TGFB2 and posterior polymorphous corneal dystrophy: Interestingly, here we have found that in PPCD the proliferation of aberrant cells is not associated with lower, but rather significantly higher TGF-β2 levels in AH compared to the control group; however, in 81% of samples the levels of TGF-β2 do not exceed 500 pg/ml, a concentration that was able to reduce the proliferation of cultured human corneal endothelial cells [43].