Intratumoral Lymphocytes Research Articles

Machine Vision-Detected Peritumoral Lymphocytic Aggregates are Associated with Disease-Free Survival in Papillary Thyroid Carcinoma Patients

Papillary thyroid carcinoma (PTC) is the most prevalent form of thyroid cancer, with a disease recurrence rate of around 20%. Lymphoid formations which occur in non-lymphoid tissues during chronic inflammatory, infectious, immune responses have been linked with tumor suppression. Lymphoid aggregates potentially enhance the body's anti-tumor response, offering an avenue for attracting tumor-infiltrating lymphocytes (TILs) and fostering their coordination. Increasing evidence highlights the role of lymphoid aggregate density in managing tumor invasion and metastasis, with a favorable impact noted on overall and disease-free survival (DFS) across various cancer types. In this work we present a machine vision model to predict recurrence in different histologic subtypes of PTC using measurements related to peritumoral lymphoid aggregate density. We demonstrate that quantifying the peritumoral lymphocytic presence is not only associated with associated with better prognosis, but along with TILs within the tumor, adds additional prognostic value in the absence of well-known second mutations including TERT. Annotations of peritumoral lymphoid aggregates on 171 well-differentiated PTCs in the TCGA-THCA dataset were used to train a deep-learning model to predict regions of lymphoid aggregates across the entire tissue. The fractional area of the tissue regions covered by these lymphocytes was dichotomized to determine two risk groups: significant and low density of peritumoral lymphocytes. DFS prognosticated using these risk groups via Kaplan-Meier (KM) analysis revealed a hazard ratio (HR)=2.51 (95% confidence interval (CI): 2.36, 2.66), tested on 170 new patients also from the TCGA-THCA dataset. The prognostic performance of peritumoral lymphocyte aggregate density were compared against univariate KM analysis of DFS using the fractional area of intratumoral lymphocytes within the primary tumor with HR = 2.04 (95% CI: 1.89, 2.19). Combining the lymphocyte features in and around the tumor yielded a statistically significantly improvement in prognostic performance (HR = 3.17 (95% CI: 3.02, 3.32)) on training and were independently evaluated against 62 patients outside TCGA-THCA with HR = 2.44 (95% CI: 2.19, 2.69). Multivariable Cox-regression analysis on the validation set revealed that the density of peritumoral and intratumoral lymphocytes were prognostic independent of histological subtype with a C-index = 0.815.

Lymphocyte Function in Tertiary Lymphoid Structures Predicts Hepatocellular Carcinoma Outcome

An increasing number of studies have revealed a correlation between tertiary lymphoid structures (TLSs) and the outcome of hepatocellular carcinoma (HCC). Nevertheless, the associations between the heterogeneity of cellular composition and the overall survival (OS) in HCC remain unexplored. Here, we evaluated the cancer tissues from 150 HCC individuals treated at the Tumor Hospital Affiliated with Nantong University using multiplex immunofluorescence to determine the presence and characteristics of TLS and to investigate the relationship between intra-TLS immunologic activity, TLS maturation, and intratumoral immune cell infiltration. Prognostic factors influencing the outcome were identified through both univariate and multivariate analyses. Additionally, the levels of cytotoxic T-lymphocyte antigen-4 (CTLA-4), programmed death 1, programmed death-ligand 1, and lymphocyte activation gene-3 were determined, as well as their relationship with TLS features were determined. TLS was detected in 71 (47.3%) of the 150 HCC cases and was related to higher intratumoral infiltration levels of lymphocytes. Additionally, intra-TLS lymphocyte proliferation correlated with that of intratumoral lymphocytes, and the presence of TLS and a high proportion of mature TLS demonstrated a significant correlation with better prognosis (P = .013 and P = .03, respectively). Among TLS-positive tumors, a high proportion of B cells expressing activation-induced cytidine deaminase and a high proportion of CD8+ T cells expressing CD45RO were significantly related to improved OS (P = .01 and P < .001, respectively). Comparatively, a high proportion of CD21+CD20+ B cells demonstrated a significant correlation with poorer OS (P < .002). A markedly reduced number of CTLA-4+ cells in the stromal regions in TLS-negative tumors was observed compared with TLS-positive tumors (P = .01). These findings reveal a correlation between TLS presence and improved OS in HCC patients. However, TLS exhibited significant variation in maturation state, T- and B-cell proliferation, and expression of markers related to B- and T-cell function. Notably, these characteristics were also found to possess prognostic significance, indicating that certain TLS might hinder tumor immunity by inhibiting immune cells, whereas others may foster antigen-driven immune responses, likely influenced by the composition and functional status of intra-TLS lymphocytes.

Evaluation of prognostic factors for oral tongue squamous cell carcinoma: Significance of intratumoral tumor-infiltrating lymphocytes, lymph node ratio, and depth of invasion.

132 Background: Oral tongue squamous cell carcinoma (SCC) is an aggressive malignancy with a variable prognosis. Identifying reliable prognostic factors is crucial for developing personalized treatment strategies and improving patient outcomes. This study examined the prognostic significance of clinicopathological factors in oral tongue SCC. Methods: A retrospective cohort study was conducted on 192 patients who underwent surgical resection at Asan Medical Center between 2010 and 2017. Clinicopathological data, including age at diagnosis, American Joint Committee of Cancer (AJCC) 8th edition stages, depth of invasion (DOI), extranodal extension (ENE), intratumoral and stromal (invasive front) tumor-infiltrating lymphocytes (TILs), lymphovascular invasion (LVI), margin status, metastatic-to-examined lymph nodes ratio (LNR), number of metastatic lymph nodes, perineural invasion (PNI), sex, size, tumor budding, tumor differentiation, tumor-to-stromal ratio (TSR), and worst pattern of invasion (WPOI) were analyzed. The total cohort, early-stage group, and late-stage group were analyzed separately. Results: Most variables showed significant associations with the survival rate. The multivariate Cox proportional hazard models for the total cohort showed significant results for intratumoral TILs, DOI grade, and LNR. However, other factors failed to show statistical significance. Intratumoral TIL was the only consistently potent factor for survival in all study groups. Conclusions: Our findings highlight the need for increased focus on the prognostic significance of intratumoral TILs. The DOI grade and LNR were also powerful prognostic factors, especially in late-stage tongue SCCs. Our data suggest that the prognostic significance of certain variables, such as the WPOI, may have been overestimated in the literature, thereby warranting a reassessment of the currently utilized prognostic markers in oral tongue SCC.

