Therapeutic Target In Cancer Research Articles

Functional roles of microRnas in vasculogenic mimicry and resistance to therapy in human cancers: an update.

Vasculogenic mimicry (VM) alludes to the ability of cancer cells to organize on three-dimensional channels-like structures to obtain nutrients and oxygen. This mechanism confers an aggressive phenotype, metastatic potential, and resistance to chemotherapy resulting in a poor prognosis. Recent studies have been focused on the identification of microRNAs (miRNAs) that regulate the VM representing potential therapeutic targets in cancer. A overview of the roles of miRNAs on VM development, and their functional relationships with tumor microenvironment. The functions of cancer stem-like cells in VM, and resistance to therapy are also discussed. Moreover, the modulation of VM by natural compounds is explored. The clinical significance of deregulated miRNAs as potential therapeutic targets in tumors showing VM is further highlighted. The miRNAs are regulators of protein-encoding genes involved in VM; however, their specific expression signatures with clinical value in large cohorts of patients have not been established yet. We considered that genomic profiling of miRNAs could be useful to define some hallmarks of tumors such as stemness, drug resistance and VM in cancer patients. However, additional studies are needed to establish the relevant role of miRNAs as effective therapeutic targets in tumors that have developed VM.

Protease-activated receptor 2: a promising therapeutic target for women's cancers

Protease-activated receptor 2: a promising therapeutic target for women's cancers

Unmasking the NLRP3 inflammasome in dendritic cells as a potential therapeutic target for autoimmunity, cancer, and infectious conditions.

Proper and functional immune response requires a complex interaction between innate and adaptive immune cells, which dendritic cells (DCs) are the primary actors in this coordination as professional antigen-presenting cells. DCs are armed with numerous pattern recognition receptors (PRRs) such as nucleotide-binding and oligomerization domain-like receptors (NLRs) like NLRP3, which influence the development of their activation state upon sensation of ligands. NLRP3 is a crucial component of the immune system for protection against tumors and infectious agents, because its activation leads to the assembly of inflammasomes that cause the formation of active caspase-1 and stimulate the maturation and release of proinflammatory cytokines. But, when NLRP3 becomes overactivated, it plays a pathogenic role in the progression of several autoimmune disorders. So, NLRP3 activation is strictly regulated by diverse signaling pathways that are mentioned in detail in this review. Furthermore, the role of NLRP3 in all of the diverse immune cells' subsets is briefly mentioned in this study because NLRP3 plays a pivotal role in modulating other immune cells which are accompanied by DCs' responses and subsequently influence differentiation of T cells to diverse T helper subsets and even impact on cytotoxic CD8+ T cells' responses. This review sheds light on the functional and therapeutic role of NLRP3 in DCs and its contribution to the occurrence and progression of autoimmune disorders, prevention of diverse tumors' development, and recognition and annihilation of various infectious agents. Furthermore, we highlight NLRP3 targeting potential for improving DC-based immunotherapeutic approaches, to be used for the benefit of patients suffering from these disorders.

NB compounds are potent and efficacious FOXM1 inhibitors in high-grade serous ovarian cancer cells

BackgroundGenetic studies implicate the oncogenic transcription factor Forkhead Box M1 (FOXM1) as a potential therapeutic target in high-grade serous ovarian cancer (HGSOC). We evaluated the activity of different FOXM1 inhibitors in HGSOC cell models.ResultsWe treated HGSOC and fallopian tube epithelial (FTE) cells with a panel of previously reported FOXM1 inhibitors. Based on drug potency, efficacy, and selectivity, determined through cell viability assays, we focused on two compounds, NB-73 and NB-115 (NB compounds), for further investigation. NB compounds potently and selectively inhibited FOXM1 with lesser effects on other FOX family members. NB compounds decreased FOXM1 expression via targeting the FOXM1 protein by promoting its proteasome-mediated degradation, and effectively suppressed FOXM1 gene targets at both the protein and mRNA level. At the cellular level, NB compounds promoted apoptotic cell death. Importantly, while inhibition of apoptosis using a pan-caspase inhibitor rescued HGSOC cells from NB compound-induced cell death, it did not rescue FOXM1 protein degradation, supporting that FOXM1 protein loss from NB compound treatment is specific and not a general consequence of cytotoxicity. Drug washout studies indicated that FOXM1 reduction was retained for at least 72 h post-treatment, suggesting that NB compounds exhibit long-lasting effects in HGSOC cells. NB compounds effectively suppressed both two-dimensional and three-dimensional HGSOC cell colony formation at sub-micromolar concentrations. Finally, NB compounds exhibited synergistic activity with carboplatin in HGSOC cells.ConclusionsNB compounds are potent, selective, and efficacious inhibitors of FOXM1 in HGSOC cells and are worthy of further investigation as HGSOC therapeutics.

Genetically Engineered CLDN18.2 CAR-T Cells Expressing Synthetic PD1/CD28 Fusion Receptors Produced Using a Lentiviral Vector.

This study aimed to develop synthetic Claudin18.2 (CLDN18.2) chimeric antigen receptor (CAR)-T (CAR-T) cells as a treatment for advanced gastric cancer using lentiviral vector genetic engineering technology that targets the CLDN18.2 antigen and simultaneously overcomes the immunosuppressive environment caused by programmed cell death protein 1 (PD-1). Synthetic CAR T cells are a promising approach in cancer immunotherapy but face many challenges in solid tumors. One of the major problems is immunosuppression caused by PD-1. CLDN18.2, a gastric-specific membrane protein, is considered a potential therapeutic target for gastric and other cancers. In our study, CLDN18.2 CAR was a second-generation CAR with inducible T-cell costimulatory (CD278), and CLDN18.2-PD1/CD28 CAR was a third-generation CAR, wherein the synthetic PD1/CD28 chimeric-switch receptor (CSR) was added to the second-generation CAR. In vitro, we detected the secretion levels of different cytokines and the killing ability of CAR-T cells. We found that the secretion of cytokines such as interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) secreted by three types of CAR-T cells was increased, and the killing ability against CLDN18.2-positive GC cells was enhanced. In vivo, we established a xenograft GC model and observed the antitumor effects and off-target toxicity of CAR-T cells. These results support that synthetic anti-CLDN18.2 CAR-T cells have antitumor effect and anti-CLDN18.2-PD1/CD28 CAR could provide a promising design strategy to improve the efficacy of CAR-T cells in advanced gastric cancer.

