfer in the progression of N 6-methyladenosine (m6A) modification. This epigenetic feature contributes to the structural and functional regulation of RNA and consequently may promote tumorigenesis, tumor progression, and cellular response to anticancer treatment (chemo-, radio-, and immunotherapy). In head and neck squamous cell carcinoma (HNSCC), the commonly used chemotherapy is cisplatin. Unfortunately, cisplatin resistance is still a major cause of tumor relapse and patients' death. Thus, this study aimed to investigate the role of METTL3 on cellular response to cisplatin in HNSCC in vitro models. HNSCC cell lines (H103, FaDu, and Detroit-562) with stable METTL3 knockdown (sgMETTL3) established with CRISPR-Cas9 system were treated with 0.5 tolerable plasma level (TPL) and 1 TPL of cisplatin. Further, cell cycle distribution, apoptosis, CD44/CD133 surface marker expression, and cell's ability to colony formation were analyzed in comparison to controls (cells transduced with control sgRNA). The analyses of cell cycle distribution and apoptosis indicated a significantly higher percentage of cells with METTL3 knockdown 1) arrested in the G2/S phase and 2) characterized as a late apoptotic or death in comparison to control. The colony formation assay showed intensified inhibition of a single cell's ability to grow into a colony in FaDu and Detroit-562 METTL3-deficient cells, while a higher colony number was observed in H103 METTL3 knockdown cells after cisplatin treatment. Also, METTL3 deficiency significantly increased cancer stem cell markers' surface expression in all studied cell lines. Our findings highlight the significant influence of METTL3 on the cellular response to cisplatin, suggesting its potential as a promising therapeutic target for addressing cisplatin resistance in certain cases of HNSCC.

EPID-06. PEDIATRIC BRAIN TUMOUR DIAGNOSTIC DELAY DURING COVID-19 PANDEMIC IN A REGIONAL NEURONCOLOGY CENTRE

Abstract BACKGROUND The Pediatric Central Nervous System (CNS) tumors incidence has increased in the last decades. A diagnostic delay could be related to adverse effects involving neurosurgical approach. Moreover, many studies report that Coronavirus-19 pandemic has even increased the diagnostic delay of solid tumors, in particular CNS types. METHODS We conducted a retrospective study including all pediatric patients who received a diagnosis of CNS tumor at Udine Hospital between January 2020 and December 2021. Our first aim was to assess if there has been a variation in the incidence rate and a possible diagnostic delay of CNS pediatric tumors during 2020-2021. As a secondary objective we evaluated if the Coronavirus-19 pandemic has affected our ability to identify tumor relapses caused by delays in planning follow-up exams and imaging. Data of every patient were recorded and compared with data from a historical cohort recruited between 2000 and 2011. RESULTS 25 patients were enrolled in the study: 19 (11 males) were diagnosed with a primitive CNS tumor, 7 (3 males) with a secondary lesion. Incidence rate during 2020-2021 was 5.17 per 100.000 inhabitants (age 0-18 years) and median diagnostic interval was 6.7 weeks, both higher than in the historical cohort (but not statistically significant). Median age was 10 +/- 4,7 age (IQR 25°-75°5,9-13,7). No substantial variation of clinical presentation was detected, although some symptoms were found to be more frequent than in the past. A significant rise in the number of high histological grade tumors was recorded (63% vs 12%, p value < 0.001), but there was no difference in tumor relapses diagnostic delay (median 6,7 weeks compared with 5 weeks in historical cohort). CONCLUSIONS Coronavirus-19 pandemic had no impact in diagnostic delay, planning and execution of follow-up exams in children with CNS tumors.

Exploring the Potential of Natural Killer Cell-Based Immunotherapy in Targeting High-Grade Serous Ovarian Carcinomas.