T cell receptor clonotype in tumor microenvironment contributes to intratumoral signaling network in patients with colorectal cancer.

Single-cell RNA sequencing (scRNA-seq) has contributed to understanding cellular heterogeneity and immune profiling in cancer. The aim of the study was to investigate gene expression and immune profiling in colorectal cancer (CRC) using scRNA-seq. We analyzed single-cell gene expression and T cell receptor (TCR) sequences in 30 pairs of CRC and matched normal tissue. Intratumoral lymphocytes were measured with digital image analysis. CRC had more T cells, epithelial cells, and myeloid cells than normal colorectal tissue. CRCs with microsatellite instability had more abundant T cells than those without microsatellite instability. Immune cell compositions of CRC and normal colorectal tissue were inversely correlated. CD4 + or CD8 + proliferating T cells, CD4 + effector memory T cells, CD8 + naïve T cells, and regulatory T cells of CRC showed higher TCR clonal expansion. Tumor epithelial cells interacted with immune cells more strongly than normal. T cells, myeloid cells, and fibroblasts from CRCs of expanded T cell clonotypes showed increased expression of genes related to TNF and NFKB signaling and T cell activation. CRCs of expanded T cell clonotypes also showed stronger cellular interactions among immune cells, fibroblasts, and endothelial cells. Pro-inflammatory CXCL and TNF signaling were activated in CRCs of expanded T cell clonotype. In conclusion, scRNA-seq analysis revealed different immune cell compositions, differential gene expression, and diverse TCR clonotype dynamics in CRC. TCR clonality expansion is associated with immune activation through T cell signaling and chemokine signaling. Patients with CRCs of expanded clonotype can be promising candidates for immunotherapy.

Tumor microenvironment responsive nano-herb and CRISPR delivery system for synergistic chemotherapy and immunotherapy

Chemoresistance remains a significant challenge for effective breast cancer treatment which leads to cancer recurrence. CRISPR-directed gene editing becomes a powerful tool to reduce chemoresistance by reprogramming the tumor microenvironment. Previous research has revealed that Chinese herbal extracts have significant potential to overcome tumor chemoresistance. However, the therapeutic efficacy is often limited due to their poor tumor targeting and in vivo durability. Here we have developed a tumor microenvironment responsive nanoplatform (H-MnO2(ISL + DOX)-PTPN2@HA, M(I + D)PH) for nano-herb and CRISPR codelivery to reduce chemoresistance. Synergistic tumor inhibitory effects were achieved by the treatment of isoliquiritigenin (ISL) with doxorubicin (DOX), which were enhanced by CRISPR-based gene editing to target protein tyrosine phosphatase non-receptor type 2 (PTPN2) to initiate long-term immunotherapy. Efficient PTPN2 depletion was observed after treatment with M(I + D)PH nanoparticles, which resulted in the recruitment of intratumoral infiltrating lymphocytes and an increase of proinflammatory cytokines in the tumor tissue. Overall, our nanoparticle platform provides a diverse technique for accomplishing synergistic chemotherapy and immunotherapy, which offers an effective treatment alternative for malignant neoplasms.Graphical

The Comprehensive Characterization of B7-H3 Expression in the Tumor Microenvironment of Lung Squamous Cell Carcinoma: A Retrospective Study.

Lung squamous cell carcinoma (LSCC) is refractory to various therapies for non-small cell cancer; therefore, new therapeutic approaches are required to improve the prognosis of LSCC. Although immunotherapies targeting B7 family molecules were explored as treatments for several cancer types, the expression and significance of B7-H3 in the tumor microenvironment (TME) and its relationship with other immune checkpoint molecules have not yet been investigated in detail. We used high-throughput quantitative multiplex immunohistochemistry to examine B7-H3 expression in the TME. We investigated the relationship between B7-H3 expression and prognosis as well as changes in the TME with B7-H3 expression using 110 surgically resected pathological specimens retrospectively. We examined the correlation between B7-H3 and programmed cell death-ligand 1 (PD-L1) expression in single cells. High B7-H3 expression in tumor cells was associated with a better prognosis and a significant increase in the number of CD163+PD-L1+ macrophages. Quantitative analysis revealed that there is a positive correlation between B7-H3 and PD-L1 expression in tumor and stromal cells, as well as in intratumoral tumor-infiltrating lymphocytes and tumor-associated macrophages in the same cells. CD68+, CD163+, and CK+ cells with PD-L1+ phenotypes had higher B7-H3 expression compared to PD-L1- cells. Our findings demonstrate a correlation between B7-H3 and PD-L1 expression in the same cells, indicating that therapies targeting B7-H3 could provide additional efficacy in patients refractory to PD-L1-targeting therapies.

