We confirm the utility of all candidate reference genes and miRNAs but especially of OAZ1 and hsa-miR-6835-3p by measuring their expression abundance (Fig. 3a and Fig. 4c, d) and stability (Fig. 3b, c, d, e and Fig. 4f, g, i, j) in serum exosomes of an independent cohort of ovarian cancer patients and of healthy control individuals (n = 10 each group, Fig. 3). Here, OAZ1 is linked to ovarian cancer.