High-grade serous ovarian cancers (HGSOCs) likely consist of poorly differentiated stem-like cells (PDSLCs) and differentiated tumor cells. Conventional therapeutics are incapable of completely eradicating PDSLCs, contributing to disease progression and tumor relapse. Primary NK cells are known to effectively lyse PDSLCs, but they exhibit low or minimal cytotoxic potential against well-differentiated tumors. We have introduced and discussed the characteristics of super-charged NK (sNK) cells in this review. sNK cells, in comparison to primary NK cells, exhibit a significantly higher capability for the direct killing of both PDSLCs and well-differentiated tumors. In addition, sNK cells secrete significantly higher levels of cytokines, especially those known to induce the differentiation of tumors. In addition, we propose that a combination of sNK and chemotherapy could be one of the most effective strategies to eliminate the heterogeneous population of ovarian tumors; sNK cells can lyse both PDSLCs and well-differentiated tumors, induce the differentiation of PDSLCs, and could be used in combination with chemotherapy to target both well-differentiated and NK-induced differentiated tumors.

LMIC-25. EXPANDING THE PEDIATRIC NEURO-ONCOLOGY TELECONFERENCE EXPERIENCES, A LUXURY, OR A NECESSITY?

Abstract INTRODUCTION Videoteleconference in neurooncology is feasible and sustainable. The well-established 20 years’ Sickkids/KHCC teleconferencing is an example. Since 2018, several regional centers joined these meetings to discuss their patients’ management plans. We aimed to evaluate the impact of this experience. METHODS We retrospectively reviewed the 56 meetings’ minutes (9/2018-12/2023) and compared the pre-conference suggested plans with the post-conference recommendations. We recorded if the recommendations were implemented and the impact perceived. RESULTS In total, 251 patients were discussed: KHCC (137) and non-KHCC (114). Four of the regional participating oncologists had dedicated pediatric neuro-oncology training. Patients were selected for discussion due to challenges in their management (i.e. with relapsed tumors, rare diagnoses, unexpected tumor behavior). Main diagnoses were: Low-grade-glioma (28%), High-grade-glioma (21%), and Medulloblastoma (17%). Of the 227 patients where the local team suggested a care plan, the teleconference recommendations concurred with the proposed plan in 50% of the cases, agreed on but provided an alternative plan option in 18% and disagreed on in 32% of the cases. The difference in recommendations mostly affected the proposed treatment modality (15%). In 64% of the discordant plans and 50% of the alternative plans, the treating team applied the recommendations. Challenges to apply the recommendations were mainly linked to patients’ factors (53%, plan refusal, traveling abroad, clinical deterioration), local multidisciplinary team consensus on a different plan (29%) or logistic difficulties (18%, e.g. drug access). CONCLUSIONS Improvement in patients’ care was likely achieved with the continuous effort of the local teams to implement the recommendations. Participating oncologists valued the shared educational experience learned from each other’s case discussions, especially those related to molecular-testing and implications on treatment. Joining such regional teleconferences is of particular importance to small-volume centers or those lacking a pediatric neurooncologist. Regional and international collaborations are a necessity when it comes to improving the care of children with CNS tumors.

DIPG-40. LONG TERM SURVIVAL OF A 14 YEAR OLD GIRL WITH H3K27M MUTATED DIFFUSE MIDLINE GLIOMA FOLLOWING RADIOTHERAPY AND PROLONGED TUMOR TREATING FIELDS (TTFIELDS) -CASE REPORT

Abstract INTRODUCTION Pediatric diffuse midline H3K27M mutated glioma has a dismal prognosis. Most cases are treated by radiotherapy and oral chemotherapy, with surgical resection having a debatable role in some. Tumor-treating fields (TTFields) is a noninvasive modality in which alternating electrical fields exert biophysical force on charged and polarizable molecules known as dipoles. TTFields has been shown to extend survival for adult patients with newly diagnosed and recurrent GBM, and is FDA approved for these indications. There is sparse data about pediatric patients. CASE REPORT A 14-year-old girl presented with headache and vomiting. A large left thalamic tumor was diagnosed and underwent subtotal resection. Diagnosis was diffuse midline glioma, H3K27M positive, IDH negative. Molecular Panel: Tumor mutation burden low, microsatellite stable. Genomic findings: FGFR1, NF1, H3F3A -K28M, ATRX R666, MAP3K1 She was re-operated due to a fast tumor relapse within a few weeks, prior to radiotherapy, followed with radiotherapy with local field 59Gy. She then received temozolamide (12 months) concomitant with TTfields (Optune, Novocure). TTfields therapy was administered for 5 years without adverse effects and excellent compliance (above 85%). After 5 years, therapy was withheld, and she is now off therapy NED for another 15 months. DISCUSSION Diffuse midline H3K27M glioma harbors a poor prognosis in children. Children refrain from this treatment both for lack of evidence and because of the difficulty in adhering to a regimen that demands carrying a battery of 1.5-2kg all day and shaving all hair every 3 days. Our patient had a high compliance and as she wore a head scarf for religious customs, the device was not visible. To our knowledge this is the first pediatric reported case of long-term survival of H3K27mutatted midline glioma using TTFields. Further pediatric studies are warranted.

