IL1B and Merkel cell skin cancer: Next, we analyzed the functional effects of the EVs’ cargo transferred from MCC cells, including miR-375, on fibroblasts by measuring the mRNA expression of CAF markers, i.e., ACTA2, CXCL2 and IL1B. Consistent with the highest miR-375 uptake, CAF markers, especially ACTA2, also exhibited highest expression in fibroblasts under DC conditions (Fig. 3e to h).