CXCR4 and cancer: SDF‐1 is a major substrate for CD26/DPP‐4 peptidase.14, 29 The resulting failure of transduction of the downstream signaling of CXCR4, an SDF‐1 receptor present on the target cells, attenuates hematopoietic stem/progenitor cell homing,30 HIV infection,31, 32 and cancer cell invasion.33, 34, 35, 36 Given these observations, we speculated that the attenuated stromal CD26 expression may influence SDF‐1 autocrine signaling and the myofibroblastic state in CAFs.