Abstract Despite their long half-life, therapeutic antibodies are considered ineffective against intracellular antigens due to their perceived inability to penetrate epithelial cells. Using recombinant antibodies targeting common mutations in oncogenes, we have demonstrated that dimeric IgA, but not the same antibody on an IgG backbone, penetrates human epithelial cancer cells through PIGR-dependent directional transcytosis, specifically neutralizing mutated oncodrivers and expelling antigens outside the cell, bound to secretory IgA. Accordingly, targeting of KRASG12D abrogated tumor cell proliferation in cell culture assays. In vivo, KRASG12D-specific dIgA1 limited the growth of RASG12D-mutated ovarian and lung carcinomas, including in syngeneic tumor-bearing immunocompetent mice. Moreover, dIgA targeting of KRASG12D restricted tumor growth more effectively than small-molecule KRASG12D inhibitors, supporting the potential of this approach for the treatment of human cancers. Since producing dimeric IgA is more challenging than producing monomeric IgG, and because the half-life of IgA is shorter (4-7 days) than IgG (21 days), we have developed a new approach combining KRASG12D specific IgG with a peptide that could join PIGR and penetrates tumor cells through transcytosis, that showed the same effect than IgA controlling tumor growth. Our results provide a rationale for developing modified IgG cell-penetrating antibodies to effectively target common mutations in intracellular oncogenes that drive many aggressive and frequent human cancers. In addition, further experiments suggest that these antibodies could be effectively used to target tumors that have become resistant to existing KRAS inhibitors. Citation Format: Carmen Maria Anadon Galindo, Luis U. Lopez-Bailon, Ricardo A. Chaurio, Jessica A. Mine, Noah E. Plappert, Jose R. Conejo-Garcia. IgG engineered to target PIGR-mediated transcytosis specifically targets intracellular oncoproteins and abrogated tumor growth [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 6346.

In immuno-oncology, the focus has traditionally been on αβ T cells, and immune checkpoint inhibitors that primarily target PD-1 or CTLA4 in these lymphocytes have revolutionized the management of multiple human malignancies. However, recent research highlights the crucial role of B cells and the antibodies they produce in antagonizing malignant progression, offering new avenues for immunotherapy. Our group has demonstrated that dimeric Immunoglobulin A can penetrate tumor cells, neutralize oncogenic drivers in endosomes, and expel them from the cytosol. This mechanistic insight suggests that engineered antibodies targeting this pathway may effectively reach previously inaccessible targets. Investigating antibody production within intratumoral germinal centers and understanding the impact of different immunoglobulins on malignant progression could furnish new tools for the therapeutic arsenal, including the development of tumor-penetrating antibodies. This review aims to elucidate the nature of humoral adaptive immune responses in human cancer and explore how they could herald a new era of immunotherapeutic modalities. By expanding the scope of antitumor immunotherapies, these approaches have the potential to benefit a broader range of cancer patients, particularly through the utilization of tumor cell-penetrating antibodies.

Abstract γδ T cells, in contrast to the conventional MHC-restricted αβ, recognize and kill tumor cells in an MHC-unrestricted manner, highlighting their potential for anti-tumor therapies. However, the phenotypes of γδ T cells infiltrating human tumors and their role in anti-tumor immunity remain poorly understood. To assess this, we characterized by Immuno-Seq/iRepertoire the repertoire of γδ-chains used by intra-tumoral γδ T cells in human cancers from FACS-sorted T cells in freshly dissociated high-grade serous ovarian cancers (HGSOCs), non-small cell lung cancer (NSCLC), and small cell lung cancer (SCLC). Our analysis confirmed that δ1 and δ3 TILs are abundant in all diseases. Interestingly, γδ TILs show heterogenous Vγ-chain repertoires, although TCRVγ9 was the dominant γ-chain. We then encapsulated and run 10X (single-cell) analyses, with sorted, bar-coded, δ1 plus δ2 TILs. All tumors showed distinctive clusters of stem-like cells expressing TCF7, IL7R and CD27 (δ1stem); plus effector T cells expressing high levels of granzymes, IFNG and perforin and NK receptors (δ1Eff). Importantly, we found low expression of PD-1, with only a small cluster of δ1 TILs with TOX expression in lung cancer. Therefore, our data indicate that: 1) γδ T cells quasi-universally infiltrate human carcinomas; 2) δ1 T cells outnumber δ2 T cells in tumors; 3) δ1 TILs use a variety of Vγ chains, with dominant Vγ9 and 4) γδ T cell tumor infiltration is associated with better outcome.

