Search Results (7,826)

Breast cancer, especially triple-negative breast cancer (TNBC) and endocrine-resistant disease, remains difficult to treat because of limited effective targeted therapies. In this study, we evaluated the antitumor activity and potential mechanism of MHO7, a marine-derived ophiobolin metabolite, in ER-positive ZR-75-30 cells, tamoxifen-resistant LCC2 cells, and TNBC MDA-MB-231 models. MHO7 dose-dependently reduced cell viability, wound closure, and clonogenic growth in ZR-75-30 and LCC2 cells, with IC₅₀ values of 11.53 and 10.43 μM, respectively. MHO7 also promoted apoptotic cell death, accompanied by increased reactive oxygen species accumulation and altered expression of apoptosis-related proteins, including Bcl-2 and caspase-3. N-acetyl-L-cysteine partially attenuated MHO7-induced apoptosis and YAP reduction in MDA-MB-231 cells, suggesting a contribution of oxidative stress. Molecular docking predicted that MHO7 could occupy the conserved TEAD palmitoylation pocket, and subsequent in vitro analyses showed suppression of YAP/TAZ-TEAD signaling, including reduced YAP nuclear accumulation and decreased TEAD4 expression. In an MDA-MB-231 xenograft model, MHO7 significantly inhibited tumor growth, reduced CD31-positive microvessel density, and decreased Hippo pathway-related transcriptional readouts. These findings indicate that MHO7 exerts broad antitumor activity in breast cancer models through oxidative stress-associated apoptosis and modulation of YAP/TAZ-TEAD signaling, supporting its further development as a lead compound for treatment-resistant breast cancer. Full article

Background: Squamous cell carcinomas (SCCs) share squamous differentiation and may engage the programmed cell death protein 1/programmed death-ligand 1 (PD-1/PD-L1) pathway, although their causes, biology, and treatment differ by anatomical site. We evaluated tumor response, short-term survival, and grade 3–4 adverse events after neoadjuvant immune-checkpoint blockade, with or without chemotherapy, followed by surgery. Methods: A comprehensive search of PubMed, Embase, the Cochrane Library, and clinical trial registries was conducted from inception to October 2024. Prospective and retrospective studies evaluating neoadjuvant immunotherapy, with or without chemotherapy, before surgery in patients with SCC were included. In mixed-histology studies, data were eligible only when SCC outcomes could be extracted separately. Pooled proportions and 95% confidence intervals (CIs) were estimated with random-effects models. Results: A total of 44 studies involving 2586 patients with six anatomical SCC groups were included. The pooled objective response rate (ORR) was 0.70 (95% CI, 0.59–0.80), clinical complete response (cCR) rate was 0.17 (95% CI, 0.10–0.28), and pathological complete response (pCR) rate was 0.30 (95% CI, 0.27–0.34). The pooled 1-year progression-free survival (PFS), disease-free survival (DFS), and overall survival (OS) rates were 0.82 (95% CI, 0.79–0.86), 0.86 (95% CI, 0.75–0.92), and 0.92 (95% CI, 0.90–0.93), respectively. The pooled incidence of grade 3–4 adverse events was 0.18 (95% CI, 0.14–0.23). Because the PD-L1 subgroup contained only one study for most outcomes, checkpoint-target subgroup findings were considered exploratory. Conclusions: Existing predominantly single-arm evidence suggests antitumor activity of neoadjuvant immune-checkpoint blockade, with or without chemotherapy, in selected patients with resectable SCC. Because esophageal SCC accounted for most studies and clinical heterogeneity was substantial, these pooled proportions should not be interpreted as comparative effects or as evidence of uniform benefit across SCC sites. Full article