Evaluation of the immune landscape associated with the efficacy of immunotherapy in patients with triple-negative breast cancer: Starlet study, synergy between research and clinical work.

e12568 Background: Neoadjuvant chemotherapy (NACT) is the standard treatment for early-stage TNBC and achieving a pathological complete response (pCR) is an essential prognostic factor. Recently, by applying a morphology-guided spatial transcriptomic approach, we showed that intratumoral infiltrating lymphocytes (iTILs) and stromal Natural Killer (NK) cells are major determinants of chemotherapy efficacy in TNBC. These data underline how spatiality and molecular activation of immune cells are essential to enhance the efficacy of the NACT in TNBC. The fact that immune cells are important players in this setting is corroborated by the clinical success showed by the KEYNOTE-522 study (Schmid et al, NEJM 2020). This trial paved the way for the use of immunotherapy in TNBC, obtaining a significant improvement in the patient’s overall response. The implementation of chemotherapy with immunotherapy in the TNBC neoadjuvant treatment implicates several compelling questions, including how to further increase the percentage of pCR overcoming resistance mechanisms and how to improve the personalization of treatment, evaluating which patients can benefit from a therapy de-scalation or another combined therapeutic strategy. Methods: we enrolled 43 patients with early-TNBC treated with the KEYNOTE-522 regimen. To further clarify the immune dynamics that lead to a complete response to pembrolizumab in these patients, we collected peripheral blood before and after neoadjuvant treatment to isolate peripheral blood mononucleated cells (PBMCs). We applied asingle-cell transcriptome analysis to shape any variations in circulating immune cells occurring during neoadjuvant treatment and associated with patient response. In addition, we collected residual tumor at surgery from partial responders and derived three-dimensional organoids that recapitulate the characteristics of patient tumor. Results: Immune profiling of PBMCs indicated that patients showing pCR during NACT and immunotherapy displayed a decrease of B Lymphocytes and a concomitant enhancement of Natural Killers. We successfully established TNBC patient-derived organoids from 8 TNBC patients. Conclusions: our ongoing study is defining the immune-related molecular mechanisms driving pembrolizumab and chemotherapy response in the neoadjuvant treatment of TNBC patients. Our findings can improve our understanding of which immune populations are determinant players in anti-TNBC immune response and can be proposed as novel biomarkers of pembrolizumab efficacy during the neoadjuvant treatment.

Abstract PO2-25-03: Deciphering the immune molecular signature associated with pembrolizumab efficacy in the neoadjuvant setting of Triple-Negative Breast Cancer patients: a single-centre experience

Abstract Triple-negative breast cancer (TNBC) accounts for 15-20% of all breast cancers and is characterized by a high rate of recurrence, despite the improvement of the therapeutic approaches in recent years. Neoadjuvant chemotherapy (NACT) is the standard treatment for early-stage TNBC. Achieving a pathological complete response (pCR) is considered an essential prognostic factor for long-term outcomes. However, the percentage of pCR patients after NACT is limited to 30-40%, thus requiring the implementation of novel therapeutic strategies. Recently, by applying a morphology-guided spatial transcriptomic approach on Tru-Cut biopsies, we showed that intratumoral infiltrating lymphocytes (iTILs) and stromal Natural Killer (NK) cells are major determinants of chemotherapy efficacy in TNBC. These data highlight a complex three-dimensional organization of the tumor landscape and underline how spatiality and molecular activation of immune cells are essential to enhance the efficacy of neoadjuvant NACT in TNBC. The fact that immune cells are important players in this setting is corroborated by the clinical success shown by the KEYNOTE-522 study. This trial paved the way for the use of immunotherapy in neoadjuvant settings, obtaining a significant improvement in the patient’s overall response compared to standard NACT. Still, the implementation of chemotherapy with immunotherapy in the TNBC neoadjuvant treatment implicates several compelling questions, including how to further increase the percentage of patients with a complete response, overcoming resistance mechanisms, and how to improve the personalization of treatment, evaluating which patients can benefit from a therapy de-scalation or another combined therapeutic strategy. In this prospective cohort study, we decided to define the relevance of different immune populations in affecting pembrolizumab efficacy in the neoadjuvant treatment of TNBC patients. We treated 40 patients with an early-TNBC diagnosis with the KEYNOTE-522 regimen that consists of four cycles of an intravenous infusion of pembrolizumab plus paclitaxel and carboplatin, followed by four cycles of pembrolizumab plus epirubicin and cyclophosphamide. Only patients with evident side effects to immunotherapy administration were a priori excluded. Currently, 18 patients ended the neoadjuvant schedule and underwent surgical excision. Our data indicate that 15 patients displayed a pCR at the end of the therapy, whereas 3 patients displayed only partial response. To further clarify the immune dynamics that lead to a complete response to pembrolizumab in these patients, we collected peripheral blood before and after neoadjuvant treatment to isolate peripheral blood mononucleated cells (PBMCs). We applied a single-cell transcriptome analysis to shape any variations in circulating immune cells occurring during neoadjuvant treatment and associated with patient response. In addition, we collected residual tumors at surgery from partial responders and derived three-dimensional organoids that recapitulate the characteristics of the original patient tumor. These ex vivo organoid-based platforms are applied to clarify the molecular mechanisms driving neoadjuvant resistance. To this aim, we are performing co-cultures with autologous immune cells to identify novel combined therapeutic strategies to rescue pembrolizumab efficacy in these models. Overall, our study is defining the immune-related molecular mechanisms driving pembrolizumab and chemotherapy response in the neoadjuvant treatment of TNBC patients. Our findings can improve our understanding of which immune populations are determinant players in anti-TNBC immune response and can be proposed as novel biomarkers of pembrolizumab efficacy during the neoadjuvant treatment. Citation Format: Elisa Gasparini, Gloria Manzotti, Moira Ragazzi, Benedetta Donati, Federica Torricelli, Elisa Salviato, Alessandra Bisagni, Eleonora Zanetti, Alessandra Bologna, Saverio Coiro, Rita Vacondio, Guglielmo Ferrari, Giancarlo Bisagni, Carmine Pinto, Alessia Ciarrocchi, Francesca Reggiani. Deciphering the immune molecular signature associated with pembrolizumab efficacy in the neoadjuvant setting of Triple-Negative Breast Cancer patients: a single-centre experience [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-25-03.

Prognostic Value of "Basal-like" Morphology, Tumor-Infiltrating Lymphocytes and Multi-MAGE-A Expression in Triple-Negative Breast Cancer.