Signaling through Notch receptors intrinsically regulates tumor cell development and growth. Here, we studied the role of the Notch ligand Jagged2 on immune evasion in non -small cell lung cancer (NSCLC). Higher expression of JAG2 in NSCLC negatively correlated with survival. In NSCLC pre -clinical models, deletion of Jag2 , but not Jag1 , in cancer cells attenuated tumor growth and activated protective anti -tumor T cell responses. Jag2 - /- lung tumors exhibited higher frequencies of macrophages that expressed immunostimulatory mediators and triggered T cell -dependent anti -tumor immunity. Mechanistically, Jag2 ablation promoted Nr4a-mediated induction of Notch ligands DLL1/4 on cancer cells. DLL1/4-initiated Notch1/2 signaling in macrophages induced the expression of transcription factor IRF4 and macrophage immunostimulatory functionality. IRF4 expression was required for the anti -tumor effects of Jag2 deletion in lung tumors. Antibody targeting of Jagged2 inhibited tumor growth and activated IRF4-driven macrophage -mediated anti -tumor immunity. Thus, Jagged2 orchestrates immunosuppressive systems in NSCLC that can be overcome to incite macrophage -mediated anti -tumor immunity.

Necroptosis can promote antigen-specific immune responses, suggesting induced necroptosis as a therapeutic approach for cancer. Here we sought to determine the mechanism of immune activation but found the necroptosis mediators RIPK3 and MLKL dispensable for tumor growth in genetic and implantable models of breast or lung cancer. Surprisingly, inducing necroptosis within established breast tumors generates a myeloid suppressive microenvironment that inhibits T cell function, promotes tumor growth, and reduces survival. This was dependent upon the release of the nuclear alarmin interleukin-1α (IL-1α) by dying cells. Critically, IL-1α release occurs during chemotherapy and targeting this molecule reduces the immunosuppressive capacity of tumor myeloid cells and promotes CD8+ T cell recruitment and effector function. Neutralizing IL-1α enhances the efficacy of single agent paclitaxel or combination therapy with PD-1 blockade in preclinical models. Low IL1A levels correlates with positive patient outcome in several solid malignancies, particularly in patients treated with chemotherapy.

Immuno-oncology has traditionally focused on conventional MHC-restricted αβ T cells. Yet, unconventional γδ T cells, which kill tumor cells in an MHC-unrestricted manner, display characteristics of effector activity and stemness without exhaustion and are nearly universally observed in human gynecologic malignancies, correlating with improved outcomes. These cells do not have a clear counterpart in mice but are also found in the healthy female reproductive tract. Interventions that modulate their in vivo activity, or cellular therapies utilizing γδ T cells as an allogeneic, “off-the-shelf” platform (e.g., for chimeric antigen receptor expression) hold significant potential against challenging tumors like ovarian cancer, which has been stubbornly resistant to the immune checkpoint inhibitors that change the landscape of other human tumors. Here, we discuss recent discoveries on the specific populations of γδ T cells that infiltrate human gynecologic cancers, their anti-tumor activity, and the prospect of redirecting their effector function against tumor cells to develop a new generation of immunotherapies that extends beyond the traditional αβ T cell-centric view of the field.

Abstract Chimeric Antigen Receptor (CAR) T cell therapy has proven to be successful in treating hematological malignancies. However, its effectiveness against solid tumors has been suboptimal so far, due to the strong immunosuppressive conditions and metabolic restrictions present in the tumor microenvironment. Furthermore, the use of autologous T cells for CAR product manufacturing has several disadvantages. Here, we demonstrate the effectiveness of a new CAR T cell platform using cord blood-derived γδ T cell subsets, which can be used allogeneically (“off-the-shelf”) and recapitulate the populations primarily found in solid tumors. As targeting motifs, we used scFv sequences specifically targeting transmembrane molecules expressed in metastatic SCLC and other tumors, but not in vital tissues, which were identified through a comprehensive proteogenomic approach. To minimize PD-1-driven inhibition and enhance metabolic re-programming, we designed a new CD3z-less CAR architecture, which is more effective than conventional second-generation CARs. Our results demonstrate that γδ T cells are natural killers independent of MHC presentation, superior to αβ T cells, allowing the generation of multiples ‘off-the-shelf’ CAR T cell products. Moreover, the new architecture demonstrated better efficiency in killing tumor cells, thus supporting a rationale for future trials aimed at rendering CAR T cells effective against the most frequent and aggressive human solid tumors.

