KIF5B and varicocele: One study described that exosomal proteins annexin A2 (ANXA2), semenogelin-1 (SEMG1), transferrin (TF), and kinesin-1 heavy chain (KIF5B) were dysregulated in male patients with varicocele–a condition characterised by the formation of varicose veins within the scrotum which can often lead to infertility [64].