Abstract PO3-25-08: Artificial Intelligence-based screening of small molecule inhibitors of phosphoenolpyruvate carboxykinase 2 (PCK2), a novel cancer therapeutic target

Abstract Background: Metabolic rewiring is a hallmark of cancer that is often mediated by alterations in metabolic isozyme expression. Isozymes that are overexpressed in cancer and catalyze rate limiting steps in key metabolic processes are potential therapeutic targets. We previously identified phosphoenolpyruvate carboxykinase 2 (PCK2) as cancer dominant isoform, required for maintaining high metabolic activity and proliferation of lung, prostate, and breast cancer (BC) cells in vitro and in vivo. No PCK2 specific small molecule inhibitors exist. Methods: mRNA expression levels were assessed in the TCGA data. PCK2 MISSION shRNAs (Millipore) were used to knock-down expression of PCK2 in BC cells. Alterations in metabolic flux caused by PCK2 down-regulation were examined via 13C-labeling and mass spectrometry using a SCIEX 5500 QTRAP and SelexION instrument for mobility separation of metabolites. The AtomNetTM (Atomwise Inc.) deep convolutional neural network structure-based drug design software was used to identify candidate small molecule PCK2 inhibitors which were tested in PCK1 and PCK2 in vitro enzyme activity assays. The lead compound was assessed for drug-like properties by QickPropV4.0.001w, and its growth inhibitory activity was tested in MDA-MB-321 and BT-549 cells. Results: Analysis of mRNA levels in TNBC samples revealed a significant decrease in PCK1 expression compared to normal tissues, while PCK2 expression remained elevated or even increased. Quantification of mRNA levels in TNBC cell lines confirmed the higher expression of PCK2 compared to PCK1. To assess functional significance of PCK2 expression, we downregulated PCK2 using shRNA constructs in TNBC cell lines. Western blot analysis confirmed efficient knockdown of PCK2 protein without affecting PCK1 expression. Clonogenic assays demonstrated that PCK2-depleted BT-549 and MDA-MB-231 cells exhibited impaired proliferation, with reduced colony number and size compared to control cells. Metabolic analysis of PCK2-depleted TNBC cells demonstrated decreased levels of glycolytic and TCA intermediates and reduced flux through pyruvate carboxylase, indicating altered metabolic pathways upon PCK2 depletion. To identify potential inhibitors of PCK2, virtual screening was conducted using compound structures. We used a PCK2 protein structure homology model and designated the 3-mercaptopicolinic acid-binding site of the PCK1 structure as the site of interest to perform virtual drug screening of 7 million diverse compounds. The first screen yielded 86 structures to be tested in vitro, of which 5 demonstrated > 16% PCK2 inhibition. The top hit (IC50=2.4µM) was used to refine a second round of in silico screen that yielded 87 second-round candidates that were assessed for PCK2 inhibition in vitro. 3-(3,4-dihydroxyphenyl)-2-hydroxypropanoate emerged as the lead compound. QickProp predicted favorable absorption, distribution, metabolism, and excretion properties, but relatively low cell permeability (apparent Caco-2 and MDCK2 cell permeabilities 18 nm/sec and 8 nm/sec, respectively). The specificity of 3-(3,4-dihydroxyphenyl)-2-hydroxypropanoate was tested in PCK1 and PCK2 enzymatic assays and revealed IC50 of 500nM on PCK1 and an IC50 of 3 nM on PCK2. We next tested the cell growth inhibitory effect of 3-(3,4-dihydroxyphenyl)-2-hydroxypropanoate on parental MDA-MB-231 and BT-549 cells and their PCK2 knockdown clones. Cell growth and viability significantly decreased in the MDA-MD-231 and BT-549 parental cells (the IC50 for MDA-MB-231 was 173 μM) and in shRNA non-targeting control cells, but not in the PCK2 depleted clones, demonstrating PCK2-dependent inhibitory effect. Conclusion: We identified 3-(3,4-dihydroxyphenyl)-2-hydroxypropanoate as a high affinity selective PCK2 enzyme inhibitor. This compound also has significant growth inhibitory activity in BC cell lines in vitro and represents a novel therapeutic lead compound. Citation Format: Alejandro Rios Hoyo, Naing Lin Shan, Hao-Kuen Lin, Gerson Espinoza Campos, Mostafa Ahmed, Sheila Umlauf, Rebecca Cardone, Yulia V. Surovtseva, Vignesh Gunasekharan, Lajos pusztai. Artificial Intelligence-based screening of small molecule inhibitors of phosphoenolpyruvate carboxykinase 2 (PCK2), a novel cancer therapeutic target [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 PO3-25-08.

An overview on liposarcoma subtypes: Genetic alterations and recent advances in therapeutic strategies.

Liposarcoma (LPS) is a rare malignancy of adipocytic differentiation. According to World Health Organization classification, LPS comprises of four principle subtypes Atypical lipomatous tumor/Well-differentiated liposarcoma (ATL/WDLPS), Dedifferentiated liposarcoma (WDLPS), Myxoid liposarcoma (MLPS), and Pleomorphic liposarcoma (PLPS). Each subtype can develop at any location and shows distinct clinical behavior and treatment sensitivity. ATL/ WDLPS subtype has a higher incidence rate, low recurrence, and is insensitive to radiation and chemotherapy. DDLPS is the focal progression of WDLPS, which is aggressive and highly metastasizing. MLPS is sensitive to radiation and chemotherapy, with a higher recurrence rate and metastasis. PLPS subtype is highly metastasizing, has a poor prognosis, and exhibiting higher recurrence rate. Initial histological analysis provides information for the characterization of LPS subtypes', further molecular and genetic analysis provides certain subtype specifications, such as gene amplifications and gene fusions. Such molecular genetic alterations will be useful as therapeutic targets in various cancers, including the LPS subtypes. A wide range of novel therapeutic agents based on genetic alterations that aim to target LPS subtypes specifically are under investigation. This review summarizes the LPS subtype classification, their molecular genetic characteristics, and the implications of genetic alterations in therapeutics.

