RRM2 and cancer: RRM2 associates with RRM1 to form an active RR and its accumulation plays a central role in controlling RR activity.27 RRM2 is known to play an active role in tumorigenesis28 and is a prognostic factor for cancers such as colon, breast and pancreas.29–31 These data suggest that these three genes may be involved in ACC pathogenesis and aggressiveness.