Emerging evidence indicates that mesenchymal stem cells (MSCs) play an important role in tumour progression. MSCs from different sources may have distinct effects on tumours. Tumour-associated MSCs (TA-MSCs) promote tumour progression, including growth, angiogenesis, invasive ability, and metastasis of tumour cells, by secreting some growth factors, exosomes, or by other mechanisms. Human umbilical cord-derived MSCs (hUCMSCs) do not promote proliferation and also inhibit the migration of tumour cells. In addition, they inhibit tube formation in human umbilical vein endothelial cells (HUVECs).

MSCs are also engaged in the immunomodulatory function of B cells, dendritic cells, macrophages, and myeloid-derived suppressor cells (MDSCs). Therefore, it is easily understandable that MSCs interact with immune cells and other cells in the tumour microenvironment (TME). It is of profound significance to explore the role of MSCs in tumour progression and therapy.

In this Special Issue, we invite investigators to contribute original research articles as well as review articles that provide novel insights into the role of MSCs in tumours and tumour immunity, which could meaningfully contribute to clinical tumour diagnosis and treatment.

Potential topics include but are not limited to the following:

• MSCs from various sources, including bone marrow-derived mesenchymal stem cells (BMMSC), TA-MSCs, hUCMSCs, etc.
• How MSCs regulate tumour progression
• Bidirectional regulation between MSCs and tumour cells or immune cells
• The biological effects of MSCs on tumour cells or immune cells
• Tumour immunotherapy of MSCs
• The effects of MSCs on tumour drug resistance
• MicroRNAs, exosomes, or other molecules regulating the MSCs-mediated tumour or tumour immunity progression
• MSCs and immune check-points
• The association between MSCs and markers or prognosis