DIPG-27. MATCHED PRIMARY-RELAPSE PEDHGG PATIENT-DERIVED XENOGRAFT MODELS TO IDENTIFY THERAPY RESISTANCE PROFILES

Abstract BACKGROUND We established patient-derived xenografts (PDXs) from matched primary-relapse pairs of pediatric high-grade gliomas (pedHGGs) in collaboration with the Swedish Childhood Tumor Biobank. Further, we used human iPSC derived cortical organoids to evaluate interactions between glial and tumor cells under treatment pressure potentially lost in xenograft models. Using this setup, we hope to follow tumor relapse evolution and to identify novel mechanisms behind treatment evasion and relapse formation. METHODS Tumoral singel cell suspensions from matched primary-relapse pairs are injected orthotopically in immunodeficient NOG mice. We establish in vitro 2D models in stem cell conditions from the first generation of animals transplanted. Lentivirus-based labelling with GFP/Luciferase was done on PDX-derived cell lines to allow cell tracking and to quantify efficacy of drug screening efforts. Co-culture of these cells with normal cells in 3D assembloids were performed using 150-250 days old cortical organoids. Single-cell RNA sequencing and bulk RNA sequencing (RNA-seq) on patient biopsies, their corresponding PDXs from first generation of mice, and PDX-derived cell lines, was performed to track potential changes in vivo and in vitro and to further validate primary-relapse specific evolution. RESULTS 2D and 3D cell cultures offered efficient labeling and we quantified differences in sensitivity to standard therapy between primary and relapse samples. PDX models and assembloids highlighted pedHGG growth patterns, modes of invasion and cell interactions, especially astrocyte-tumor cell interactions. These 3D models also allow for further validation of targeted drug testing based on multiomics data (WGS, methylation and RNA-seq) from the patient biopsies. CONCLUSION PedHGG primary-relapse in vitro 2D cell line/ in vivo 3D assembloid models together with PDXs is a robust approach to study different aspects of relapse-specific tumor biology. Our results offer insights aiding the development of novel therapeutics inhibiting relapse mechanisms already in the first line of treatment.

ATRT-03. PRIMARY DIFFUSE LEPTOMENINGEAL ATYPICAL TERATOID/RHABDOID TUMOR (ATRT) OF CHILDHOOD DEMONSTRATING UNEXPECTED IMPROVEMENT UPON CESSATION OF CONVENTIONAL THERAPY FOR PRESUMED PROGRESSION; A MOLECULARLY CHARACTERIZED CASE REPORT

Abstract BACKGROUND Atypical teratoid/rhabdoid tumors (ATRTs) are malignant tumors of the central nervous system, typically presenting in the posterior fossa of very young children. Prognosis remains poor despite current therapy, while tumorigenesis implicates both genomic and epigenetic dysregulation. Primary diffuse leptomeningeal disease (PDL ATRT), without a defined intraparenchymal lesion, is an extremely rare ATRT variant with only seven cases reported. None of these preceding cases had undergone molecular characterization. We compared our case, who demonstrated an atypical clinical and radiological trajectory, against these seven cases. CASE PRESENTATION We describe a PDL ATRT, with hitherto novel molecular and imaging characteristics, in a pediatric patient who subsequently demonstrated radiological and clinical recovery from radiologically diagnosed metastatic relapse in the absence of conventional ATRT salvage treatment. Our case is the first to utilize Magnetic Resonance Imaging Arterial Spin Labelling perfusion imaging to suggest an underlying malignancy as the responsible etiology for this patient’s complex presentation, and the first to use methylation profiling to establish a tumor molecular subgroup for a PDL ATRT patient (identifying a MYC-subgroup in this case). CONCLUSIONS For this reported case of pediatric MYC-subgroup PDL ATRT, MR perfusional imaging aided in establishing the diagnosis and predicting potential relapse as part of a multi-parametric imaging assessment. We administered upfront intensive multimodal therapy, including high-dose CSRT to the patient, resulting in the longest overall survival for any patient reported with this extremely challenging ATRT variant. His unanticipated clinical and radiological improvement following a subsequent radiological diagnosis of tumor relapse highlights the importance of confirming recurrence by tissue extraction where feasible, but suggests that further evaluation of histone deacetylase inhibition as a potential future therapy in ATRT is warranted.

