FLT4 and diabetic retinopathy: A recent study investigating the lymphatics in diabetic retinopathy detected the expression of LEC markers, such as VEGFR3 and Prox-1, in excised human specimens (Loukovaara et al., 2015), providing the first clinical evidence that abnormal lymphatic growth, in addition to pathological microvascular remodeling, occurs in diabetic retinopathy.