CCL2 and obesity due to melanocortin 4 receptor deficiency: Therefore, the present study involved the establishment of a nude mice model of obesity, which was established and injected with PC-3 cells, and a co-culture model of BMA and PCa cells in vitro to explore whether high concentrations of PA could activate the GPRs/KLF7/CCL2 pathway in BMA, thereby leading to prostate cancer growth and metastasis of the bone marrow.