"Basal-like" (BL) morphology and the expression of cancer testis antigens (CTA) in breast cancer still have unclear prognostic significance. The aim of our research was to explore correlations of the morphological characteristics and tumor microenvironment in triple-negative breast carcinomas (TNBCs) with multi-MAGE-A CTA expression and to determine their prognostic significance. Clinical records of breast cancer patients who underwent surgery between January 2017 and December 2018 in four major Croatian clinical centers were analyzed. A total of 97 non-metastatic TNBCs with available tissue samples and treatment information were identified. Cancer tissue sections were additionally stained with programmed death-ligand 1 (PD-L1) Ventana (SP142) and multi-MAGE-A (mAb 57B). BL morphology was detected in 47 (49%) TNBCs and was associated with a higher Ki-67 proliferation index and histologic grade. Expression of multi-MAGE-A was observed in 77 (79%) TNBCs and was significantly associated with BL morphology. Lymphocyte-predominant breast cancer (LPBC) status was detected in 11 cases (11.3%) and significantly correlated with the Ki-67 proliferation index, increased number of intratumoral lymphocytes (itTIL), and PD-L1 expression. No impact of BL morphology, multi-MAGE-A expression, histologic type, or LPBC status on disease-free survival was observed. Our data suggest that tumor morphology could help identify patients with potential benefits from CTA-targeting immunotherapy.

Emerging measurements for tumor-infiltrating lymphocytes in breast cancer.

Tumor-infiltrating lymphocytes are a general term for lymphocytes or immune cells infiltrating the tumor microenvironment. Numerous studies have demonstrated tumor-infiltrating lymphocytes to be robust prognostic and predictive biomarkers in breast cancer. Recently, immune checkpoint inhibitors, which directly target tumor-infiltrating lymphocytes, have become part of standard of care treatment for triple-negative breast cancer. Surprisingly, tumor-infiltrating lymphocytes quantified by conventional methods do not predict response to immune checkpoint inhibitors, which highlights the heterogeneity of tumor-infiltrating lymphocytes and the complexity of the immune network in the tumor microenvironment. Tumor-infiltrating lymphocytes are composed of diverse immune cell populations, including cytotoxic CD8-positive T lymphocytes, B cells and myeloid cells. Traditionally, tumor-infiltrating lymphocytes in tumor stroma have been evaluated by histology. However, the standardization of this approach is limited, necessitating the use of various novel technologies to elucidate the heterogeneity in the tumor microenvironment. This review outlines the evaluation methods for tumor-infiltrating lymphocytes from conventional pathological approaches that evaluate intratumoral and stromal tumor-infiltrating lymphocytes such as immunohistochemistry, to the more recent advancements in computer tissue imaging using artificial intelligence, flow cytometry sorting and multi-omics analyses using high-throughput assays to estimate tumor-infiltrating lymphocytes from bulk tumor using immune signatures or deconvolution tools. We also discuss higher resolution technologies that enable the analysis of tumor-infiltrating lymphocytes heterogeneity such as single-cell analysis and spatial transcriptomics. As we approach the era of personalized medicine, it is important for clinicians to understand these technologies.

Abstract 4064: hetIL-15 and Fenofibrate combination alters the metabolic fitness of tumor-infiltrating CD8+T cells leading to TNBC tumor eradication in mice

Abstract Introduction: Tumor-infiltrating cytotoxic CD8+T cells frequently undergo an altered state of differentiation referred to as "exhaustion" and, as a result, they fail to control tumor growth. IL-15 is a cytokine which stimulates the generation, proliferation and cytotoxic function of tumor CD8+T and NK cells. We have produced the native heterodimeric form of IL-15 (hetIL-15) which has advanced in clinical trials. The aim of this study was to overcome the exhaustion of the tumor-infiltrating CD8+T cells and to increase their cytotoxicity, using Fenofibrate (FF), a PPAR-α agonist, in combination with hetIL-15. Experimental Procedures: We have evaluated the therapeutic efficacy of hetIL-15 immunotherapy as a monotherapy and in combination with FF in the murine EO771 orthotopic breast cancer model. The effects of hetIL-15 and/or FF on immune cells and on tumor microenvironment were analyzed by flow cytometry, transcriptomics, metabolomics and proteomics. The metabolic profile of tumor-infiltrating T cells was performed with Seahorse analysis. Results and Conclusions: hetIL-15 monotherapy resulted in tumor eradication in 40% of treated mice and increased survival. Seahorse analysis of tumor-infiltrating CD8+T cells confirmed a rise in oxygen consumption rate (OCR) with substantial increase of spare respiratory capacity. Upon hetIL-15 treatment, tumor-infiltrating CD8+T cells showed elevated extracellular acidification rate (ECAR), resulting in a pronounced shift in the OCR/ECAR ratio in comparison to control, confirming their increased proliferating status. These tumor-infiltrating CD8+T cells also showed increased mitochondrial potential and/or mass and fatty acid (FA) uptake, as evidenced by increased MitoTracker and Bodipy staining, respectively. Transcriptomic analysis revealed increased expression of genes involved in several metabolic pathways such as oxidative phosphorylation, FA oxidation and glycolysis. Monotherapy with FF had no effect on tumor growth delay, whereas the FF- hetIL-15 combination resulted in complete eradication of the tumors in 85%. Combination therapy reshaped the tumor microenvironment, resulting in higher IFN-γ and in differentially expressed metabolites as shown by tumor proteomics and metabolomics, respectively. The combination treatment increased the mitochondrial function, FA uptake and OCR, revealing a more metabolically active phenotype. We conclude that hetIL-15 supports a favorable metabolic profile of intratumoral effector lymphocytes, important for their function. Our data suggest that metabolic reprogramming of tumor specific CD8+T cells using FF is a promising strategy to overcome T cell exhaustion and to promote survival in a metabolically hostile tumor microenvironment. Citation Format: Dimitris Stellas, Sevasti Karaliota, Vasiliki Stravokefalou, Katherine C. Goldfarbmuren, Breana Myers, George N. Pavlakis, Barbara K. Felber. hetIL-15 and Fenofibrate combination alters the metabolic fitness of tumor-infiltrating CD8+T cells leading to TNBC tumor eradication in mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4064.

