ROBO1 and Epiretinal membrane: The results of the semi-quantitative RT-PCR analysis demonstrate that the expressions of Slit2 mRNA (Fig 10B, P <0.05), Robo1 mRNA (Fig 10C, P< 0.05), and VEGF mRNA (Fig 10D, P < 0.05) were significantly higher in the FVMs of the six patients with PDR than in the membranes of the six patients with idiopathic epiretinal membranes (Fig 10).