This file contains the Supplementary legends describing the Supplementary Figures 1-5.

Chimeric antigen receptor (CAR) T cells have been largely unsuccessful in the treatment of non-hematologic malignancies, in part due to immunosuppressive networks at solid tumor beds and a paucity of viable targets. We previously showed that conventional 41BB/CD3ζ-based second-generation CAR T cells targeting OR5V1, an olfactory receptor with negligible expression in vital organs but present in various epithelial tumors, demonstrate therapeutic efficacy in models of gynecologic malignancies. To enhance metabolic superiority and antitumor effectiveness, we sought to generate a novel CD3ζ-less CAR containing the transmembrane and intracellular domains of Natural killer group 2 member D (NKG2D), which is expressed on the surface of natural killer (NK) cells, NKT cells and CD8 cells.

Dimeric IgA (dIgA) can move through cells via the IgA/IgM polymeric immunoglobulin receptor (PIGR), which is expressed mainly on mucosal epithelia. Here, we studied the ability of dIgA to target commonly mutated cytoplasmic oncodrivers. Mutation-specific dIgA, but not IgG, neutralized KRASG12D within ovarian carcinoma cells and expelled this oncodriver from tumor cells. dIgA binding changed endosomal trafficking of KRASG12D from accumulation in recycling endosomes to aggregation in the early/late endosomes through which dIgA transcytoses. dIgA targeting of KRASG12D abrogated tumor cell proliferation in cell culture assays. In vivo, KRASG12D-specific dIgA1 limited the growth of KRASG12D-mutated ovarian and lung carcinomas in a manner dependent on CD8+ T cells. dIgA specific for IDH1R132H reduced colon cancer growth, demonstrating effective targeting of a cytoplasmic oncodriver not associated with surface receptors. dIgA targeting of KRASG12D restricted tumor growth more effectively than small-molecule KRASG12D inhibitors, supporting the potential of this approach for the treatment of human cancers.

The pathogenesis of cutaneous T-cell lymphoma (CTCL) remains unclear. Using single-cell RNA or T-cell receptor (TCR) sequencing of 32 619 CD3+CD4+ and CD26+/CD7+ and 29 932 CD3+CD4+ and CD26-/CD7- lymphocytes from the peripheral blood of 7 patients with CTCL, coupled to single-cell ATAC-sequencing of 26,411 CD3+CD4+ and CD26+/CD7+ and 33 841 CD3+CD4+ and CD26-/CD7- lymphocytes, we show that tumor cells in S e ' zary syndrome and mycosis fungoides (MF) exhibit different phenotypes and trajectories of differentiation. When compared to MF, Se ' zary cells exhibit narrower repertoires of TCRs and exhibit clonal enrichment. Surprisingly, we identified >= 200 mutations in hematopoietic stem cells from multiple patients with S e ' zary syndrome. Mutations in key oncogenes were also present in peripheral S e ' zary cells, which also showed the hallmarks of recent thymic egression. Together our data suggest that CTCL arises from mutated lymphocyte progenitors that acquire TCRs in the thymus, which complete their malignant transformation in the periphery.

Objective. To demonstrate that shared antibody responses in endometriosis and endometriosis-associated ovarian cancer spontaneously antagonize malignant progression and can be leveraged to develop future immu-notherapies.Methods. B cells from cyopreserved clear cell ovarian carcinoma (CCC, n = 2), endometrioid ovarian carci-noma (EC, n = 2), and endometriomas (n = 2) were isolated, activated, and EBV-immortalized. Antibodies were purified from B cell supernatants and used for screening arrays containing most of the human proteome. Targets were prioritized based on accessibility (transmembrane or secreted proteins), expression in endometri-osis and cancer, and concurrent IgA and IgG responses. We focused on antibodies targeting tumor-promoting syndecan binding protein (SDCBP) to demonstrate anti-tumor activity. Immunoblots and qPCR were performed to assess SDCBP expression in ovarian cancer and endometriosis cell lines and tumor samples. Recombinant IgG4 was generated using the variable heavy and light chains of dominant B cell receptors (BCRs) reacting against the extracellular domain of SDCBP, and used in in vivo studies in human CCC-and high-grade serous ovarian carci-noma (HGSOC)-bearing immunodeficient mice. Results. Nine accessible proteins detected by both IgA and IgG were identified in all samples -including SDCBP, which is expressed in ovarian carcinomas of multiple histologies. Administration of alpha-SDCBP IgG4 in OVCAR3 (HGSOC), TOV21G and RMG-I (CCC) tumor-bearing mice significantly decreased tumor volume compared to control irrelevant IgG4.Conclusions. Spontaneous antibody responses exert suboptimal but measurable immune pressure against malignant progression in ovarian carcinomas. Using tumor-derived antibodies for developing novel immuno-therapeutics warrants further investigation.(c) 2023 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Supplementary Figure from Olfactory Receptor OR2H1 Is an Effective Target for CAR T Cells in Human Epithelial Tumors

