<prompt> Which of the following oncogenes is a growth factor?fosmycjunsis  <response>: The sis oncogene is a growth factor. The protooncogene sis encodes the b chain of Platelet Derived Growth Factor PDGF. Ref: Robbins Illustrated Pathology, 7th Edition, Pages 293, 295; Cancer: Principles and Practice of Oncology, 6th Edition, Page 13 