Thoracoscopic salvage esophagectomy with prophylactic mediastinal lymph node dissection after definitive chemoradiotherapy for patients with esophageal cancer.

Salvage esophagectomy for residual tumor and localized relapses after definitive chemoradiotherapy (dCRT) for patients with esophageal cancer is associated with a high rate of postoperative complications and in-hospital mortality. In addition, there are many controversial issues associated with salvage esophagectomy, such as the acceptability of minimally invasive surgery and the need for prophylactic dissection of mediastinal lymph nodes. The aim of this study was to evaluate the safety and usefulness of thoracoscopic salvage esophagectomy with prophylactic mediastinal lymph node dissection. The study included 31 patients who underwent thoracoscopic salvage esophagectomy with prophylactic mediastinal lymph node dissection after dCRT between 2013 and 2022 (salvage patients) and 610 nonsalvage patients who underwent conventional thoracoscopic esophagectomy during the same time period. Differences between the median ages and sexes of the 2 patient groups were not significant. The dominant location of tumors in the salvage patients was the upper thoracic esophagus. More salvage patients had clinical T4 disease. The salvage patients had a lower median number of retrieved mediastinal lymph nodes than the nonsalvage patients. The differences between the rates of R0, postoperative complications, and in-hospital deaths in the 2 patient groups were not significant. The 3-year overall survival (OS) rates for the salvage patients were 73%, with 3-year OS rates for R0 vs non-R0 of 81% vs 0%, p < 0.01 and pN0 vs pN1-3 of 89% vs 49%, p < 0.01. Regarding short-term outcomes, prophylactic mediastinal lymph node dissection for patients undergoing thoracoscopic salvage esophagectomy was as safe as prophylactic dissection for patients undergoing conventional thoracoscopic esophagectomy. R0 surgery and pN0 are important factors for long-term survival in patients undergoing thoracoscopic salvage esophagectomy.

Biomimetic Hydrogel-Mediated Mechano-Immunometabolic Therapy for Inhibition of ccRCC Recurrence After Surgery.

The unique physical tumor microenvironment (TME) and aberrant immune metabolic status are two obstacles that must be overcome in cancer immunotherapy to improve clinical outcomes. Here, an in situ mechano-immunometabolic therapy involving the injection of a biomimetic hydrogel is presented with sequential release of the anti-fibrotic agent pirfenidone, which softens the stiff extracellular matrix, and small interfering RNA IDO1, which disrupts kynurenine-mediated immunosuppressive metabolic pathways, together with the multi-kinase inhibitor sorafenib, which induces immunogenic cell death. This combination synergistically augmented tumor immunogenicity and induced anti-tumor immunity. In mouse models of clear cell renal cell carcinoma, a single-dose peritumoral injection of a biomimetic hydrogel facilitated the perioperative TME toward a more immunostimulatory landscape, which prevented tumor relapse post-surgery and prolonged mouse survival. Additionally, the systemic anti-tumor surveillance effect induced by local treatment decreased lung metastasis by inhibiting epithelial-mesenchymal transition conversion. The versatile localized mechano-immunometabolic therapy can serve as a universal strategy for conferring efficient tumoricidal immunity in "cold" tumor postoperative interventions.

Aqueous VEGF-A Levels as a Liquid Biopsy Biomarker of Retinoblastoma Vitreous Seed Response to Therapy.