Cancer progression is driven by early dysregulation of the immune system and tumor-intrinsic mechanisms. Hypoxia, lactate accumulation and IL-6 signaling induce highly overlapping tumor-promoting effects, including angiogenesis, epithelial–mesenchymal transition, metastasis, immune evasion and treatment resistance, suggesting that these pathways interact and amplify one another. This parallel activation complicates therapeutic targeting, as inhibition of one pathway may be compensated for by another. Increased proteolytic activity emerges early during tumor development and profoundly alters immune regulation. We recently identified a protease-generated albumin fragment, the IL-6-inducing factor (IL-6IF), which triggers pathological IL-6 production. IL-6 in turn enhances both HIF-1α expression and nuclear translocation, promotes glycolysis and lactate production, and forms positive feedback loops with STAT3 and multiple signaling pathways. Together, these mechanisms integrate into a self-sustaining IL-6/HIF-1α/STAT3 axis that drives tumor progression and suppresses anti-tumor immunity. The strong overlap among IL-6, its enhancing loops and hypoxia-driven mechanisms highlights IL-6 as a central regulator of metabolic and immunological reprogramming in cancer. However, a broad IL-6 blockade can impair physiological immune function. Selective inhibition of IL-6IF offers a novel strategy to prevent pathological IL-6 production while preserving physiological IL-6-dependent immune function required for effective tumor control. Reducing pathologically enhanced IL-6 synthesis by targeting IL-6IF, therefore, might represent a potential therapeutic approach to disrupt multiple tumor-promoting pathways simultaneously and may thereby improve responsiveness to cancer immunotherapy. Full article

Triple-negative breast cancer (TNBC) remains a highly aggressive malignancy with limited therapeutic options and frequent resistance to platinum-based chemotherapy. Rosmarinic acid (RA), a naturally occurring polyphenol, has attracted considerable interest as a potential chemosensitising agent. This study investigated the anticancer activity and the underlying mechanisms of RA combined with cisplatin (CDDP) in 4T1 breast cancer cells while assessing the cytotoxic responses of non-cancerous HaCaT keratinocytes as a preliminary indicator of differential treatment sensitivity. Cytotoxicity was assessed using the MTT assay, followed by calculation of the Combination Index (CI), Drug Reduction Index (DRI), and Selectivity Index (SI). The generation of intracellular reactive oxygen species (ROS) was evaluated by DCFH-DA fluorescence imaging, and the functional contribution of oxidative stress was examined using N-acetyl-L-cysteine (NAC) rescue experiments. Apoptosis was analysed by Annexin V/PI flow cytometry, NucBlue nuclear staining, and Calcein-AM/propidium iodide (PI) Live/Dead fluorescence imaging. Three-dimensional (3D) tumour spheroids were used to assess treatment-induced alterations in spheroid morphology, morphometric parameters, viability based on adenosine triphosphate (ATP), and Live/Dead staining. The expression of genes related to apoptosis was determined by RT-qPCR, and potential molecular mechanisms were explored using the construction of protein–protein interaction (PPI) networks together with Gene Ontology (GO) and Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway enrichment analyses. The combination of RA + CDDP exhibited strong synergistic cytotoxicity in 4T1 cells while demonstrating comparatively lower toxicity toward HaCaT keratinocytes. Combination treatment markedly increased intracellular ROS generation, whereas NAC significantly reduced ROS accumulation and partially restored cell viability, indicating that oxidative stress is a major but not exclusive mediator of cytotoxicity. Combined treatment significantly enhanced apoptotic cell death, increased chromatin condensation and membrane damage, upregulated the expression of Bax, Casp9, Cycs, and Trp53, and downregulated Bcl2, consistent with transcriptional regulation of intrinsic apoptotic signalling. In 3D tumour spheroids, the combination markedly reduced spheroid size, disrupted structural integrity, decreased ATP-based viability, and substantially increased tumour cell death compared to monotherapy. Bioinformatic analyses identified central genes related to apoptosis and cell survival and predicted significant enrichment of PI3K/Akt, p53, MAPK, and apoptosis signalling pathways. RA significantly potentiates the antitumor efficacy of CDDP through synergistic induction of ROS-associated apoptotic signalling while showing a more favourable cytotoxic response in 4T1 breast cancer cells than in non-cancerous HaCaT keratinocytes. The integrated findings from two-dimensional (2D) and 3D models, NAC rescue experiments, molecular analyses, and bioinformatics collectively support the potential of RA as a promising chemosensitising adjuvant for CDDP-based breast cancer therapy and warrant further validation in preclinical in vivo models. Full article

