Elevated PlGF levels have been detected in patients with reduced kidney function.25 Moreover, many other cell types such as keratinocytes, cardiomyocytes, retinal pigment epithelial cells, bronchial epithelial cells, and tumor cells have been reported to express PlGF in pathological conditions.26 Placental growth factor stimulates pathological angiogenesis by upregulating tumor necrosis factor α and monocyte chemotactic protein-1.27 The findings of the present study also confirm that PlGF-immunopositive cells are highly expressed in ACR-exposed kidney tissue. This evidence concerns the gene CCL2 and neoplasm.