GM-CSF—a specific mediator of cellular transformation in a paracrine manner.A and B, wound healing and transwell migration assay of NIH3T3 cells incubated with conditioned media (CM)/GM-CSF depleted CM collected from RAW 264.7-PELP1 overexpression clones. The left panels represent percentage of wound closure and the number of migrated cells; the right panels show representative images of wound healing and transwell migration assay of NIH3T3 cells, respectively. C, soft agar colony formation assay; Left, the total number of transformed NIH3T3 cells/well when incubated with CM/GM-CSF–depleted CM collected from RAW 264.7-PELP1 overexpression clones for 1 to 2 weeks. Right, representative images captured by phase contrast microscope connected to a camera. D, quantitative RT–PCR analysis of CSF-2–specific receptor subunit alpha (CSFRa) expression on various cell lines. GM-CSF, granulocyte–macrophage colony-stimulating factor.