Abstract 1048: Loss of MTAP expression is strongly linked to homozygous 9p21 deletion, unfavorable tumor phenotype and non-inflamed microenvironment in urothelial bladder cancer

Abstract 9p21 deletions are common in urothelial carcinoma and mostly include S-methyl-5′-thioadenosine phosphorylase (MTAP) a critical enzyme for DNA and RNA synthesis. Homozygous MTAP deletions result in a complete loss of expression which can be visualized by immunohistochemistry (IHC). Evidence is emerging that MTAP deficiency results in a critical vulnerability of cancer cells towards drugs targeting multiple different pathways that depend on a functional MTAP gene and causes resistance to immune checkpoint inhibitors. To determine the prevalence and clinical significance of MTAP deficiency and its relationship with the tumor microenvironment in urothelial bladder carcinomas, more than 2,500 tumors were analyzed by fluorescence in-situ hybridization (FISH) and IHC in a tissue microarray format, and the data were compared with existing data on intratumoral lymphocyte subsets and PD-L1 expression. The cohort included 1,826 patients that underwent radical cystectomy for muscle-invasive disease (pT2-4). 9p21 deletion was homozygous in 364 (21.3%) and heterozygous in 334 (19.5%) of 1,711 analyzable tumors. The rate of 9p21 deleted tumors increased from pTa G2 low (9.2% homozygous, 25.8% heterozygous) to pTa G2 high (32.6%, 20.9%; p&amp;lt;0.0001) but was slightly lower in pTa G3 (16.7% each). In pT2-pT4 carcinomas, 9p21 deletions were homozygous in 23.3% and heterozygous in 17.9%. Within muscle-invasive cancers, 9p21 deletions were tied to high pT (p=0.0014) and poor overall survival (p=0.0461). MTAP expression loss was strongly linked to homozygous 9p21 deletions. Complete absence of MTAP staining was seen in 96.1% of homozygous deleted cancers while only 4 of 249 MTAP negative cancers had retained at least one 9p21 copy (p&amp;lt;0.0001). Accordingly, absence of MTAP staining was also linked to advanced pT status and poor overall survival (p&amp;lt;0.05 each). Tumors with heterozygous 9p21 deletion did often show preserved but low-level expression of MTAP. 9p21 deletions were associated with low numbers of PD-L1 positive tumor cells (p&amp;lt;0.0001), CD8 (p=0.01) and CD4 positive lymphocytes (p=0.009), M2-macrophages (p&amp;lt;0.0001), and dendritic cells (p=0.0007). A similar tendency was observed for MTAP expression loss, but the level of significance was only reached for PD-L1 positive tumor cells (p&amp;lt;0.0001), M2 macrophages (p=0.001) and dendritic cells (p=0.012). Complete MTAP expression loss is common in urinary bladder cancer and strongly tied to homozygous 9p21 loss, aggressive disease, and non-inflamed microenvironment. Drugs targeting MTAP-deficiency may be highly useful in bladder cancer. MTAP IHC is an excellent surrogate for the detection of MTAP deficiency in this tumor entity. Citation Format: Natalia Gorbokon, Niklas Wößner, Viktoria Ahlburg, Simon Schallenberg, Henning Plage, Sebastian Hofbauer, Kira Furlano, Sarah Weinberger, Paul G. Bruch, Florian Roßner, Sefer Elezkurtaj, Maximilian Lennartz, Niclas C. Blessin, Andreas H. Marx, Henrik Samtleben, Margit Fisch, Michael Rink, Marcin Slojewski, Krystian Kaczmarek, Thorsten Ecke, Steffen Hallmann, Stefan Koch, Nico Adamini, Sarah Minner, Ronald Simon, Guido Sauter, Henrik Zecha, David Horst, Tobias Klatte, Thorsten Schlomm, Martina Kluth. Loss of MTAP expression is strongly linked to homozygous 9p21 deletion, unfavorable tumor phenotype and non-inflamed microenvironment in urothelial bladder cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1048.

Abstract B014: Immuno-modulation of the tumor microenvironment of pancreatic adenocarcinoma following isotoxic high-dose stereotactic body radiotherapy (iHD-SBRT)

