Fig. 1

The CD70-CD27 axis in hematopoiesis and oncology. During normal hematopoietic development, expression of CD70 is tightly regulated and plays a role in priming, survival and differentiation for a subset of immune cells through NF-κB and c-Jun pathway activation via TRAF 2/5 leading. Alternatively, apoptosis can be induced by activating the caspase pathway via Siva. Reverse CD70 signaling can activate PI3K/Akt and MEK signaling pathways leading to regulation of cell expansion, differentiation and effector functions. In oncology CD70 and CD27 are frequently co-expressed on malignant cells which can deliver proliferation signals and a growth advantage to the malignant cells. Apart from improved growth, dysregulation of the axis can provide other tumor promoting effects via different signaling pathways. Figure created with BioRender.com. Abbreviations; CSC, cancer stem cell; HSC, hematopoietic stem cell; MEK, mitogen-activated protein kinase kinase; NFκB, nuclear factor kappa B; NK cell, natural killer cell; PI3K, phosphoinositide 3-kinase; sCD27, soluble CD27; TRAF 2/5, TNF receptor associated factor 2/5