Radiation therapy (RT) can prime and boost systemic anti-tumor effects via STING activation, resulting in enhanced tumor antigen presentation and antigen recognition by T cells. It is increasingly recognized that optimal anti-tumor immune responses benefit from coordinated cellular (T cell) and humoral (B cell) responses. However, the nature and functional relevance of the RT-induced immune response are controversial, beyond STING signaling, and agonistic interventions are lacking. Here, we show that B and CD4+ T cell accumulation at tumor beds in response to RT precedes the arrival of CD8+ T cells, and both cell types are absolutely required for abrogated tumor growth in non-irradiated tumors. Further, RT induces increased expression of 4-1BB (CD137) in both T and B cells; both in preclinical models and in a cohort of patients with small cell lung cancer treated with thoracic RT. Accordingly, the combination of RT and anti-41BB therapy leads to increased immune cell infiltration in the tumor microenvironment and significant abscopal effects. Thus, 4-1BB therapy enhances radiation-induced tumor-specific immune responses via coordinated B and T cell responses, thereby preventing malignant progression at unirradiated tumor sites. These findings provide a rationale for combining RT and 4-1bb therapy in future clinical trials.

This file contains the Supplementary Figures 1-5. Supplementary Figure 1. Phospho-AMPKα1 levels increase in tumor-MDSC. Supplementary Figure 2. Tumor cell-derived GM-CSF triggers Ampkα expression in MDSC through Stat-5 activation. Supplementary Figure 3. MDSC in human myeloid progenitors treated with GM-CSF plus IL-6 for 7 days. Supplementary Figure 4. Extended survival of Prkaa1-null mice bearing ovarian tumors. Supplementary Figure 5. Effects of Prkaa1KO PMN-MDSC in tumor growth.