Regression of retinoblastoma vitreous seeds (VS) during intravitreal chemotherapy can be delayed, resulting in supernumerary injections. Similarly, VS relapse may not be clinically evident at first. A predictive biomarker of tumor regression and relapse could help guide real-time clinical decision making. Retinoblastoma is an oxygen-sensitive tumor; paradoxically, VS survive in the hypoxic vitreous. We hypothesized that VS elaborate pro-angiogenic cytokines. The purpose was to determine if pro-angiogenic cytokine signatures from aqueous humor could serve as a biomarker of VS response to treatment. Multiplex ELISA was performed on aqueous from rabbit eyes with human retinoblastoma VS xenografts to identify expressed proangiogenic cytokines and changes in aqueous cytokine levels during intravitreal treatment were determined. Confirmatory RNAscope in situ hybridization for VEGF-A was performed on human retinoblastoma tumor sections and VS xenografts from rabbits. For human eyes undergoing intravitreal chemotherapy, serial aqueous VEGF-A levels measured via VEGF-A-specific ELISA were compared to clinical response. VEGF-A was highly expressed in human retinoblastoma VS in the xenograft model, and was the only proangiogenic cytokine that correlated with VS disease burden. In rabbits, aqueous VEGF-A levels decreased in response to therapy, consistent with quantitative VS reduction. In patients, aqueous VEGF-A levels associated with clinical changes in disease burden (regression, stability, or relapse), with changes in VEGF-A levels correlating with clinical response. Aqueous VEGF-A levels correlate with extent of retinoblastoma VS, suggesting that aqueous VEGF-A may serve as a predictive molecular biomarker of treatment response.

Sequential light irradiation-controlled cancer stemness inhibition for sensitized photothermal therapy

Cancer stem-like cells (CSCs) have a well-established role in mediating tumor relapse and resistance towards chemotherapy and radiation therapy. Photothermal therapy (PTT) is an efficient therapeutic strategy that uses light and photothermal agents to generate hyperthermia in tumors and kill cancer cells. However, due to the heterogeneity and drug resistance of CSCs, some of them may survive from PTT and cause recurrence and metastasis of tumors. In the study, we present a sequential dual-wavelength light-controlled drug delivery strategy, which combines 656 nm light-triggered drug release to inhibit cancer stemness, followed by 808 nm light-activated PTT to eradicate bulk tumors. The first light irradiation induces the release of γ-secretase inhibitor MK-0752 to deactivate Notch pathway, which is a key regulator of CSCs. Subsequently, the second light irradiation triggers hyperthermia to effectively kill tumor cells. Our findings demonstrate that inhibiting cancer stemness increases tumor sensitivity to PTT, resulting in effective growth inhibition of primary tumors with repressed tumorgenicity. This innovative dual-wavelength strategy holds promise for enhancing the efficacy of PTT in addressing the challenges posed by CSCs-rooted heterogeneity and drug resistance.

Abstract B010: Drug tolerant persister cancer cells escape therapy-induced senescence

Abstract Triple-negative breast cancer (TNBC) accounts for 15% of breast cancers and is the most aggressive subtype lacking precision oncology therapeutic strategies. Standard-of-care is predominantly chemotherapy in the neoadjuvant setting (NACT). Despite good responses, ∼40% of TNBC patients develop resistance and present residual disease at surgery. Overcoming resistance and implementing better therapeutic options is critical. Our objectives are to develop targeting opportunities for drug tolerant persister (DTP) cells which underlie residual disease. Using our unique biobank of patient derived xenografts from treatment naive as well as NACT resistant TNBC, we developed longitudinal in vivo models of residual and relapse tumors to standard-of-care therapy. Transcriptomic analysis revealed transient metabolic changes such as oxidative phosphorylation, starvation and autophagy, associated with hallmarks of senescence at residual disease. We demonstrated that therapy-induced senescent cells in vitro can escape cell cycle arrest and resume proliferation through autophagy. Interfering with autophagy impairs redox balance, promotes ferroptosis and delays tumor relapse. These results support that autophagy is a promising targetable vulnerability in TNBC residual disease. Citation Format: Anne-Marie Fortier, Jason Topolski, Gabriel Alzial, Anie Monast, Hellen Kuasne, Dongmei Zuo, Alain Pacis, Genevieve Deblois, Morag Park. Drug tolerant persister cancer cells escape therapy-induced senescence [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Expanding and Translating Cancer Synthetic Vulnerabilities; 2024 Jun 10-13; Montreal, Quebec, Canada. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(6 Suppl):Abstract nr B010.

