Protease-activated receptor 2 (PAR2) is a G-protein coupled receptor which is activated upon cleavage of its N-terminal region. PAR2 has been associated with many aspects regarding tumor progression, such as the production of pro-tumoral cytokines. Granulocyte colony-stimulating factor (G-CSF) is a cytokine essential to neutrophil production and maturation, and it is often overexpressed in tumors. In this study, we evaluated the ability of PAR2 to modulate G-CSF expression. PAR2 and G-CSF were significantly more expressed in metastatic (4T1 and MDA-MB-231) as compared to non-metastatic (67NR and MCF7) breast cancer cell lines. In addition, PAR2 stimulation by a synthetic agonist peptide significantly increased G-CSF gene expression in the metastatic cell lines. Knockdown of PAR2 in 4T1 cells decreased G-CSF expression and secretion. In addition, treatment of 4T1 with the commercial PAR2 antagonist, ENMD-1068, significantly decreased G-CSF expression. cBioPortal analyses of the TCGA database showed a significant co-occurrence of G-CSF and PAR2 gene overexpression in breast cancer samples. In conclusion, our data suggest that PAR2 contributes to G-CSF expression in breast cancer cells, possibly favoring tumor progression. (C) 2018 Elsevier Inc. All rights reserved.