CCL2 and fibromyalgia: Other relevant markers are monocyte chemoattractant protein-1 (MCP-1), involved in immune cell recruitment (Deshmane et al., 2009), and vascular endothelial growth factor (VEGF), which affects vascular permeability and neuroinflammatory respones (Takahashi and Shibuya, 2005), and have likewise been linked to fatigue in adults with cancer, fibromyalgia, and chronic fatigue syndrome (Himbert et al., 2019; Groven et al., 2020).