FST and cancer: In the non-cancer group only, sHER-2neu, follistatin, and leptin were significantly higher in the cystic fluid than in the serum (5.3 vs. 3.2 ng/mL; p = 0.026,0.7 vs. 0.3 ng/mL, p = 0.005, and 2.7 vs. 2.1 ng/mL; p = 0.026, respectively), and PDGF-AB/BB was significantly higher in the serum (0.1 vs. 0.4 ng/mL; p = 0.039).