Abstract PO2-24-04: Exploring the role and therapeutic potential of Ubiquitin Specific Peptidase 11 (USP11) in estrogen receptor positive breast cancer

Abstract Dysregulated estrogen receptor (ER) function is a key feature of 70% of breast cancers. In this setting ER primarily functions as a growth-controlling transcription factor driving pro-tumorigenic properties, thus there is a need to identify novel modulators of ER transcriptional activity as alternative therapeutic options. Previously, we showed a significant association between high ubiquitin specific protease 11 (USP11) expression and poor survival in ER+ breast cancer patients, but not in ER- patients, indicating a role for USP11 in ER+ subtypes. However, the precise role of USP11 in controlling ER function remains undescribed. To interrogate USP11 function in ER+ breast cancer we generated a CRISPR USP11 knockout MCF7 breast cancer cell line. Our results showed for the first time that USP11 knockout significantly reduces proliferation, induces G2 cell cycle arrest and apoptosis, abrogates ERα transcriptional activity, significantly impairs cell migration and invasion, whilst also impairing MCF7 cancer stem-cell like properties and malignant transformation in vitro. In addition, we also observed significant dysregulation of epithelial-mesenchymal transition-related markers including E-cadherin, N-cadherin, Snail and Slug. Using RNA-seq of MCF7 cells +/- estradiol, +/- stable USP11 knockdown we identified dysregulated pathways in protein binding, cell adhesion molecule binding and cell cycle regulation following USP11 modulation. Of note, gene expression analysis indicated NCOA3 as the most differentially expressed coding gene. Further validation confirmed a significant reduction in NCOA3- encoded Steroid receptor coactivator- 3 (SRC-3) protein expression following USP11 modulation with immunocytochemical analysis also indicating co-localisation within the nucleus. Frequently upregulated in breast cancer and associated with poor outcome, SRC-3 promotes ER transcriptional activity and co-activates a wide range of additional pro-tumorigenic transcription factors. Thus, SRC-3 modulation offers an attractive therapeutic target in breast cancer. This finding may present a novel role for USP11 in controlling SRC-3 and therefore associated ER transcriptional activity. We then aimed to explore the therapeutic potential of USP11. Although rare in primary breast cancer, activating mutations in the ER ligand-binding domain have recently been linked to recurrent, anti-endocrine resistant disease and metastasis. As such cancers remain dependent on ER-signalling for proliferation, but are resistant to ER targeted therapies, we identified USP11 as a potential novel therapeutic target. Using CRISPR knock-in ER mutant MCF7 cell lines expressing the four most common ER activating mutations, we demonstrated that USP11 knockdown continues to significantly reduce proliferation and abrogates mutant ERα transcriptional activity. We then explored amphipathic cell penetrating peptide RALA encapsulation as a delivery method for siRNA targeting USP11. Optimisation of nanoparticle delivery in the Y537S ER-mutant MCF7 breast cancer cell line achieved significant knockdown of USP11 and ER- related target genes including TFF1, PgR, GREB1 and PKIB in 2D with minimal associated cellular toxicity. To overcome the siRNA-related issues of rapid clearance upon systemic delivery, we then explored the use of a freeze-dried collagen-based scaffold model as an in vitro 3D RALA-encapsulated siRNA delivery system. Here we observed successful delivery of nanoparticle to MCF7 breast cancer cells, with a significant reduction in USP11 mRNA expression. Bio-compatible scaffold- facilitated delivery may therefore offer a more feasible translation of this siRNA-based therapeutic. Overall, this study highlights a novel role for USP11 in various oncogenic pathways. USP11 may therefore offer a novel therapeutic target to be exploited for the management of ER-positive breast cancer, including ER mutant breast cancer. Citation Format: Rachel Moore, Anna Blümel, Elspeth Ward, Elizabeth Sainsbury, Emer Conroy, Fergal O’Brien, Caroline Curtin, Simak Ali, Helen McCarthy, William Gallagher, Darran O'Connor. Exploring the role and therapeutic potential of Ubiquitin Specific Peptidase 11 (USP11) in estrogen receptor positive breast cancer [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 PO2-24-04.

Abstract PO1-25-03: Programmed Death-Ligand 1 and Receptor Tyrosine Kinases in Breast Cancer

