RESUMEN
PURPOSE: The aim was to assess the expression stability of three commonly used reference genes, namely, ß-actin (ACTB), 18S ribosomal RNA (18S), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), in placental tissue obtained from pregnant women with polycystic ovary syndrome (PCOS) and healthy controls. METHODS: mRNA was isolated after delivery from the placentae of 10 PCOS and 10 control women with term, uncomplicated, singleton pregnancies. The expression of ACTB, 18S, and GAPDH was analyzed using real-time polymerase chain reaction (RT-PCR). Gene expression stability was evaluated with the RefFinder, GeNorm, Normfinder, BestKeeper, and Delta-Ct tools. RESULTS: ACTB was ranked as the most stably expressed gene, followed by 18S. The expression of GAPDH varied considerably in both studied groups, while it was increased in PCOS versus controls (5.3-fold, p < 0.05). CONCLUSIONS: ACTB is an appropriate reference gene for placental gene expression studies in women with PCOS, whereas GAPDH is unfit for such a role, as its placental expression is increased in PCOS.