Tumor-Educated Platelet RNA and Circulating Free RNA: Emerging Liquid Biopsy Markers for Different Tumor Types

The incidence and mortality from malignant tumors continue to rise each year. Consequently, early diagnosis and intervention are vital for improving patient' prognosis and survival. The traditional pathological tissue biopsy is currently considered the gold standard for cancer diagnosis. However, it suffers from several limitations including invasiveness, sometimes not repeatable or unsuitable, and the inability to capture the dynamic nature of tumors in terms of space and time. Consequently, these limit the application of tissue biopsies for the diagnosis of early-stage tumors and have redirected the research focus towards liquid biopsies. Blood-based liquid biopsies have thus emerged as a promising option for non-invasive assessment of tumor-specific biomarkers. These minimally invasive, easily accessible, and reproducible tests offer several advantages, such as being mostly complication-free and efficient at monitoring tumor progression and tracing drug resistance. Liquid biopsies show great potential for cancer prediction, diagnosis, and prognostic assessment. Circulating tumor-educated platelets (TEPs) possess the unique ability to absorb nucleic acids from the bloodstream and to modify transcripts derived from megakaryocytes in response to external signals. In addition, circulating free RNA (cfRNA) constitutes a significant portion of the biomolecules present in the bloodstream. This paper aims to provide a comprehensive overview of the current research status regarding TEP RNA and cfRNA in liquid biopsies from various tumor types. Our analysis includes cancers of the lung, liver, pancreas, breast, nasopharynx, ovary and colon, as well as multiple myeloma and sarcoma. By synthesizing this information, we intend to establish a solid theoretical foundation for exploring potential applications of circulating RNA as a reliable biomarker for tumor diagnosis and monitoring.

The Functional Mechanisms of Toll-Like Receptor 3 and Its Implications in Digestive System Tumors

Toll-like receptor 3 (TLR3) is a prominent member of the Toll-like receptor (TLR) family and has the ability to recognize and bind intracellular double-stranded RNA (dsRNA). Once triggered by a viral infection or other pathological condition, TLR3 activates immune cells and induces the production of interferons and other immune response molecules. Additionally, TLR3 is considered an important immune modulator, as it can regulate cell apoptosis and promote anticancer immunity. The investigation and application of TLR3 agonists in digestive system tumors have attracted widespread attention and are regarded as a promising cancer treatment strategy with potential clinical applications. TLR3 expression levels are generally elevated in most digestive system tumors, and higher TLR3 expression is associated with a better prognosis. Therefore, TLR3 has emerged as a novel therapeutic target for digestive system tumors. It has been used in combination with chemotherapy, radiotherapy, and targeted therapy and demonstrated excellent efficacy and tolerability. This has provided new ideas and hopes for the treatment of digestive system tumors. This review discusses the mechanisms of TLR3 and its frontier research in digestive system tumors.