Abstract Programmed death-ligand 1 (PD-L1) is an immune checkpoint expressed in a wide range of malignancies leading to immune tolerance and cancer cell immune evasion. Receptor tyrosine kinases (RTKs) are key regulators of cancer cell proliferation, survival, and invasion. The Hepatocyte Growth Factor (HGF) receptor, MET, and the Epidermal Growth Factor Receptor (EGFR) are RTKs known for their tumorigenic potential in a variety of human malignancies. This study aimed to evaluate the effect of the small-molecule tyrosine kinase inhibitors (TKIs) on the expression of PD-L1 in breast cancer cells and the effect of their combination with inflammatory cytokines. The study also assessed the association of the expression of the tumoral PD-L1 mRNA with each of MET and EGFR mRNA expression and the tumor features and treatment outcomes in breast cancer patients using the METABRIC dataset publicly available from cBioPortal for Cancer Genomics. The TKIs crizotinib [a MET inhibitor] and gefitinib [an EGFR inhibitor] were used as a single treatment and in combination with the cytokines; tumor necrosis factor-α (TNF-α) or interferon-γ (INF-γ) in MCF7 and MDA-MB-231 breast cancer cells in vitro. The cells were also treated with the mitogens HGF and EGF. The viability of cells after the different treatments was determined using the MTT viability assay. The effects of the combination treatments were analyzed using combination index (CI) analysis. The expression level of PD-L1 in cancer cells was assessed using Western blotting. The combination treatment of crizotinib with TNF-α and INF-γ produced a synergistic growth inhibition of MCF7 and MDA-MB-231 cells with CI values of 0.31 and 0.55, respectively. Alternatively, combined crizotinib and TNF-α produced an antagonist effect on the viability of MCF7 cells (CI=2.49). The combination of gefitinib with TNF-α produced a synergistic growth inhibition in both MCF7 and MDA-MB-231 cells with CI values of 0.39 and 0.78, respectively. Alternatively, gefitinib resulted in an additive effect when combined with INF-γ (CI=0.99) and an antagonistic effect when combined with TNF-α (CI=2.68) in MCF7 and MDA-MB-231 cells, respectively. Treatment with HGF (50 and 100 ng/ml) increased the protein levels of PD-L1 while EGF (50 and 100 ng/ml) reduced its levels in MDA-MB-231 cells. Treatment with the TKIs crizotinib (0.1-4 µM) and gefitinib (1-40 µM) significantly reduced PD-L1 levels in MDA-MB-231 cells compared to vehicle-treated cells. The analysis of the METABRIC dataset revealed that the mRNA expression of PD-L1 was positively correlated with the mRNA expression of the EGFR gene (r= 0.081, p< 0.001) but not the MET gene. A double-high PD-L1/MET expression was significantly associated with younger age at diagnosis, high-grade carcinoma, greater tumor size, hormone receptor-negative status, HER2-positivity, and non-luminal disease compared to patients with a double-low PD-L1/MET expression. Similar findings were reported for patients with a double-high PD-L1/EGFR expression compared to patients with a double-low PD-L1/EGFR expression. Nevertheless, the mRNA expression of the PD-L1, MET, and EGFR genes as well as the co-expression of PD-L1/MET or PD-L1/EGFR genes did not affect the overall survival of breast cancer patients. Collectively, MET and EGFR TKIs could modulate the effects of inflammatory cytokines differently based on the type of cytokine and the molecular subtype of breast cancer cells. The expression of PD-L1 in breast cancer cells was upregulated by HGF while TKIs reduced its expression. The co-expression of the PD-L1 gene with MET and EGFR genes in breast cancer was associated with advanced disease presentation and worse prognosticators in patients. Together, TKIs that target MET or EGFR could be an appealing therapeutic target in breast cancer, particularly in younger patients with the non-luminal disease. Citation Format: Nehad Ayoub, Muhsen Al-Diabat, Moath Al-Shorman, Laith Al-Eitan. Programmed Death-Ligand 1 and Receptor Tyrosine Kinases in Breast Cancer [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 PO1-25-03.

Abstract PO3-25-01: CTLA4 expression profiles and their association with clinical outcomes of breast cancer

Abstract The cytotoxic T-lymphocyte-associated protein 4 (CTLA4) is involved in the progression of various cancers, but its biological roles in breast cancer (BRCA) remain unclear. Therefore, we performed a systematic multiomic analysis to expound on the prognostic value and underlying mechanism of CTLA4 in BRCA. First, the expression of CTLA4 in pan-cancer was evaluated using the platforms of Oncomine. Afterward, the web-based bioinformatics platforms of GEPIA and UCLAN were used to compare the expression of CTLA4 in breast cancer and normal tissues. Next, we assessed the relationship between CTLA4 mRNA expression and prognosis in breast cancer patients using the PrognoScan Database, Kaplan-Meier Plotter, and R2: Kaplan-Meier Scanner. Additionally, the correlation between CTLA4 expression and immune cell infiltration in breast cancer and functional enrichment analysis of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways was performed to elucidate the potential biological functions of CTLA4. Finally, we used the STRINGdb and cytoHubba plugin Cytoscape to create a PPI network and identify known and predicted structural essentials for CTLA4 functions and the top five hub genes. CTLA4 was highly expressed in BRCA tumor tissue compared to normal tissue (p< 0.01). The CTLA4 mRNA levels in BRCA based on breast cancer subtypes of luminal, Human epidermal growth factor receptor 2 (HER-2), and Triple-negative breast cancer (TNBC) were considerably higher than in normal tissues (p< 0.001). However, the overexpression of CTLA4 was associated with a better prognosis in BRCA (P< 0.001), and was correlated with clinicopathological characteristics including age, T-stage, estrogen receptors (ER), progesterone receptors (PR), and PAM50 (P< 0.01). The infiltration of multiple immune cells was associated with increased CTLA4 expression in BRCA (P< 0.001). CTLA4 was highly enriched in antigen binding, immunoglobulin complexes, lymphocyte-mediated immunity, and cytokine-cytokine receptor interaction. This study provides suggestive evidence of the prognostic role of CTLA4 in breast cancer, which may be a therapeutic target for breast cancer. Furthermore, CTLA4 may influence breast cancer prognosis through antigen binding, immunoglobulin complexes, lymphocyte-mediated immunity, and cytokine-cytokine receptor interaction. These findings help us understand how CTLA4 plays a role in breast cancer and set the stage for more research. Citation Format: Woo Chul Noh, Young Bum Yoo, Kyoung Sik Park, Sang Eun Nam, Seung Hwan Lim. CTLA4 expression profiles and their association with clinical outcomes of breast cancer [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 PO3-25-01.

Abstract PO3-24-07: The role of Hepatitis A Virus Cellular Receptor 1 (HAVCR1) in breast cancer and the impact on penetration of blood brain barrier