The Expression of Forkhead Box P3 T Regulatory Lymphocytes as a Prognostic Factor in Malignant Melanomas.

Since transcription factor Forkhead Box P3 (FoxP3) was identified as a specific regulatory T cell (Treg) marker, researchers have scrutinized its value as a potential novel therapeutic target or a prognostic factor in various types of cancer with inconsistent results. The present analysis was performed to assess the influence of Treg FoxP3 expression on the prognosis of primary melanoma and to evaluate the correlations with various clinicopathological prognostic factors. We analyzed all eligible patients with stage pT3 primary malignant melanomas treated in a tertiary cancer center. Immunohistochemical staining for Treg FoxP3 expression was performed on retrospectively identified paraffin blocks and subsequently correlated with the outcomes of the patients. A total of 81% of the patients presented a positive Treg FoxP3 expression, being correlated with a higher risk of lymph node metastasis, tumor relapse, and death. Moreover, positive expression was statistically associated with a shorter OS. The tumor relapse rate was estimated at 36.7%. A positive expression of Treg FoxP3 and lymph node metastasis were associated with a higher risk of death based on multivariate analysis. Treg FoxP3 expression may be used as an independent prognostic factor in patients with malignant melanoma to evaluate tumor progression and survival.

Complement or Insult: the emerging link between complement cascade deficiencies and pathology of myeloid malignancies.

The complement cascade is an ancient and highly conserved arm of the immune system. The accumulating evidence highlights elevated activity of the complement cascade in cancer microenvironment and emphasizes its effects on the immune, cancer and cancer stroma cells, pointing to a role in inflammation-mediated etiology of neoplasms. The role the cascade plays in development, progression and relapse of solid tumors is increasingly recognized, however its role in hematological malignancies, especially those of myeloid origin, has not been thoroughly assessed and remains obscure. As the role of inflammation and autoimmunity in development of myeloid malignancies is becoming recognized, in this review we focus on summarizing the links that have been identified so far for complement cascade involvement in the pathobiology of myeloid malignancies. Complement deficiencies are primary immunodeficiencies that cause an array of clinical outcomes including an increased risk of a range of infectious as well as local or systemic inflammatory and thrombotic conditions. Here, we discuss the impact that deficiencies in complement cascade initiators, mid- and terminal- components and inhibitors have on the biology of myeloid neoplasms. The emergent conclusions indicate that the links between complement cascade, inflammatory signaling and the homeostasis of hematopoietic system exist, and efforts should continue to detail the mechanistic involvement of complement cascade in the development and progression of myeloid cancers.

The transcriptional landscape of cancer stem-like cell functionality in breast cancer

BackgroundCancer stem-like cells (CSCs) have been extensively researched as the primary drivers of therapy resistance and tumor relapse in patients with breast cancer. However, due to lack of specific molecular markers, increased phenotypic plasticity and no clear clinicopathological features, the assessment of CSCs presence and functionality in solid tumors is challenging. While several potential markers, such as CD24/CD44, have been proposed, the extent to which they truly represent the stem cell potential of tumors or merely provide static snapshots is still a subject of controversy. Recent studies have highlighted the crucial role of the tumor microenvironment (TME) in influencing the CSC phenotype in breast cancer. The interplay between the tumor and TME induces significant changes in the cancer cell phenotype, leading to the acquisition of CSC characteristics, therapeutic resistance, and metastatic spread. Simultaneously, CSCs actively shape their microenvironment by evading immune surveillance and attracting stromal cells that support tumor progression.MethodsIn this study, we associated in vitro mammosphere formation assays with bulk tumor microarray profiling and deconvolution algorithms to map CSC functionality and the microenvironmental landscape in a large cohort of 125 breast tumors.ResultsWe found that the TME score was a significant factor associated with CSC functionality. CSC-rich tumors were characterized by an immune-suppressed TME, while tumors devoid of CSC potential exhibited high immune infiltration and activation of pathways involved in the immune response. Gene expression analysis revealed IFNG, CXCR5, CD40LG, TBX21 and IL2RG to be associated with the CSC phenotype and also displayed prognostic value for patients with breast cancer.ConclusionThese results suggest that the characterization of CSCs content and functionality in tumors can be used as an attractive strategy to fine-tune treatments and guide clinical decisions to improve patients therapy response.