Background: Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal cancers, with a five-year survival rate of less than 12%. Oncolytic viruses are considered a promising immunotherapeutic approach, but their effectiveness is often limited by the innate interferon response, which is the main antiviral barrier in resistant tumors. A combination of an oncolytic virus with JAK/STAT pathway inhibitors has been proposed to overcome this resistance. Methods: In this study, we investigated the oncolytic and immunotherapeutic potential of the attenuated yellow fever vaccine strain YFV 17D in combination with the JAK1/JAK2 inhibitor ruxolitinib in a panel of six PDAC cell lines with diverse genetic profiles and JAK/STAT signaling activities and in a syngeneic immunocompetent PAN02 mouse model. Results: In vitro, we identified three distinct response patterns: synergistic enhancement of viral replication and cytopathic effect, lack of synergism due to absent interferon signaling, and increased viral replication without cytopathic effect. Despite different cell mutation profiles, the cell response patterns were determined by the basal JAK/STAT activity of each cell line rather than by specific KRAS or TP53 mutation. In vivo, the combination therapy significantly extended median survival compared to YFV 17D monotherapy and the control group and induced tumor regression in 62.5% of animals. Since no difference in intratumoral viral RNA was detected between the combination and monotherapy groups, we suggest that the antitumor effect in vivo was mediated not by enhanced viral replication, but by activation of adaptive immunity. This is indirectly suggested by increased intratumoral IL-12, a fourfold increase in CD8⁺ T cell infiltration, a reduction in CD4⁺ cells, and the generation of virus-neutralizing antibodies. No systemic cytokine surge, neurovirulence, or viral dissemination was observed, suggesting the safety of the proposed regimen. Conclusions: These findings clarify the immune mechanisms determining the efficacy of YFV 17D combined with ruxolitinib and establish the basis for personalized patient stratification by tumor interferon signaling status. Full article

Colorectal cancer (CRC) remains one of the leading causes of cancer-related morbidity and mortality worldwide despite substantial advances in surgery, chemotherapy, targeted therapies, and immunotherapy. The limited efficacy of current treatment strategies in advanced disease and the emergence of therapeutic resistance highlight the urgent need for novel adjunctive therapeutic approaches. Increasing evidence indicates that chronic stress and sustained activation of β-adrenergic signaling promote colorectal tumor initiation, progression, angiogenesis, metastatic dissemination, and immune evasion, thereby identifying this pathway as a potential therapeutic target. Drug repurposing has emerged as an attractive strategy for accelerating the development of new anticancer therapies by identifying novel applications for clinically approved drugs with well-established safety profiles. Among these, β-blockers have gained considerable attention because of their ability to inhibit β-adrenergic signaling and modulate multiple oncogenic pathways implicated in CRC progression. Although accumulating preclinical and observational clinical evidence suggests that β-blockers may possess anticancer potential, the underlying molecular mechanisms and their translational relevance have not yet been comprehensively integrated. This review provides a critical overview of the current evidence regarding the therapeutic potential of β-blockers in CRC by integrating findings from preclinical and clinical studies. Particular emphasis is placed on the regulation of key signaling pathways, including cAMP/PKA/CREB, PI3K/AKT/mTOR, and RAS/RAF/MEK/ERK, as well as on the effects of β-blockers on tumor cell proliferation, apoptosis, angiogenesis, epithelial–mesenchymal transition, metastasis, and modulation of the tumor microenvironment and antitumor immune responses. However, significant barriers limit the translation of these findings into routine clinical practice, including the limited representativeness of preclinical models, potential hemodynamic adverse effects, and the inherent limitations of observational studies. Importantly, owing to the lack of prospective randomized clinical trials, the current evidence remains insufficient to establish the clinical efficacy of β-blockers in colorectal cancer. Although β-blockers possess several characteristics that make them attractive candidates for drug repurposing, including a well-established safety profile, widespread availability, and low cost, further mechanistic studies, prospective randomized clinical trials, and biomarker-based patient stratification are essential to determine their clinical efficacy and define their role in personalized CRC therapy. Full article

Glioblastoma multiforme (GBM) remains one of the most aggressive and treatment-resistant brain tumors, characterized by rapid proliferation and poor patient prognosis. Novel therapeutic strategies are urgently needed to improve clinical outcomes. In this study, we investigated the cytotoxic and pro-apoptotic effects of bortezomib (BORT), a proteasome inhibitor, and graphene oxide (GO), a nanomaterial with known anticancer potential, on human glioblastoma cell lines. Treatment with BORT and GO, both individually and in combination, significantly reduced cell viability in a dose-dependent manner, as determined by MTT. In this study, we observed enhanced apoptotic cell death, accompanied by increased activation of both caspase-8 and caspase-9, indicating simultaneous engagement of extrinsic and intrinsic apoptotic pathways. Western blot analysis demonstrated downregulation of anti-apoptotic proteins Bcl-2 and upregulation of pro-apoptotic markers (NOXA, cleaved PARP). A central finding of this work is the pronounced increase in intracellular reactive oxygen species (ROS) levels following BORT–GO treatment. The elevated ROS levels observed in BORT–GO-treated cells compared with free bortezomib therefore suggest that GO-mediated oxidative stress may amplify proteasome inhibition-induced apoptosis, which is particularly visible in the A172 and LN229 cell lines. Notably, the combination of BORT and GO may suggest a potential cooperative mechanism through proteasome inhibition and oxidative stress induction. These findings indicate that graphene oxide may modulate the antitumor efficacy of bortezomib in a cell line-dependent manner and support further investigation of this combination as a promising therapeutic approach for glioblastoma. Full article