Abstract Background: Hepatitis A Virus Cellular Receptor 1 (HAVCR1) is associated with the biological behaviour of several cancers, and has been shown to regulate junctional complexes. However, its role in breast cancer remains unexplored. This study aimed to investigate the effects of HAVCR1 on human breast cancer. Methods: We explored the UALCAN web portal, which is linked to the TCGA database, to determine the expression of HAVCR1 in breast cancer and the Kaplan-Meier plotter to evaluate the correlation with the survival of the patients. HAVCR1 siRNA was used to knock down the HAVCR1 expression in MCF-7 and MDA-MB-231 cell lines. In vitro cell growth, wounding healing, and electric cell impedance sensing (ECIS for assessing cellular proliferation, migration and adhesion) assays were used. Transepithelial resistance (TEER) and paracellular permeability (PCP) were assessed to determine changes in the barrier function of human breast cancer cells. The expression of HAVCR1 and prospective interactive binding molecules of HAVCR1 protein was assessed using quantitative polymerase chain reaction (qPCR). Cellular response to docetaxel was evaluated and shown (IC50). The invasiveness of breast cancer cells through the human cerebral microvessel endothelial cells (hCMEC/D3) cell layers was measured using an in vitro transwell cell invasion assay. Results: HAVCR1 gene expression levels were significantly lower (P< 0.001) in breast cancer tissue compared with normal tissues. Patients with high expression of HAVCR1 had a significantly better relapse-free survival than low expression (P< 0.001). There was no significant difference in overall survival (OS) between the HAVCR1 high and the low expression groups (P=0.22). However, in subgroup analysis, high HAVCR1 expression was associated with better OS in luminal A (P=0.04). Knockdown (KD) HAVCR1 in breast cancer cells influence cell function by enhanced adhesion, proliferation, and migration compared to wild type (WT) cell lines. It was noted that loss of HAVCR1 rendered both MCF-7 and MDA-MB-231 cells resistant to docetaxel (IC50 for WT and HAVCR1 KD respectively being 0.86nM vs 1.75nM for MCF-7 and 1.35nM vs 15.48nM for MDA-MB-231). HAVCR1 KD increase adhesion to hCMEC/D3 cells (53.14±8.23 vs ±99.37±8.97 for MCF-7, P< 0.001; 109.5±97.56 vs 147.1±96.63 for MDA-MB-231, P=0.228, WT and HAVCR1 KD). In the cerebral endothelial cell invasion assay, we found that HAVCR1 KD resulted in a significantly increased invasion of the breast cancer cells through the endothelium (19.27±8.74 vs 33.58±16.81 for MDA-MB-231, P=0.0114, WT and HAVCR1 KD). For the barrier function, the knockdown led to a decrease in TEER and an increase in PCP when compared with WT cells in both cell lines. HAVCR1 KD cells showed decreased barrier function, together with reduced expression of Claudin-1/8/10, occludin, MarvelD3, Tricellulin and ZO1. Conclusions: HAVCR1 is a potential biomarker for breast cancer prognosis. HAVCR1 influences the integrity of barrier function by influence the gene expression of tight junction in breast cancer, and influence the penetration to blood brain barrier. Together, it suggests that HAVCR1 may be a potential therapeutic target in breast cancer. Citation Format: Xiaoshan Cao, Binbin Cong, Wen Jiang, Tracey Martin. The role of Hepatitis A Virus Cellular Receptor 1 (HAVCR1) in breast cancer and the impact on penetration of blood brain barrier [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 PO3-24-07.

Abstract PO2-18-06: Targeting fibroblast growth factor receptor (FGFR1) expression through G-quadruplex stabilization inhibits metastatic breast cancer

Abstract Metastatic breast cancer (MBC) is the most advanced stage of breast cancer. Our understanding of the molecular mechanisms which drive MBC remain incomplete. Epithelial to mesenchymal transition (EMT) and mesenchymal to epithelial transition (MET) promote drug resistance and metastasis. It has been reported that fibroblast growth factor receptor 1 (FGFR1) plays a key role during the EMT:MET cycle. Furthermore, FGFR1 is amplified in 13% of primary and 20% of metastatic breast cancer patients. Therefore, optimizing inhibition of FGFR1 is crucial for the therapeutic targeting of the late stage breast cancer. First, we examined the efficacies of FGFR kinase inhibitors in the murine based dormant 4T07 tumor model. Inhibition of FGFR kinase activity leads to tumor growth inhibition but fail to eradicate dormant breast cancer cells. Therefore, we explored broader approaches to inhibit FGFR1 expression in addition to blockade of its kinase activity. G-quadruplex (G4) structures are secondary DNA structures commonly found upstream of transcriptional start sites (TSS) of oncogenes restricting their expression. Consequently, pharmacological stabilization of G4 structures within the promoters of cancer-related genes via use of small molecules has emerged as a promising therapeutic approach in cancer. Results herein demonstrate that the proximal promoter of FGFR1 contains sequences that form G4. Circular dichroism was used to verify formation of G4 in the FGFR1 proximal promoter. Importantly, use of the G4-binding compound CX-5461 stabilized the FGFR1 G4 structure, blocked the transcriptional activity of the FGFR1 proximal promoter and decreased FGFR1 expression. Therefore, we implemented the G4 stabilizers in FGFR1 expressing and metastatic drug-resistant BC cell lines. This approach results in dramatic downregulation of FGFR1 at the protein level after treatment with the G4 stabilizer. G4 stabilizing agents also interfere with ectopic FGFR1 expression and EMT-driven FGFR1 expression. Importantly, use of the G4-targeting compound CX5461 effectively blocked FGFR1 expression and inhibited FGFR1 downstream signaling, resulting in eradication of dormant breast cancer cells. Finally, in vivo application of CX5461 reduced FGFR1 expression, blocked pulmonary tumor formation and prolonged animal survival. In conclusion, consistent with the clinical observations our evaluation of FGFR kinase inhibitors validates the resistance to FGFR kinase inhibitors in MBC. Our findings indicate that targeting FGFR1 expression through G4 stabilization may be a potential strategy for MBC. Citation Format: Muhammad Safdar, Hang Lin, Sarah Dagher, Jonathan Dickerhoff, Mitchell Ayers, Luis Solorio, Danzhou Yang, Michael Wendt, Saeed Akhand. Targeting fibroblast growth factor receptor (FGFR1) expression through G-quadruplex stabilization inhibits metastatic breast cancer [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 PO2-18-06.