Tumor Budding as a Prognostic Marker in Primary Colon Cancer - A Single Center Experience.

Introduction: Tumor budding (TB) is considered to be a morphological and prognostic factor relevant to colon cancer (CC). The aim of our study is to assess the TB and to evaluate its relationship to clinicopathological findings within stage II and III CC patients as a single center experience. Materials and methods: A total of 120 CC patients operated between 2018 and 2021 at the University Clinic of Digestive Surgery in Skopje, the Republic of North Macedonia were included in this retrospective, single center study. TB was evaluated by the magnification of 200x along the invasive front of the primary tumor on H&E and CKAE1/AE3 immunohistochemically stained sections. Two grades were used: low grade (TB1, 0-4 TBs) and high-grade, which includes intermediate (TB2, 5-9 TBs) and high grade (TB3 ≥10TBs) of TBs. Results: A statistically significant correlation has been identified between high-grade TB and age (p=0.05) of the patients. There was also a significantly higher occurrence of high-grade TB in patients within stage III CC. Statistically significant correlations were also found in lymph node status (p<0.01), vascular invasion (p<0.05), lymphatic invasion (p<0.01), postoperative relapse (p<0.01), and death (p<0.01). Tumor relapse and death were significantly more frequent in patients with high-grade TB than those with low-grade TB. Patients with registered high-grade TB demonstrated significantly lower relapse-free survival (RFS) and overall survival (OS) rates than patients with low-grade TB over the observation period (RFS: 53.8% vs. 98.5%, p<0.001; OS: 65.4% vs. 97.1%, p<0.001, respectively). Patients with lung and liver postoperative relapses had higher percentage of cases with high-grade TB (94.1%). Conclusion: Our results are highly suggestive that TB should be included as a histological biomarker in the pathology report of patients with stage II and stage III CC, because of its prognostic value.

HER2 expression-independent antitumor effect of trastuzumab deruxtecan (T-DXd) on pediatric solid tumors.

e15016 Background: Treatment of pediatric solid tumors shows limited improvement even with intensification of conventional chemotherapy, suggesting novel approaches such as targeted therapies are needed. Trastuzumab Deruxtecan (T-DXd), a HER2-targeting antibody–drug conjugate, exhibits significant anti-cancer activity in breast cancers with a broad range of HER2 expression. T-DXd might be a promising agent for refractory or relapsed pediatric solid tumors, but its efficacy in pediatric tumors needs to be studied. Methods: Anti-cancer efficacy of T-DXd and its payload DXd were assessed in vitro by utilizing our in-house cancer cell line models. Cytotoxicity assays were performed for 60 pediatric cancer cell lines, including Neuroblastoma (NB) = 25, Ewing sarcoma / Ewing sarcoma family of tumors (EWS / EWSFT) = 17, Rhabdomyosarcoma (RMS) = 10, Others (Osteosarcoma, Brain tumor, Wilms tumor, Hepatoblastoma, and Malignant rhabdoid tumor (MRT) = 8, and 2 breast cancer cell lines expressing HER2 high or low (IHC score 2+ or 0) as positive or low control, respectively. We analyzed HER2 expression on the cell surface by flow cytometry and evaluated relative mean fluorescence intensity (MFI) values. Results: In the flow cytometric assessment, pediatric cancer cell lines showed smaller median MFI of 1.40 (0.67 - 2.71) compared with breast cancer control with HER2 high expression (33.77). The median MFI of each cell lines were 0.94 in NB, 1.76 in EWS / EWSFT, 1.42 in RMS, 1.52 in other pediatric cancers. Although low or no expression of HER2, certain inhibitory activities to the cell growth were observed for T-DXd against a part of NB, EWS, RMS and MRT cell lines, with the minimum IC50 values of 14.5 nM, 6.5 nM, 10.2 nM, 8.1 nM, respectively. In NB, EWS and RMS, a wide range of sensitivity to T-DXd were seen among different cell lines in the same disease. Most of cell lines showed high sensitivity to DXd (Median IC50 value: 0.90 nM [0.08 - 6.46 nM]), but, among them, cell lines with lower sensitivity to DXd tend to show less sensitivity to T-DXd. There was no clear correlation between sensitivity to T-DXd and HER2 expression among pediatric cancer cell lines, indicating that other mechanism such as intrinsic sensitivity to payload might affect antitumor activity of T-DXd. Conclusions: T-DXd exhibited antitumor efficacy against pediatric solid tumors in vitro irrespective of HER2 expression. Our results suggest that T-DXd might be an alternative therapy for pediatric solid tumor cases for whom conventional chemotherapies and other targeting therapies are ineffective. This study supports further investigation for T-DXd in this population.