Objectives: To develop chimeric antigen receptor (CAR) T cells targeting the olfactory receptor family 5 subfamily V member 1 (OR5V1) for the treatment of ovarian cancer. Methods: OR5V1 expression was quantitated by real-time quantitative polymerase chain reaction (RT-QPCR) and western blot analysis of 17 normal tissues and 75 ovarian cancers of various histologies. The sequence of an antibody fragment that recognizes the extracellular domain of OR5V1 was predicted from the amino acid sequence of OR5V1. Focusing on this antibody fragment, potential linear B cell epitopes were predicted. The peptides were biotinylated and tetramerized using fluorescently labeled streptavidin. Immortalized B cells derived from 10 human high-grade serous ovarian cancers reacting with the tetramer were fluorescence-activated cell sorting (FACS) sorted and subjected to 10x single cell B cell receptor sequencing. The sequences of the variable heavy and variable light chains of a dominant clone representing 54% of the population were identified and used to predict the sequence of a single-chain variable fragment (scFv) interacting with OR5V1. We designed the CAR construct using the olfactory receptor signal peptide, followed by the OR5V1 scFv, linked by a glycine/serine spacer, followed by a CD8a hinge, and transmembrane domains, and intracellular domains of co-stimulatory 4-1BB and CD3ζ. The construct was cloned into a retroviral vector, and human T cells were retrovirally transduced to express the OR5V1 CAR. The OR5V1 -specific cytotoxic killing of HeLa cells with endogenous expression of OR5V1 was demonstrated in vitro using luciferase assays and in vivo using an immunodeficient mouse model. Differences between the means of experimental groups were calculated using a two-tailed unpaired Student’s t-test or two-way ANOVA with multiple comparisons. A p-value of <0.05 was considered statistically significant. Results: OR5V1 is expressed in ovarian cancers of multiple histologies, with expression in normal human tissues limited to the testis. There was no cytotoxic killing by OR5V1 CAR T cells of healthy human adipocytes, hepatocytes, or neurons. OR5V1 CAR T cells demonstrated cytotoxicity against HeLa cells, with nearly 100% specific killing in a dose-dependent manner, compared to mock transduced T cells (p=0.0002). Administration of OR5V1 CAR T cells in HeLa tumor-bearing mice significantly abrogated tumor growth, while mock transduced T cells were unable to prevent accelerated malignant progression (p<0.0001). Tumors treated with OR5V1 CAR T cells demonstrated not only reduced tumor volumes (p<0.0001) and weights (p=0.0023) but also significant central necrosis compared to those treated with mock transduced T cells. Conclusions: This study characterizes the expression pattern of OR5V1 in normal tissues and ovarian tumors of multiple histologies. We also demonstrate the therapeutic efficacy of targeting OR5V1-expressing tumors with CAR T cells re-directed against OR5V1, with a likely admissible toxicity profile. Objectives: To develop chimeric antigen receptor (CAR) T cells targeting the olfactory receptor family 5 subfamily V member 1 (OR5V1) for the treatment of ovarian cancer. Methods: OR5V1 expression was quantitated by real-time quantitative polymerase chain reaction (RT-QPCR) and western blot analysis of 17 normal tissues and 75 ovarian cancers of various histologies. The sequence of an antibody fragment that recognizes the extracellular domain of OR5V1 was predicted from the amino acid sequence of OR5V1. Focusing on this antibody fragment, potential linear B cell epitopes were predicted. The peptides were biotinylated and tetramerized using fluorescently labeled streptavidin. Immortalized B cells derived from 10 human high-grade serous ovarian cancers reacting with the tetramer were fluorescence-activated cell sorting (FACS) sorted and subjected to 10x single cell B cell receptor sequencing. The sequences of the variable heavy and variable light chains of a dominant clone representing 54% of the population were identified and used to predict the sequence of a single-chain variable fragment (scFv) interacting with OR5V1. We designed the CAR construct using the olfactory receptor signal peptide, followed by the OR5V1 scFv, linked by a glycine/serine spacer, followed by a CD8a hinge, and transmembrane domains, and intracellular domains of co-stimulatory 4-1BB and CD3ζ. The construct was cloned into a retroviral vector, and human T cells were retrovirally transduced to express the OR5V1 CAR. The OR5V1 -specific cytotoxic killing of HeLa cells with endogenous expression of OR5V1 was demonstrated in vitro using luciferase assays and in vivo using an immunodeficient mouse model. Differences between the means of experimental groups were calculated using a two-tailed unpaired Student’s t-test or two-way ANOVA with multiple comparisons. A p-value of <0.05 was considered statistically significant. Results: OR5V1 is expressed in ovarian cancers of multiple histologies, with expression in normal human tissues limited to the testis. There was no cytotoxic killing by OR5V1 CAR T cells of healthy human adipocytes, hepatocytes, or neurons. OR5V1 CAR T cells demonstrated cytotoxicity against HeLa cells, with nearly 100% specific killing in a dose-dependent manner, compared to mock transduced T cells (p=0.0002). Administration of OR5V1 CAR T cells in HeLa tumor-bearing mice significantly abrogated tumor growth, while mock transduced T cells were unable to prevent accelerated malignant progression (p<0.0001). Tumors treated with OR5V1 CAR T cells demonstrated not only reduced tumor volumes (p<0.0001) and weights (p=0.0023) but also significant central necrosis compared to those treated with mock transduced T cells. Conclusions: This study characterizes the expression pattern of OR5V1 in normal tissues and ovarian tumors of multiple histologies. We also demonstrate the therapeutic efficacy of targeting OR5V1-expressing tumors with CAR T cells re-directed against OR5V1, with a likely admissible toxicity profile.

Abstract Although chimeric antigen receptor (CAR)-expressing T cells have proven success in hematologic malignancies, their effectiveness in solid tumors has been largely unsuccessful thus far. We found that some olfactory receptors are expressed in a variety of solid tumors of different histologic subtypes, with a limited pattern of expression in normal tissues. Quantification of OR2H1 expression by qRT-PCR and Western blot analysis of 17 normal tissues, 82 ovarian cancers of various histologies, eight non–small cell lung cancers (NSCLCs), and 17 breast cancers demonstrated widespread OR2H1 expression in solid epithelial tumors with expression in normal human tissues limited to the testis. CAR T cells recognizing the extracellular domain of the olfactory receptor OR2H1 were generated with a targeting motif identified through the screening of a phage display library and demonstrated OR2H1-specific cytotoxic killing in vitro and in vivo, using tumor cells with spontaneous expression of variable OR2H1 levels. Importantly, recombinant OR2H1 IgG generated with the VH/VL sequences of the CAR construct specifically detected OR2H1 protein signal in 60 human lung cancers, 40 ovarian carcinomas, and 73 cholangiocarcinomas, at positivity rates comparable with mRNA expression and without OR2H1 staining in 58 normal tissues. CRISPR/Cas9-mediated ablation of OR2H1 confirmed targeting specificity of the CAR and the tumor-promoting role of OR2H1 in glucose metabolism. Therefore, T cells redirected against OR2H1-expressing tumor cells represent a promising therapy against a broad range of epithelial cancers, likely with an admissible toxicity profile.