Abstract PO2-24-10: Anti-Tumorigenic Immuno-Microenvironment by AB-329, a Potent and Selective AXL inhibitor, combined with paclitaxel in Triple-Negative Breast Cancer Preclinical Model

Abstract BACKGROUND The Gas6/AXL signaling pathway plays a substantial role in cancer cell survival, proliferation, immunosuppression, and metastasis. Elevated AXL expression is associated with advanced cancer stages and decreased overall survival rates, underscoring its potential as a therapeutic target for metastatic cancers. We investigated this possibility by utilizing AB-329, a selective small molecule AXL kinase inhibitor, to treat triple-negative breast cancer (TNBC). TNBC, typified by the lack of ER, PR, and HER2 expression, frequently displays mesenchymal characteristics and carries a significant risk of metastasis and an immunosuppressive tumor microenvironment. METHODS We assessed AXL protein expression in 28 human and 11 mouse breast cancer cell lines using Western blotting. The Microarray database was utilized to examine AXL gene expression in 40 human breast cancer cells. The Sulforhodamine B proliferation and soft agar assays measured the antiproliferative effect of AB-329 in TNBC cell lines. The in vitro anti-metastatic impact of AB-329 was evaluated through migration and invasion assays. We appraised the anti-tumor effects of AB-329 in combination with paclitaxel using 4T1 and E0771-LMB mouse TNBC xenograft models. We used FACS and CIBERSORTx to perform immune cell type profiling in E0771-LMB xenograft tumor tissues. To understand AB-329’s immunomodulatory effects in tumors, single-cell RNA sequencing was conducted in a humanized mouse model with SUM149 human TNBC xenografts. RESULTS Microarray data revealed higher AXL expression in TNBC cells compared to non-TNBC cells. Western blotting supported this, showing higher AXL protein expression, particularly in basal and mesenchymal subtypes of TNBC cells, compared to luminal breast cancer cells. AB-329 presented moderate antiproliferative effects as a monotherapy in the TNBC cell lines tested, with half-maximal inhibitory concentrations exceeding 5 µM. Nevertheless, combining AB-329 with paclitaxel resulted in significant growth inhibition in all tested TNBC cell lines (p < 0.05). Importantly, AB-329 alone could inhibit TNBC migration and invasion at a concentration of 1 µM (p < 0.01) and showed enhanced inhibition rates when paired with paclitaxel (p < 0.05). The combination of AB-329 and paclitaxel considerably reduced tumor growth in the 4T1 and E0771-LMB xenograft models compared to paclitaxel or AB-329. Total RNA sequencing and CIBERSORTx analysis indicated that the AB-329 and paclitaxel combination increased Natural Killer (NK) cells’ infiltration into E0771-LMB mouse TNBC xenograft tumors compared to single agent-treated tumors. A nearly 2.5-fold increase in NKT cell infiltration was also detected with AB-329 treatment compared to Control in SUM149 human TNBC xenografts. CONCLUSIONS Our preclinical data suggest that AB-329, an AXL inhibitor, could synergize effectively with paclitaxel in TNBC treatment, notably inhibiting tumor cell proliferation and migration while enhancing NK cell infiltration. Intriguingly, we observed an increased infiltration of NKT cells into tumors following AB-329 treatment, which may promote an anti-tumorigenic immuno-microenvironment. These results underscore the necessity for further investigation into the role of AB-329 in modulating the tumor immuno-microenvironment through AXL pathway inhibition and accentuate the potential for combining AB-329 with immunotherapy. Citation Format: Dileep Reddy Rampa, Jon Fuson, Huey Liu, Max Pan, Naoto Ueno, Jangsoon Lee. Anti-Tumorigenic Immuno-Microenvironment by AB-329, a Potent and Selective AXL inhibitor, combined with paclitaxel in Triple-Negative Breast Cancer Preclinical Model [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 PO2-24-10.

Abstract PO1-24-06: Prolactin Hormone-Induced Mammary Differentiation and Anti-tumorigenic Role in Breast Cancer

Abstract The premise of differentiation therapy in cancer is a strategy that aims at engaging-forward differentiation and cellular reprograming restricting the proliferative, tumor repopulation, stemness, EMT and metastatic capacities of tumor cells leading to the cessation of the aggressive tumor phenotype and offering the cancer patients improved survival for decades. Therefore, deciphering molecular mechanisms deriving differentiation in normal mammary and breast cancer cells may allow the discovery of innovative differentiation-based biomarkers and therapeutics in breast cancer. Lactation is an intricate process that results in the ability of the breast cells to produce a complex nutritious biological fluid to nurse the new-born. While the beneficial effects of breastfeeding to the infant is irrefutable, its effects on maternal health are less investigated especially in relation to breast cancer that still affects 1 in 8 women in high income countries and 1 in 20 globally. Importantly, epidemiological studies have linked breastfeeding to reduced risk of breast cancer by promoting terminal differentiation of the breast epithelial cells. While breastfeeding process is regulated by multiple hormones, growth factors, and transcriptional regulators, the lactation hormone prolactin (PRL) is known to be directly implicated in the hormonal control of breastfeeding. Extensive research including our own work has shown that PRL/PRL receptor (PRLR) pathway derives mammary gland development and importantly mammary epithelial cell terminal differentiation allowing successful lactation. In contrast the role of PRL in breast cancer is still to be fully defined. Importantly, we have accumulated compelling evidence using in-silico publicly available patient data sets and molecular data implicating this pathway as a clinically relevant pro-differentiation pathway driving differentiation and cellular reprograming suppressing stemness, EMT, metastasis and tumorigenesis in breast cancer. To better characterize PRL signaling mediating its pro-differentiation effects, we used large-scale unbiased proteomics analysis of PRLR/interacting proteins in breast cancer cells. Our analyses revealed several novel PRLR-interactors. We have further confirmed these interactions through co-immunoprecipitations/western blotting analyses in breast cancer cells representative the different breast cancer subtypes. We also examined their functional contributions to mammary differentiation and tumorigenesis using in vitro and in vivo assays. Moreover, we defined their potential clinical relevance using bioinformatics in silico databases of breast cancer. Together our study delineates novel PRL/PRLR-downstream signaling mediators important for mammary differentiation and tumorigenesis and may thus be useful as biomarkers and/or therapeutic targets in breast cancer. Citation Format: Dana Hamam, Suhad Ali. Prolactin Hormone-Induced Mammary Differentiation and Anti-tumorigenic Role in Breast Cancer [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 PO1-24-06.