Abstract INTRODUCTION: Pancreatic ductal adenocarcinoma (PDAC) remains one of the deadliest tumors. Unlike other tumors, the progress of systemic therapies has been very slow, mainly due to the peculiar and resistant tumor microenvironment (TME) of PDAC. The addition of ablative stereotactic body radiation therapy (SBRT) in a total neoadjuvant strategy is promising for the treatment of localized PDAC and is currently being explored in several clinical trials. However, if radiation therapy possesses the ability to modulate the TME, the impact of high-dose SBRT is still poorly known in PDAC. Here, we aim to characterize by immunohistochemistry (IHC) and RNA sequencing (RNAseq) analysis the immuno-modulations of the TME following isotoxic high-dose stereotactic body radiotherapy (iHD-SBRT). MATERIAL: Paraffin-embedded residual tumoral tissues of 50 localized PDAC resected between 2011 and 2020 were used: seventeen patients had surgery first, seventeen received an induction chemotherapy with FOLFIRINOX (FFX) only and sixteen with FFX followed by an iHD-SBRT designed to individually maximize the dose prescribed to the tumor and vessels interfaces up to Dmax(0.5cc)&amp;lt;53Gy in 5 fractions. RESULTS: We found that although collagen deposition increases significantly after iHD-SBRT (COL1: 83.27 vs 78.60 vs 68.04%, p&amp;lt;0.001 for iHD-SBRT, FFX and treatment naïve cohort respectively), the intra-tumoral lymphocyte infiltration is globally not altered, including for cytotoxic CD8+ lymphocytes. Only the IHC expression of CD4+ T helper population is significantly decreased after iHD-SBRT. Using gene set enrichment analysis (GSEA) of the KEGG pathway, the IL-17 signaling pathway related to the T17 cells is particularly significantly increased after iHD-SBRT compared to FFX only. After iHD-SBRT, the IHC expression levels of FOXP3+ cells and PD-L1 are significantly increased. No difference is observed for CD68+ expression however, cell type enrichment analysis from our RNA-seq data using xCell algorithm shows that the M2-polarized CD68+ cells are increased after iHD-SBRT compared to FFX alone. PD-1 expression is significantly decreased after iHD-SBRT. Furthermore, RNAseq data revealed that iHD-SBRT is associated with significant enrichment in basaloid cells (p&amp;lt;0.0024), a subtype of basal–like cells associated with immunomodulatory stroma and better clinical outcomes. GSEA canonical pathway analysis further revealed metabolism-related pathways such as oxidative phosphorylation and gluthathione metabolism significantly enriched in iHD-SBRT treated group, suggesting the potential of mitochondrial inhibitors as candidates for combination therapy. CONCLUSIONS: iHD-SBRT is able to durably immuno-modulate the TME of PDAC. If the overall T-cell infiltration is preserved, we have identified some increased pro-tumoral cells and pathways after iHD-SBRT that could improve the development of better-oriented combination trials involving high-dose SBRT. Citation Format: Christelle Bouchart, Oier Azurmendi Senar, Julie Navez, Laurine Verset, Anaïs Boisson, Matthieu Hein, Nicky D’Haene, Dirk Van Gestel, Luigi Moretti, Pieter Demetter, Jean-Baptiste Bachet, Karen Willard-Gallo, Rémy Nicolle, Tatjana Arsenijevic, Jean-Luc Van Laethem. Immuno-modulation of the tumor microenvironment of pancreatic adenocarcinoma following isotoxic high-dose stereotactic body radiotherapy (iHD-SBRT) [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr B014.

Genomic and Immunophenotypic Landscape of Acquired Resistance to PD-(L)1 Blockade in Non-Small-Cell Lung Cancer.

Although immune checkpoint inhibitors (ICI) have extended survival in patients with non-small-cell lung cancer (NSCLC), acquired resistance (AR) to ICI frequently develops after an initial benefit. However, the mechanisms of AR to ICI in NSCLC are largely unknown. Comprehensive tumor genomic profiling, machine learning-based assessment of tumor-infiltrating lymphocytes, multiplexed immunofluorescence, and/or HLA-I immunohistochemistry (IHC) were performed on matched pre- and post-ICI tumor biopsies from patients with NSCLC treated with ICI at the Dana-Farber Cancer Institute who developed AR to ICI. Two additional cohorts of patients with intervening chemotherapy or targeted therapies between biopsies were included as controls. We performed comprehensive genomic profiling and immunophenotypic characterization on samples from 82 patients with NSCLC and matched pre- and post-ICI biopsies and compared findings with a control cohort of patients with non-ICI intervening therapies between biopsies (chemotherapy, N = 32; targeted therapies, N = 89; both, N = 17). Putative resistance mutations were identified in 27.8% of immunotherapy-treated cases and included acquired loss-of-function mutations in STK11, B2M, APC, MTOR, KEAP1, and JAK1/2; these acquired alterations were not observed in the control groups. Immunophenotyping of matched pre- and post-ICI samples demonstrated significant decreases in intratumoral lymphocytes, CD3e+ and CD8a+ T cells, and PD-L1-PD1 engagement, as well as increased distance between tumor cells and CD8+PD-1+ T cells. There was a significant decrease in HLA class I expression in the immunotherapy cohort at the time of AR compared with the chemotherapy (P = .005) and the targeted therapy (P = .01) cohorts. These findings highlight the genomic and immunophenotypic heterogeneity of ICI resistance in NSCLC, which will need to be considered when developing novel therapeutic strategies aimed at overcoming resistance.

CD8-Lymphocytic Phenotype Significance in Primary Multiple and Familial Melanoma with Various CDKN2A Mutational Status.

Background and Objectives: In the realm of the rising incidence of cutaneous and mucous melanoma, CDKN2A mutations characterize familial and multiple primary melanoma cases. The involvement of tumor-infiltrating lymphocytes (TILs) is interconnected with survival rates, but may extend even further. The aim of this study is to verify the accuracy of the classical "naked eye" count of CD8-positive T cells comprised within the tumoral population and peritumoral infiltrate versus that obtained via a special software run by the aid of artificial intelligence (AI), used to determine the percentage of CD8-positive TILs. Materials and Methods: The present retrospective cross-sectional study conducted over a period of 5 years (2018-2022) focused on patients diagnosed with mucous and/or cutaneous melanoma, with a positive family history for melanoma, or personal antecedents of primary malignant melanocytic lesions. The 23 selected cases were diagnosed histopathologically, tested for CDKN2A mutations through fluorescent hybridization in situ, and CD8 immunohistochemistry was performed. The included slides were evaluated both manually (naked-eye examination) and automatically (via QuPath platform) for quantifying the CD8-positive TILs. Results: The number of CD8-positive TILs in melanoma samples has been more accurately identified through the use of an AI-mediated software as compared to the human-eye evaluation performed by experimental pathologists. A higher percentage of CD8-positive intratumoral lymphocytes versus stromal lymphocytes was positively associated with more numerous metastatic sites. Conclusions: The CD8 lymphocytic phenotype harbors major significance in the context of familial and multiple primary melanoma and may comprise a cost-effective investigation meant to help in the establishment of melanoma prognosis and response to immunotherapy.