Acute myeloid leukemia (AML) is a heterogeneous hematologic malignancy characterized by the clonal expansion of myeloid blasts and the persistence of leukemic stem cells (LSCs) within a profoundly remodeled bone marrow (BM) microenvironment. Despite advances in molecular stratification and the introduction of targeted agents, long-term outcomes remain unsatisfactory, particularly in older and high-risk patients. Increasing evidence indicates that leukemogenesis and treatment resistance are critically sustained by a permissive immune milieu, in which LSCs, myeloid-derived suppressor cells, leukemia-associated macrophages, and dysfunctional T and NK cells shape an immunosuppressive “leukemic niche.” This evolving understanding has renewed interest in immune-based strategies capable of restoring effective antitumor immunity. Bispecific antibodies (bsAbs) are engineered molecules designed to engage AML-associated antigens while simultaneously recruiting and activating immune effector cells, most commonly T cells or NK cells. By promoting immune synapse formation independently of major histocompatibility complex expression and conventional co-stimulatory pathways, bsAbs can overcome several mechanisms of immune escape. In this review, we summarize the biological rationale for immunotherapy in AML, with a focus on the role of the BM microenvironment and immune dysregulation. We then discuss the structural and functional properties of IgG-like and non-IgG-like bsAbs, key antigenic targets such as CD33, CD123, CD70 and others, and the main T-cell- and NK-cell-engaging platforms under clinical investigation. Finally, we highlight emerging clinical data, principal toxicities, and the challenges of integrating bsAbs into existing treatment algorithms, including combinations with hypomethylating agents, BCL-2 inhibitors, and allogeneic stem cell transplantation. A deeper understanding of AML immune biology and antigen expression patterns will be essential to optimize bsAb design, maximize therapeutic benefit, and minimize on-target off-tumor toxicity. Full article

Breast cancer remains a major global health burden. Dactylospongia species have been explored for their cytotoxic potential. This study aims to evaluate the cytotoxic potential of compounds derived from the marine sponge Dactylospongia elegans. Dactylospongia elegans were collected from the Lembeh Strait, macerated using methanol, then partitioned to an ethyl acetate fraction. The cytotoxic activity of these fractions was assessed using MDA-MB-231 cells while toxicity testing was done using the BSLT. TLC was carried out to determine the groups of compounds, while LC-MS/MS was used to predict active compounds contained in the ethyl acetate fractions. In silico studies were conducted as preliminary studies to determine the antitumor mechanism. The ethyl acetate fraction and F4 subfraction of Dactylospongia elegans exhibited cytotoxicity toward MDA-MB-231 cells with IC₅₀ values of 15.72 and 41.76 µg/mL, respectively. The BSLT indicated the strongest toxicity belongs to the F6 subfraction (LC₅₀ = 32.831 µg/mL). TLC analysis confirmed the presence of major secondary metabolites as terpenoids, steroids, and alkaloids, then confirmed with LC-MS/MS including 5-epi-illimaquinone and calciferol. Molecular docking revealed that calciferol exhibited the strongest binding affinity toward tyrosine kinase and p53–MDM2 receptors, with binding energies of −10.13 and −10.28 kcal/mol, respectively. These findings suggest that Dactylospongia elegans contains bioactive constituents with potential anticancer activity, particularly against TNBC. Full article