e14507 Background: We hypothesized that tumor-infiltrating B cells in endometriosis and endometriosis-associated ovarian cancer can be used to identify novel, targetable antigen domains to inhibit the progression of ovarian carcinomas. We aimed to identify targets that are spontaneously recognized by B-cell-derived antibodies within ovarian clear cell carcinoma (CCC), endometrioid carcinoma (EC), and endometriosis and to determine the preclinical anti-cancer efficacy of a candidate antibody that recognizes the extracellular domain of an identified target. Methods: B cells from freshly dissociated CCC (n = 2), EC (n = 2), and endometriomas (n = 2) were isolated, activated, and EBV-immortalized. Antibodies were purified from B cell supernatants and used for screening in a proteome array. Targets were prioritized based on accessibility (transmembrane or secreted proteins), expression in endometriosis and cancer, and concurrent IgA and IgG responses. Tumor-promoting syndecan binding protein (SDCBP) was identified and SDCBP-reactive B cells were FACS-sorted and subjected to single cell B cell receptor sequencing to determine the variable heavy and light chain sequences of enriched clonotypes. We then generated a recombinant IgG4 antibody targeting SDCBP with the dominant VH/VL matching sequences. Immunoblots and qPCR were performed to assess SDCBP expression in ovarian cancer cell lines and tumor samples. In vivo studies compared anti-tumor potential of the α-SDCBP IgG4 with controls using immunodeficient mouse models of human CCC and high-grade serous ovarian carcinoma (HGSOC). Results: Nine accessible proteins were detected by both IgA and IgG in all samples, including SDCBP. SDCBP is expressed in ovarian cancer cell lines and tumor samples of multiple histologies, including CCC, EC, and HGSOC. Administration of α-SDCBP IgG4 in TOV21G (CCC) tumor-bearing mice significantly decreased tumor volume compared to non-antigen-specific irrelevant IgG4 (iIgG4, p = 0.002) and vehicle (0.001), and correspondingly trended toward decreased tumor weight compared to vehicle (p = 0.06). Likewise, administration of α-SDCBP IgG4 in OVCAR3 (HGSOC) tumor-bearing mice significantly decreased tumor volume compared to iIgG4 (p = 0.03) and trended toward decreased tumor weight (p = 0.06). Conclusions: An α-SDCBP IgG4 has demonstrated anti-tumor efficacy in SDCBP+ CCC and HGSOC, and SDCBP-targeted therapy for endometriosis and associated malignant conditions, as well as HGSOC, warrants further investigation.

Despite repeated associations between T cell infiltration and outcome, human ovarian cancer remains poorly responsive to immunotherapy. We report that the hallmarks of tumor recognition in ovarian cancer-infiltrating T cells are primarily restricted to tissue-resident memory (TRM) cells. Single-cell RNA/TCR/ATAC sequencing of 83,454 CD3+CD8+CD103+CD69+ TRM cells and immunohistochemistry of 122 high-grade serous ovarian cancers shows that only progenitor (TCF1low) tissue-resident T cells (TRMstem cells), but not recirculating TCF1+ T cells, predict ovarian cancer outcome. TRMstem cells arise from transitional recirculating T cells, which depends on antigen affinity/persistence, resulting in oligoclonal, trogocytic, effector lymphocytes that eventually become exhausted. Therefore, ovarian cancer is indeed an immunogenic disease, but that depends on ∼13% of CD8+ tumor-infiltrating T cells (∼3% of CD8+ clonotypes), which are primed against high-affinity antigens and maintain waves of effector TRM-like cells. Our results define the signature of relevant tumor-reactive T cells in human ovarian cancer, which could be applicable to other tumors with unideal mutational burden.