Abstract PS16-04: Denosumab as an enhancer of the immune infiltrate in hormone receptor-positive early breast cancer. Subgroup analysis from the D-Biomark window-of-opportunity clinical trial (NCT03691311)

Abstract Background: The receptor activator of nuclear factor κB (RANK) signaling pathway has emerged as a therapeutic target in breast cancer (BC). Recent studies indicate that inhibition of the RANK pathway induces tumor cell differentiation and may enhance the anti-tumor immune response. The D-Biomark clinical trial aims to evaluate the antitumor (antiproliferative and proapoptotic) and immunomodulatory effects of denosumab in HER2-negative early BC. Methods: Patients with early HER2-negative BC scheduled for primary surgery were randomized in a 2:1 ratio to receive two doses of 120 mg denosumab on days 1 and 8 vs no treatment before surgery. Immunohistochemistry (IHC) was used to assess Ki67 (proliferation), cleaved caspase-3 (cell survival), RANK and RANKL. Stromal tumor infiltrating lymphocytes (TILs) and serum markers including free RANKL (sRANKL), tartrate-resistant acid phosphatase 5b (TRACP5b), and osteoprotegerin (OPG) were also analyzed. Paired t-test was used to compare values between core biopsy (biopsy A) and surgical samples (biopsy B). Subgroup analysis by intrinsic subtype was performed on 47 matched cases using PAM50. Results: Between July 2019 and May 2021, we enrolled 60 patients, 58 evaluable, including 10 triple-negative breast cancer (TNBC). The clinicopathologic characteristics of the population at the time of enrollment were well balanced, but the TNBC recruited included 5 out of 10 tumors with a more indolent behavior than the typical tumors of this lineage (apocrine tumors, low cell proliferation). Due to this and the small number of cases, no conclusions can be drawn in this subgroup. RANK expression was detected in 19 tumor cases, while 17 cases expressed RANKL. The treated group showed a decrease in sRANKL (p < 0.000), indicating denosumab activity, while the control group showed no change (p1.0). OPG levels in the experimental group showed a non-significant increase (p0.07), while TRACP5b remained unchanged. Both groups showed a non-clinically relevant increase in cell proliferation (5 percentage points), control p0.04, experimental p0.01. Subgroup analysis of tumors with RANK+ or RANKL+ tumor cells also showed no reduction in Ki67. Cell survival did not decrease in the overall cohort (control p0.05, experimental p0.24), nor in subgroups or in tumors with RANK+ or RANKL+ tumor cells. Denosumab treatment increased TILs in the overall population (control p0.06, experimental p0.0006) and in the subgroups: RANK+ tumors, RANKL+ tumors, premenopausal and postmenopausal, less so in the TNBC group. The subgroup analysis is shown in Table 1. Analysis by intrinsic subtype showed that in the experimental group there was an increase in cases with a change to luminal A lineage (17%) compared to the control group (6%), suggesting a possible cellular differentiation towards less aggressive tumors. Although the number of patients is small, these changes warrant further investigation and highlight the role of denosumab as an immune activator in these luminal tumors known for their low inflammatory infiltrate. Conclusion: Two doses of denosumab prior to surgery did not reduce proliferation or increase apoptosis. However, this short course of denosumab increased TILs in early BC, particularly in luminal tumors, and may induce tumor cell differentiation into luminal A-like tumors. Table. Citation Format: Andrea Vethencourt, Eva Trinidad, Eduard Dorca, Anna Petit, Teresa Soler-Monsó, Agostina Stradella, Cristina Capo, Ander Urriticoechea, Marta Matas, Gema Pérez-Chacon, María Jimenez, Marina Ciscar, Emilia Brizzi, Gonzalo Soria Alcaide, Gonzalo Gomez, Elena Piñeiro, Elvira Purqueras, Amparo Garcia, Ariadna Iserte, M Jesus Pla, Miriam Campos, Miguel Gil-Gil, Sonia Pernas, Eva Gonzalez-Suarez, Catalina Falo. Denosumab as an enhancer of the immune infiltrate in hormone receptor-positive early breast cancer. Subgroup analysis from the D-Biomark window-of-opportunity clinical trial (NCT03691311) [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 PS16-04.

Abstract PO3-26-09: A novel class of RNR inhibitors that induces genomic instability and breast cancer cell death without inducing overt toxicities

Abstract Despite the development of screening techniques and therapies, nearly 30% of breast cancers progress to Stage IV metastatic disease. These advanced cancers are highly proliferative, engaging in ongoing DNA synthesis that requires ribonucleotide reductase (RNR), the rate-limiting enzyme for dNTP synthesis. RRM2, the small subunit of RNR, activates the enzyme, increases deoxynucleotide pools, and is overexpressed in many cancers, including breast cancer. Thus, RNR is an established therapeutic target in advanced breast cancer. Currently, gemcitabine is the only FDA-approved RNR inhibitor used to treat Stage IV disease. As a nucleoside analog, gemcitabine also causes severe dose-limiting toxicities (i.e. myelosuppression and hepatotoxicity) due to off-target DNA replication termination. We hypothesize that a novel, non-nucleoside, RNR inhibitor may overcome these limitations. To address this, we developed TMU27a, a derivative of naphthyl salicylic acyl hydrazone (NSAH), which was identified in an in silico screen for its high-affinity binding to the RNR catalytic site. To measure direct interactions between TMU27a and purified RNR protein, we used surface plasmon resonance, revealing on-target, tight binding (Kd = 150 nM). Unbiased docking and molecular dynamics simulations (using lowest energy calculations) predicted the binding sight of TMU27a to be the catalytic site of RNR, where it is stabilized through extensive interactions formed with conserved residues. Preliminary docking predictions also indicate multiple clash sites between TMU27a and the DNA polymerase lambda nucleotide pocket even in the lowest energy pose (unlike gemcitabine), suggesting that TMU27a inhibits RNR activity through a novel mechanism without significant off-target binding to other nucleotide binding proteins that contribute to toxicity. Demonstrating on-target inhibition, TMU27a reduces dATP levels and induces S and G2/M-phase stalling, leading to significant DNA damage and chromosomal instability. This excessive genomic damage causes growth repression, apoptosis, and senescence in several triple negative breast cancer (TNBC) cell lines. In xenograft mouse models of TNBC, TMU27a fully suppressed tumor growth without impacting mouse weight, suggesting strong drug efficacy in the absence of overt toxicity. Moreover, while short-term exposure to gemcitabine suppresses red and white blood cell populations, TMU27a does not. Together, these data indicate that TMU27a and its potential analogs are novel, non-toxic RNR inhibitors that overcome the limitations of gemcitabine for treating breast cancer. We are currently investigating how and where TMU27a binds human RNR using cryo-electron microscopy with the goal of generating a novel class of RNR inhibitors through structure-based drug design, improving binding affinity and selectivity. Citation Format: Taylor Baker, Kristen Weber-Bonk, Wei Huang, Derek Taylor, Ruth Keri. A novel class of RNR inhibitors that induces genomic instability and breast cancer cell death without inducing overt toxicities [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 PO3-26-09.

