This effect was associated with a substantial decrease in PlGF-positive melanoma cells, reinforcing the concept that either a PlGF/VEGFR-1 autocrine loop or VEGFR-1 activation by PlGF produced by other cells present in the tumor microenvironment, including tumor-associated macrophages, may favor invasion of the surrounding tissues and acquisition of a bone tropism. Here, PGF is linked to neoplasm.