Postbiotics, considered the functional successors of live probiotics, retain most of probiotics’ structural and/or bioactive properties, and are key mediators of probiotic–environment interactions. Beyond influencing tumor proliferation, metastasis, and immune regulation, postbiotics can enhance the effectiveness of current anti-cancer treatments. Postbiotic-based cancer therapy represents an advanced evolution of bacterial treatment with improved safety and treatment potential. However, the field is limited by postbiotics’ imprecise definition and lack of standardized manufacturing methods, which together hinder their clinical application. Here, we establish a systematic classification of postbiotics based on their formation processes, focusing on the complex mechanisms underlying their activity in anti-tumor therapy, their therapeutic promise, and their current clinical use and challenges. Our aim is to guide future research, translation, and industrial development.

Tumor theranostics, which integrates accurate diagnosis and precise therapy, has emerged as a pivotal approach in modern oncology for improving treatment efficacy and reducing off-target toxicity. Click chemistry, which is characterized by high efficiency, selectivity, biocompatibility, and modularity, has become an indispensable tool for constructing versatile theranostic systems. This review systematically summarizes the recent progress in click chemistry-based tumor theranostic systems, starting with an overview of core click reactions and the unique features in biomedical applications. We then focus on the application of click chemistry within a diagnosis-therapy-theranostics framework to three key aspects of tumor theranostics: (i) tumor diagnosis (molecular imaging probes and circulating tumor cell detection); (ii) tumor therapy (chemotherapy, phototherapy, immunotherapy, and gene therapy); and (iii) integrated theranostics (multimodal imaging-guided combinatorial therapy). Furthermore, the current challenges, such as the biocompatibility of catalysts and in vivo reaction efficiency, are critically discussed. Finally, we highlight promising directions, including stimuli-responsive click reactions, AI-assisted probe design, and personalized theranostic systems. This review not only serves as a comprehensive reference for researchers but also highlights how click chemistry uniquely bridges molecular design with clinical functionality, distinguishing click chemistry from conventional conjugation or labeling methods by enabling spatiotemporal control, modular integration, and bioorthogonal precision in complex biological settings.

Biomineralization is a highly regulated, multi-scale biological process that is well-characterized in physiologic contexts but remains poorly understood in pathologic settings. Tumor-associated calcification frequently occurs in clinical practice but is often regarded as an imaging feature rather than an active biological phenomenon. Existing evidence has indicated that tumor calcification is closely linked to cancer progression, prognosis, and underlying biological behavior. This review synthesizes current knowledge on tumor-associated biomineralization from a multidisciplinary perspective, integrating insights from oncology, cell biology, pathology, materials science, and systems biology. The major types and microstructural features of calcium deposition that occur in tumors are summarized and the clinical correlations are discussed. The proposed molecular and cellular mechanisms, including organelle-mediated mineral nucleation, metabolic regulation, differentiation-driven processes, and cell fate-dependent pathways, were further examined. Advances in multi-omics technologies, biomimetic models, and analytical characterization methods are highlighted as critical enablers for mechanistic investigation across biological scales. Finally, emerging strategies that exploit induced tumor calcification using engineered materials as a potential drug free therapeutic and diagnostic approach are discussed. By framing tumor calcification as an active, regulated phenotype, this review aims to provide a unified conceptual framework, identify current knowledge gaps, and encourage future research toward translational applications in cancer diagnosis and treatment.

New therapies and supportive care have converted several cancer types into chronic conditions. Yet, some tumors exhibit features reproducibly correlated with poor prognosis outcome (PPO-tumors). Bacteria in a tumor environment can inactivate chemotherapeutics and are a feature of PPO-tumors, although standard diagnostic tests for tumor infections do not exist. Optimism is high for nanotechnologic innovations but nanoparticulate chemotherapeutics based on enhanced permeability and retention in a human tumor environment have only shown limited treatment benefits. Moreover, treatment of infected tumors in animals with stimuli-responsive nanocarriers loaded with an antibiotic/chemotherapeutic combination has demonstrated limited benefits compared to treatment with combinations of carrier-free antibiotics and chemotherapeutics. Development of nanoparticulate chemotherapeutics with significant benefits in human clinical use is estimated to take several decades, which is too long for patients with PPO-tumors. Herein we hypothesize the following: 1-all diagnosed PPO-tumors are infected with bacteria; 2-all PPO-tumors in mice and humans exhibit enhanced permeability to chemotherapeutics; and 3-all diagnosed PPO-tumors must be treated from the onset with a combination of carrier-free antibiotics and chemotherapeutics. Each hypothesis was critically evaluated and judged plausible and clinically acceptable. Potential clinical treatment of PPO-tumors, presuming bacterial infection without diagnosis, with an approved antibiotic and chemotherapeutic free drug combination requires a paradigm change in treatment concept towards more lenient antibiotic use. However, many cancer patients already require antibiotics during chemotherapeutic treatment and combined carrier-free antibiotic/chemotherapeutic treatment may provide an immediate pathway to re-sensitize PPO-tumors to clinically used chemotherapeutics and alter the prognosis to a more favourable outcome.

Cancer immunotherapy has revolutionized oncology by harnessing the immune system to eliminate malignant cells, yet its efficacy remains constrained by insufficient antigen presentation, limited T cell infiltration, and the immunosuppressive tumor microenvironment (TME). Nanotechnology provides strategies to address these barriers by enabling the precise delivery of antigens, adjuvants, cytokines, checkpoint inhibitors, and nucleic acids, while protecting labile cargos and allowing for controlled release. Beyond serving as carriers, nanoparticles can regulate antitumor immunity by enhancing antigen presentation, promoting T cell priming and infiltration, and remodeling the TME. This review outlines key physiological barriers to in vivo nanoparticle delivery and the corresponding engineering optimization strategies, and systematically summarizes representative advances in using nanomaterials to enhance antigen presentation, promote T cell priming and intratumoral infiltration, and remodel the tumor microenvironment. We further discuss major translational limitations, including heterogeneous tumor accumulation, intracellular trafficking bottlenecks, safety considerations, and manufacturing consistency, and finally highlight the realizable potential of nano-immunotherapy to improve both the efficacy and specificity of cancer immunotherapy.