Prognostic Significance of the Neutrophil/Lymphocyte Ratio in Diffuse Large B-Cell Lymphoma: A Systematic Review and Meta-Analysis

PROGNOSTIC SIGNIFICANCE OF THE NEUTROPHIL/LYMPHOCYTE RATIO IN DIFFUSE LARGE B-CELL LYMPHOMA: A SYSTEMATIC REVIEW AND META-ANALYSIS BACKGROUND: The neutrophil-lymphocyte ratio (NLR) has stunned up as an easy to use prognostic biomarker in different cancers. Although the exact mechanism remains to be elucidated, reduced infiltration of intratumoral lymphocytes along with the development of neutrophil extracellular traps (i.e., NETosis) has been postulated as endogenous mechanisms for tissue damage and inflammation. We previously reported a NLR ≥4 as independently associated to inferior complete response rates to chemoimmunotherapy and worse survival in Latin American (LATAM) patients with diffuse large B-cell lymphoma (DLBCL; Beltran, Clin Lymphoma Myeloma Leuk, 2020). Here we present a systematic review and meta-analysis on the prognostic value of the NLR in DLBCL. METHODS: A systematic search was conducted using PUBMED, EMBASE and SCOPUS databases up to the most recent date (October 2022). Prospective and retrospective cohorts were reviewed using the diagnosis of DLBCL according to the WHO criteria. The NLR was defined as the ratio between absolute neutrophil and lymphocyte counts in peripheral blood prior to initiating therapy. Two independent reviewers selected the studies and subsequently extracted the data. Clinical variables included gender, age, tumor stage, IPI, presence of B symptoms, serum LDH level, extranodal location, ECOG performance status, treatment regimen, NLR value, Hazard Ratio with its respective 95% confidence interval (CI). Once the quality of the extracted data was verified, a quantitative synthesis of the information was conducted through a meta-analysis-based approach. Additionally, a sensitivity analysis was performed using the leave-one-out method and a NLR cut-off of &amp;gt;4. A meta-regression model was applied to assess the influence of a sample size &amp;lt;200 (based on previous reviews) on the heterogeneity of the results. Primary endpoints were overall survival (OS) and progression-free survival (PFS) rates. Association was reported by Hazard Ratio (HR). Risk of bias was assessed using the Newcastle-Ottawa Scale adapted by Hassan-Murad et al. Data were analyzed using the R program version 4.2.3. RESULTS: Fifteen studies were identified and 4,149 patients were included. Only 3 studies were from Latin America. The median NLR was 4.1 (range 1.5 to 5.54). Thirteen studies with 3,498 patients showed a significant association between NLR and OS (HR: 1.57 [95% CI: 1.3-1.9, I2: 46%; P=0.04]), and 11 studies with 2,660 patients found no association between NLR and PFS (HR: 1.32 [95%CI: 0.8-2.03, I2: 0%; P=0.72]). When reanalyzing the data by region, the NLR was associated to worse OS in Latin American patients (HR: 1.94 [95%CI: 1.14-3.3, I2: 51%; P=0.15]), followed by Europe (HR: 1.79 [95%CI: 1.41-2.27, I2: 0%; P=0.74]) and finally Asia (HR: 1.26 [95% CI: 0.8-1.8, I2: 62%; P=0.02]) Regarding the association between NLR and PFS according to region, Europe (HR: 5.08 [95%CI: 0.7-38, I2: 93%; P&amp;lt;0.001]) and Asia (HR: 1.28 [95CI %: 0.95-1.71, I2: 56%; P=0.03]) did not present an association. We could not perform analysis for Latin America due to only one study was available for analysis. Regarding the cut-off point for NLR, a cut-off of &amp;gt;4 was adversely associated with OS (HR: 1.63 [95%CI: 1.36-1.95, I2: 0%; P=0.46]), and a trend for worse PFS (HR: 1.70 [CI-95%: 1.24-2.33, I2: 51%; P=0.08]). In the sensitivity analysis, when we excluded the results of Jing Wang et al, the heterogeneity disappeared (I2=0%, p&amp;lt;0.01). However, the effect size of the association was not significantly increased (HR: 1.69 [95% CI: 1.46-1.96, I2: 0%; P&amp;lt;0.01]). In the sensitivity analysis for PFS, the results remained stable. The absence of publication bias between studies was confirmed for OS (p= 0.42), but not for PFS (p&amp;lt; 0.0001). A sample size &amp;lt;200 did not influence heterogeneity. DISCUSSION: Our study found the NLT as a relevant prognostic factor for OS in DLBCL patients. The main limitation was the inconsistency of the cut-off values for the NLR in the different studies included, suggesting the need to standardize this cut-off for future research studies. However, a cut-off point &amp;gt;4 could be a promising clinical biomarker for this patient population.

Peritumoral Immune-suppressive Mechanisms Impede Intratumoral Lymphocyte Infiltration into Colorectal Cancer Liver versus Lung Metastases.

Our results demonstrate that functional status and spatial distribution of immune cells vary significantly across different metastatic sites in MSS colorectal cancer. These findings suggest that metastatic site-dependent immune contexture may underlie discordant responses to ICI therapy in patients with MSS colorectal cancer.

Intratumoral Microbiota Changes with Tumor Stage and Influences the Immune Signature of Oral Squamous Cell Carcinoma.