LncRNA PCED1B-AS1 mediates miR-3681-3p/MAP2K7 axis to promote metastasis, invasion and EMT in gastric cancer

BackgroundLncRNA PCED1B-AS1 is abnormally expressed in multiple cancers and has been confirmed as an oncogene. Our study aimed to investigate the regulatory mechanism of lncRNA PCED1B-AS1 in gastric cancer.MethodsTCGA database was used to analyze the abnormal expression of lncRNA PCED1B-AS1 in gastric cancer. By database prediction and mass spectrometric analysis, miR-3681-3p and MAP2K7 are potential downstream target molecules of lncRNA PCED1B-AS1 and verified by dual-luciferase report assay. RT-qPCR analysis and western blot were performed to detect the expressions of PCED1B-AS1 and MAP2K7 in gastric cancer cell lines and tissues. CCK-8 kit was applied to measure the cell viability. Wound healing and Transwell experiment were used to detect the migration and invasion. Western blot and immunohistochemical staining were performed to detect the expressions of EMT-related proteins in tissues. The changes of tumor proliferation were detected by xenograft experiment in nude mice.ResultsPCED1B-AS1 expression was higher but miR-3681-3 expression was lower in gastric cancer cell lines or tissues, compared to normal group. Function analysis verified PCED1B-AS1 promoted cell proliferation and inhibited cell apoptosis in gastric cancer cells in vitro and in vivo. LncRNA PCED1B-AS1 could bind directly to miR-3681-3p, and MAP2K7 was found to be a downstream target of miR-3681-3p. MiR-3681-3p mimics or si-MAP2K7 could partly reverse the effect of PCED1B-AS1 on gastric cancer cells.ConclusionPCED1B-AS1 accelerated cell proliferation and inhibited cell apoptosis through sponging miR-3681-3p to upregulate MAP2K7 expression in gastric cancer, which indicated PCED1B-AS1/miR-3681-3p/MAP2K7 axis may serve as a potential therapeutic target for gastric cancer.

Current Perspectives of Matrix Metalloproteinase 11 (MMP11) as a Diagnostic and Therapeutic Target for Cancer

Abstract: Matrix metalloproteinase 11 (MMP11), also known as stromelysin-3, is a member of the matrix metalloproteinases family of proteins that are involved in physiological and pathological extracellular matrix remodelling. MMP11 does not hydrolyse classical MMP substrates, such as laminin and fibronectin, and many of its substrates remain unknown, piquing the interest of researchers. Several studies have reported the role of MMP11 in inducing tumour growth by inhibiting apoptosis and promoting cancer cell migration and invasion. Various reports have shown its potential as a diagnostic and prognostic marker in a majority of cancers. MMP11 also induces an immune response as a tumour-associated antigen, and recent evidence shows the involvement of many microRNAs in targeting MMP11 in cancer, with prospective future applications in cancer immunotherapy and gene silencing. Owing to the importance of MMP11 in both cancer diagnosis and therapy, there is a need for deeper understanding of its mechanism and role in tumour progression. The current review focuses on the role of MMP11 in cell signalling pathways, its expression status in various cancers, and its potential in cancer treatment.

Predictability of B cell clonal persistence and immunosurveillance in breast cancer

B cells and T cells are important components of the adaptive immune system and mediate anticancer immunity. The T cell landscape in cancer is well characterized, but the contribution of B cells to anticancer immunosurveillance is less well explored. Here we show an integrative analysis of the B cell and T cell receptor repertoire from individuals with metastatic breast cancer and individuals with early breast cancer during neoadjuvant therapy. Using immune receptor, RNA and whole-exome sequencing, we show that both B cell and T cell responses seem to coevolve with the metastatic cancer genomes and mirror tumor mutational and neoantigen architecture. B cell clones associated with metastatic immunosurveillance and temporal persistence were more expanded and distinct from site-specific clones. B cell clonal immunosurveillance and temporal persistence are predictable from the clonal structure, with higher-centrality B cell antigen receptors more likely to be detected across multiple metastases or across time. This predictability was generalizable across other immune-mediated disorders. This work lays a foundation for prioritizing antibody sequences for therapeutic targeting in cancer.

Serine Protease 27, a Prognostic Biomarker in Pan-cancer and Associated with the Aggressive Progression of Breast Cancer.

To create effective medicines, researchers must first identify the common or unique genes that drive oncogenic processes in human cancers. Serine protease 27 (PRSS27) has been recently defined as a possible driver gene in esophageal squamous cell carcinoma. However, no thorough pan-cancer study has been performed to date, including breast cancer. Using the TCGA (The Cancer Genome Atlas), the GEO (Gene Expression Omnibus) dataset, and multiple bioinformatic tools, we investigated the function of PRSS27 in 33 tumor types. In addition, prognosis analysis of PRSS27 in breast cancer was carried out, as well as in vitro experiments to verify its role as an oncogene. We first explored the expression of PRSS27 in over 10 tumors and then we looked into PRSS27 genomic mutations. We discovered that PRSS27 has prognostic significance in breast cancer and other cancers' survival, and we developed a breast cancer prognostic prediction model by combining a defined set of clinical factors. Besides, we confirmed PRSS27 as an oncogene in breast cancer using some primary in vitro experiments. Our pan-cancer survey has comprehensively reviewed the oncogenic function of PRSS27 in various human malignancies, suggesting that it may be a promising prognostic biomarker and tumor therapeutic target in breast cancer.