<prompt> A 68-year-old man has a long history of prostate cancer that was metastatic at the time of diagnosis. Over the past 2 months, he has had significant weight loss, loss of appetite, and loss of energy. His current spectrum of conditions can be attributed to which of the followingPlatelet-derived growth factorFibroblast growth factorInterleukin-2Tumor necrosis factor-a  <response>: Cachexia, or wasting due to cancer manifests with weakness, weight loss, anorexia, anemia, and infection. The principal cytokine responsible for such changes is tumor necrosis factor-a TNF-a. -Both platelet-derived growth factor and fibroblast growth factor are involved in wound healing. -Interleukin-2 IL-2 is an immuno-stimulating cytokine produced by activated T cells. -Vascular endothelial growth factor is impoant in the proliferation of blood vessels in a growing tumor. 