Background: IL-15 is a promising cytokine for cancer immunotherapy. IL-15 promotes differentiation and homeostasis of innate and adaptive immune cells, and their cytolytic effector functions. The IL-15 receptor is composed of IL-15Rα, IL-15Rβ and the common γ_c chains. IL-15 is also trans-presented as IL-15Rα:IL-15 complex to IL-15Rβ:γ_c on neighboring cells. IL-15Rα is dispensable for early immune response to infections and in autoimmune diabetes. The role of IL-15Rα in antitumor immune responses remains unclear. Methods: In WT, Il15^−/− and Il15ra^−/− mice, we studied the growth of syngeneic tumor cell lines and tumor immune surveillance against endogenous fibrosarcoma induced by methylcholanthrene (MCA). Immune gene signature and total proteome analysis were performed on MCA-induced tumors. Results: Lack of IL-15 or IL-15Rα did not enhance the growth of implanted tumor cell lines, despite reduced immune cell infiltration. MCA-induced tumor incidence was reduced in mice lacking IL-15Rα but not IL-15, although both are required for efficient tumor immunoediting. Il15^−/− and Il15ra^−/− tumors showed reduced Ifng expression but displayed differential modulation of Ifng-responsive genes. Proteome profiles of Il15^−/− tumors, but not tumor-derived cell lines, showed significant reduction in antigen presentation pathways. B16-F10 melanoma cells expressing NLRC5, the IFNγ-induced transcriptional activator of tumor antigen presentation, still required IL-15 but not IL-15Rα for efficient tumor control. Conclusions: Our findings show that IL-15 plays a negligible role in immunosurveillance against spontaneous tumor development, whereas IL-15Rα restrains immunosurveillance. Neither IL-15 nor IL-15Rα have a significant impact on implanted tumor models, although IL-15 facilitates efficient control of highly immunogenic tumors for which IL-15Rα is dispensable. Full article

Sea cucumber cooking liquid contains water-soluble macromolecules, but its bioactive polysaccharide fractions remain insufficiently characterized. In this study, a polysaccharide-rich fraction, P0.7, was isolated from sea cucumber cooking liquid and evaluated for its antitumor activity against HCT-15 colorectal cancer. P0.7 was characterized as a relatively homogeneous sulfated acidic heteropolysaccharide-rich fraction containing 83.61 ± 3.65% total sugar, 13.67 ± 2.48% sulfate, 9.98 ± 1.22% uronic acid, and 5.11 ± 0.34% protein. It was mainly composed of galactose, mannose, and glucose, accounting for 34.12%, 26.93%, and 17.99%, respectively. Among the tested tumor cell lines, HCT-15 cells showed the highest sensitivity to P0.7, with inhibition rates of approximately 45% and 63% at 100 and 200 μg/mL, respectively. P0.7 promoted apoptosis, induced G2/M-phase accumulation, increased ROS production, disrupted mitochondrial membrane potential, regulated Bax, Bcl-2, and cleaved caspase-3 expression, and enhanced γ-H2AX-related DNA damage-response signaling in HCT-15 cells. In an HCT-15 xenograft mouse model, P0.7 reduced terminal tumor volume and tumor weight without causing obvious body weight loss. Histological and immunohistochemical analyses further showed reduced Ki67 staining, increased TUNEL-positive signals, and enhanced γ-H2AX staining in tumor tissues. These findings indicate that P0.7 suppresses HCT-15 colorectal cancer growth in vitro and in vivo, possibly through mechanisms associated with ROS accumulation, mitochondrial apoptosis, and γ-H2AX-related DNA damage response. These findings provide additional experimental evidence supporting the investigation of sea cucumber-derived polysaccharides for potential pharmaceutical applications. Full article

Gymnaconitum gymnandrum, a Tibetan medicinal herb, is distributed across high-altitude regions of China. Despite its high toxicity, it exhibits analgesic, anti-inflammatory, antitumor, and other pharmacological activities. It is used topically for skin conditions and orally for rheumatism. Its main bioactive components are alkaloids. A new organic amine alkaloid has been isolated from the plant and structurally identified using HRMS, NMR, and X-ray diffraction. Full article