Characterization of the oral microbiota profile through various studies has shown an association between the microbiome and oral cancer; however, stage-specific determinants of dynamic changes in microbial communities of oral cancer remain elusive. Additionally, the influence of the intratumoral microbiota on the intratumoral immune system remains largely unexplored. Therefore, this study aims to stratify microbial abundance in the early-onset and subsequent stages of oral cancer and analyze their influence on clinical-pathological and immunological features. The microbiome composition of tissue biopsy samples was identified using 16S rRNA amplicon sequencing, while intratumoral and systemic immune profiling was done with flow cytometry and immunohistochemistry-based analysis. The bacterial composition differed significantly among precancer, early cancer, and late cancer stages with the enrichment of genera Capnocytophaga, Fusobacterium, and Treponema in the cancer group, while Streptococcus and Rothia were enriched in the precancer group. Late cancer stages were significantly associated with Capnocytophaga with high predicting accuracy, while Fusobacterium was associated with early stages of cancer. A dense intermicrobial and microbiome-immune network was observed in the precancer group. At the cellular level, intratumoral immune cell infiltration of B cells and T cells (CD4+ and CD8+) was observed with enrichment of the effector memory phenotype. Naive and effector subsets of tumor-infiltrating lymphocytes (TILs) and related gene expression were found to be distinctly associated with bacterial communities; most importantly, highly abundant bacterial genera of the tumor microenvironment were either negatively correlated or not associated with the effector lymphocytes, which led to the conclusion that the tumor microenvironment favors an immunosuppressive and nonimmunogenic microbiota. IMPORTANCE The gut microbiome has been explored extensively for its importance in the modulation of systemic inflammation and immune response; in contrast, the intratumoral microbiome is less studied for its influence on immunity in cancer. Given the established correlation between intratumoral lymphocyte infiltration and patient survival in cases of solid tumors, it was pertinent to explore the extrinsic factor influencing immune cell infiltration in the tumor. Modulation of intratumoral microbiota could have a beneficial effect on the antitumor immune response. This study stratifies the microbial profile of oral squamous cell carcinoma starting from precancer to late-stage cancer and provides evidence for their immunomodulatory role in the tumor microenvironment. Our results suggest combining microbiome study with immunological signatures of tumors for their prognostic and diagnostic application.

Mismatch Repair Deficient (dMMR) Colorectal Carcinoma in a Pakistani Cohort: Association With Clinical and Pathological Parameters.

Introduction Microsatellite instability (MSI) is an important pathway in colorectal carcinoma (CRC) pathogenesis. MSI occurs due to mutations in mismatch repair (MMR) genes that include MutL protein homolog 1 (MLH1), postmeiotic segregation increased 2 (PMS2), MutS homolog 2 (MSH2), and MutS homolog 6 (MSH6). CRC with MSI is termed MMR deficient (dMMR) CRC. Conversely, CRC with intact MMR genes is called microsatellite stable (MSS) or MMR proficient (pMMR). In this study, we compared the clinicopathological features of dMMR CRC with pMMR CRC. Methods It was a retrospective study conducted in the Department of Histopathology, Liaquat National Hospital, Karachi, Pakistan, from March 2020 to February 2022, over a duration of twoyears. Biopsy-proven cases of CRC with upfront surgical resection were included in the study. Microscopic examination was performed to evaluate tumor type, grade, and extent of invasion, presence of necrosis, perineural invasion (PNI), lymphovascular invasion (LVI), peritumoral lymphocytes (PTL), intratumoral lymphocytes (ITL), and nodal metastasis. Immunohistochemical staining was performed using antibodies, namely, MLH1, PMS2, MSH2, and MSH6. Any loss of nuclear expression in tumor cells was termed dMMR or microsatellite instable, whereas the intact nuclear expression in tumor cells was labeled as MSS or pMMR. Results A total of 135 cases of CRC were included in the study. The mean age at diagnosis was 46.76 ± 17.74 years, with female predominance (60.7%). The loss of MLH1, PMS2, MSH2, and MSH6 expression was noted in 39.3%, 34.1%, 17.8%, and 16.3% cases, respectively. Overall, 59.3% of CRCs were pMMR, while 40.7% were dMMR. A significant association of MMR status was noted with respect to age, PNI, LVI, tumor grade, tumor (T) and nodal (N) stage, mucinous differentiation, and ITL. dMMR CRC was significantly above 50 years than pMMR CRC. The frequency of PNI and LVI was lower in dMMR CRC than in pMMR CRC. Conversely, the higher grade (grade 3) and higher T-stage (T4) were associated with dMMR CRC. Alternatively, the frequency of higher N stage (N2b) was more commonly seen in pMMR CRC. Moreover, mucinous differentiation and ITL were significantly associated with dMMR CRC. Conclusion A significant proportion of CRC patients in our population demonstrated dMMR status. dMMR CRC had a higher histological grade with a higher frequency of mucinous differentiation and higher T-stage. Conversely, the presence of LVI, PNI, and higher N stages were associated with pMMR CRC.

DNA Damage Repair Pathways in Prostate Cancer: A Narrative Review of Molecular Mechanisms, Emerging Biomarkers and Therapeutic Targets in Precision Oncology.

Prostate cancer (PCa) has a distinct molecular signature, including characteristic chromosomal translocations, gene deletions and defective DNA damage repair mechanisms. One crucial pathway involved is homologous recombination deficiency (HRD) and it is found in almost 20% of metastatic castrate-resistant PCa (mCRPC). Inherited/germline mutations are associated with a hereditary predisposition to early PCa development and aggressive behavior. BRCA2, ATM and CHECK2 are the most frequently HRD-mutated genes. BRCA2-mutated tumors have unfavorable clinical and pathological characteristics, such as intraductal carcinoma. PARP inhibitors, due to the induction of synthetic lethality, have been therapeutically approved for mCRPC with HRD alterations. Mutations are detected in metastatic tissue, while a liquid biopsy is utilized during follow-up, recognizing acquired resistance mechanisms. The mismatch repair (MMR) pathway is another DNA repair mechanism implicated in carcinogenesis, although only 5% of metastatic PCa is affected. It is associated with aggressive disease. PD-1 inhibitors have been used in MMR-deficient tumors; thus, the MMR status should be tested in all metastatic PCa cases. A surrogate marker of defective DNA repair mechanisms is the tumor mutational burden. PDL-1 expression and intratumoral lymphocytes have ambivalent predictive value. Few experimental molecules have been so far proposed as potential biomarkers. Future research may further elucidate the role of DNA damage pathways in PCa, revealing new therapeutic targets and predictive biomarkers.