With the development of cancer treatments, it has become a popular research focus that mesenchymal stem (or stromal) cells (MSCs) have the functional mechanisms that influence cancer progression. One of the underestimated mechanisms is secretion of highly specialized double-membrane structures called exosomes. Mesenchymal stem cells generate several exosomes that may act as paracrine mediators by exchanging genetic information. MSC-derived exosomes are microvesicles ranging from approximately 60-200 nm in size and detected in various body fluids. It has been demonstrated that MSC-derived exosomes are involved in tumor growth, angiogenesis, metastasis, and invasion. Furthermore, emerging evidence suggests that as natural nanocarriers, MSC-exosomes are responsible for multidrug resistance mechanisms, reverse effect of radiation injury, and immune regulation, which can be used in clinical applications for cancer therapy. The present review aims to briefly describe the properties and biological functions of MSC-exosomes in cancer progression and its possible clinical applications in the future.

Chimeric antigen receptor‐ (CAR‐) T cell therapy is one of the most recent innovative immunotherapies and is rapidly evolving. Like other technologies, CAR‐T cell therapy has undergone a long development process, and persistent explorations of the actions of the intracellular signaling domain and make several improvements have led to the superior efficacy when anti‐CD19 CAR‐T cell treatments in B cell cancers. At present, CAR‐T cell therapy is developing rapidly, and many clinical trials have been established on a global scale, which has great commercial potential. This review mainly describes the toxicity of CAR‐T cell therapy and the challenges of CAR‐T cells in the treatment of solid tumors, and looks forward to future development and opportunities for immunotherapy and reviews major breakthroughs in CAR‐T cell therapy.

Circular RNAs (circRNAs) are a class of non‑coding RNAs that are generated via alternative back‑splicing, which connects the terminal 5' and 3'ends. Due to their unique loop structure, circRNAs are resistant to ribonucleases and more stable than linear RNAs. In vivo, they are usually highly conserved and stably expressed in tissue/developmental‑stage‑specific manners. Generally, circRNAs function as microRNA sponges and splicing regulators, as well as in protein binding and transcription. Some circRNAs contain open reading frames with internal ribosomal entry site elements and can thus encode specific proteins. Previously, circRNAs were thought to be erroneous splicing products or by‑products of mRNA splicing. With the development of the next‑generation sequencing techniques, it has become increasingly clear that circRNAs are abundantly widespread in eukaryotes and that they play significant roles in malignant tumor progression. The present review briefly introduces the biogenesis and functions of circRNAs, as well as summarizes recent research in several common malignancies. The present review also addresses the prospects of circRNAs in clinical applications.