Oxidative stress in the tumor microenvironment, which is its own intrinsic property, is frequently utilized to deal with the drug-targeting issue in the nanoparticle drug delivery system. For this purpose, reactive oxygen species (ROS)-sensitive nanoparticles encapsulating doxorubicin (DOX) and chlorin e6 (Ce6) were synthesized for treatment of MDA-MB-231 breast cancer cells. Hyaluronic acid (HA) with a reductive end was conjugated with methoxy poly(ethylene glycol) (PEG) using thioketal diamine (ThdNH₂) linkage (HA-b-PEG copolymer). Then, Ce6 were conjugated to the carboxylic acid group of HA via ThdNH₂ (HA(Ce6)-b-PEG copolymer). DOX was physically incorporated to make DOX-incorporated HA(Ce6)-b-PEG copolymer nanoparticles (DOX-NP). HA(Ce6)-b-PEG copolymer nanoparticles (empty NP) and DOX-NP have a tiny particle size, less than 200 nm, with spherical morphology. They were responsively disintegrated according to the hydrogen peroxide (H₂O₂) concentration, then the release rate of Ce6 or DOX was accelerated, indicating that empty NP and DOX-NP have ROS sensitivity. DOX-resistant MDA-MB-231 cells were prepared by continuous treatment of DOX for three months. DOX-NP were efficiently internalized into the cells while intra-cellular delivery of DOX itself was inhibited. DOX-NP has higher anticancer activity against DOX-resistant MDA-MB-231 cells than that of DOX itself since cells were resistant to DOX itself. Under light irradiation, DOX-NP significantly decreased the viability of DOX-resistant MDA-MB-231 cells while DOX itself did not properly affect cell viability. Empty NP also efficiently inhibited cell viability rather than that of Ce6 itself while both of them did not affect the cell viability in the absence of light irradiation. Furthermore, empty NP showed higher ROS generation than that of Ce6 itself. DOX-NP more efficiently induced apoptosis/necrosis than DOX itself. In DOX-resistant MDA-MB-231 cell-bearing mice, DOX-NP was efficiently delivered to tumor tissue. DOX-NP greatly inhibited the growth of tumors under light irradiation, more than that of DOX itself or empty NP. In conclusion, DOX-NP showed promising antitumor activity against DOX-resistant MDA-MB-231 cells. Full article

CBL-B is an intracellular E3 ubiquitin ligase that acts as a T cell checkpoint by raising activation thresholds and limiting effector function. Here, genetic targeting of CBL-B enhances the performance of adoptively transferred T cells and CAR T cells under tumor microenvironment-like stress. In fully immunocompetent mouse models, Cblb deficiency or transient Cblb silencing improves control of MC-38 colon carcinoma and autochthonous mammary tumors, demonstrating that CBL-B restrains anti-tumor immunity. Cblb-deficient T cells show enhanced expansion and effector/effector-memory differentiation during an in vivo mixed lymphocyte reaction, confirming a cell-intrinsic brake function of CBL-B during sustained antigenic challenge. In a syngeneic Panc02-EpCAM model, Cblb-deficient anti-EpCAM CAR T cells show superior tumor control, enhanced infiltration, prolonged survival, and preserved effector function despite chronic antigen exposure and TGF-β. Mechanistically, Cblb targeting maintains granzyme B and IFN-γ production and is associated in vitro with increased GSDME-linked pyroptotic tumor cell death, consistent with features of immunogenic cell death. These findings extend previous CBL-B CAR T work from lymphocyte-deficient to immunocompetent settings and support CBL-B inhibition as a strategy to engineer CAR T cells that resist suppressive tumor microenvironments while promoting a more inflammatory mode of tumor killing. Full article

Breast cancer is the most common cancer in women, causing more than 600,000 deaths every year. The human microbiome is increasingly recognized as a key regulator of cancer initiation, progression, and therapeutic response. Postbiotics—defined as non-viable microbial cells and/or their structural components and metabolites that confer health benefits—are emerging as promising and safer alternatives to live probiotics in oncology. This review provides a comprehensive mechanistic overview of the potential role of postbiotics against cancer, with a specific focus on breast cancer. Preclinical evidence demonstrates that selected postbiotics exert dose- and time-dependent anticancer effects against multiple breast cancer subtypes by modulating key oncogenic pathways (such as PI3K/AKT and NF-κB) and inducing epigenetic regulation through histone deacetylase inhibition. Beyond direct effects on tumor cell proliferation and apoptosis, postbiotics influence the breast cancer microenvironment by reshaping cytokine networks, suppressing pro-metastatic inflammation, and enhancing antitumor immune responses through the activation of NK cells and T cells. We also provide emerging links between microbiome composition, estrobolome activity, and breast cancer subtype-specific biology. Despite these encouraging findings, the clinical translation of postbiotics in oncology remains limited. Currently, only one registered clinical trial investigates postbiotics in the oncology setting (melanoma), and no clinical trials have specifically evaluated postbiotics in breast cancer patients. This highlights a substantial translational gap between preclinical evidence and clinical application. Accordingly, well-designed, tumor-specific clinical trials are urgently needed to validate the safety, efficacy, and therapeutic potential of postbiotics as novel strategies in personalized breast cancer management. Full article