Notably, gene clusters of PRMT1/PRMT5 and DDAH1/DDAH2/ARG2 persisted, while other gene tree relationships and expression significances differed between the two comparisons: normal tissue versus stage I/II ovarian cancer (Fig. 5A) and stage I/II versus stage III/IV ovarian cancer (Fig. 5B). Here, DDAH2 is linked to ovarian cancer.