A phase I/II study of C019199 in combination with sintilimab in advanced malignancy.

e15110 Background: C019199 is an oral CSF-1R/DDRs/VEGFR2 multiple kinase inhibitor and modulates the immune micro-environment of tumor cells. Previous phase I study of C019199 as a mono-therapy for advanced solid tumors has shown promising safety and anti-tumor activity. This phase I/II study is to evaluate the safety and efficacy of the combination of C019199 and Sintilimab in solid tumors. Methods: An open label, multicenter phase I/II study of C019199 combined with Sintilimab is currently enrolling (NCT06220318). Eligible subjects (age of ≥18 years and &lt;76 years) with histologically or cytologically confirmed relapsed, refractory, or progressive metastatic solid tumors will be enrolled in. This trial consists of 2 parts: a phase I dose escalation study using a standard 3+3 design with 3 doses of C019199 (100 mg/qd, 200 mg/qd, 300 mg/qd) combined with a fixed dose of Sintilimab (200 mg, iv, q3w) to determine the maximum tolerated dose (MTD) and recommended phase Ⅱ dose (PR2D); A phase II study is planned to enroll about 20 patients in each tumor type, including but not limited to the following: colorectal cancer, gastric cancer, esophageal squamous cell carcinoma, pancreatic cancer, triple negative breast cancer, head and neck squamous cell carcinoma. Results: A total of 10 patients with advanced solid tumors were enrolled in the phase I study from Jul 20, 2023 to Nov 14, 2023. Median age was 54 (range, 37-71), with 6 males and 4 females. Tumor types were colorectal cancer (7 pts), non-small cell lung cancer (2 pts) and cervical cancer (1 pts), with a median 3 prior systemic therapies (range, 1-7). As of Jan 15, 2024, we have assessed safety in all pts and efficacy in pts with at least one tumor assessment result. No dose-limiting toxicities (DLT) observed in the dose range of 100 mg/qd~300 mg/qd and the MTD has not been reached. The most frequently reported TRAEs were aspartate aminotransferase increased (80%), γ-glutamyltransferase increased (70%), proteinuria (70%), creatine kinase-MB increased (70%), alkaline phosphatase increased (60%). Grade ≥3 TRAEs were hypertension (30%), proteinuria (10%), immune hepatitis (10%), diarrhea (10%). Among 7 colorectal cancer patients, 1 subject had partial responds (PR) and 6 had stable disease (SD) as the best responds with ORR of 14.3%, DCR of 100%. Four subjects were still on treatment. Median PFS was not reached (&gt;3month). Two patients with non-small cell lung cancer and 1 patient with cervical cancer achieved the best response of SD, with a DCR of 100%. Phase II study is ongoing. Recommended dose is 200 mg/qd as the RP2D in selected solid tumors. Conclusions: The combination of C019199 and Sintilimab has shown good overall safety and tolerability. No DLT was observed in the dose range of 100 mg/qd ~ 300 mg/qd. Preliminary anti-tumor activity was observed in patients with advanced solid tumors. Phase II study is ongoing to accumulate more clinical data. Clinical trial information: NCT06220318 .