“…In contrast, the SC-containing limbal epithelium has a high proliferative potential in different cultures [12][13][14][15], and their in vitro proliferation is resistant to the inhibition by tumor-promoting phorbol esters [13,16,17]. Furthermore, limbal basal epithelial cells express cytokeratin 19 [18], and integrin a9 [10,19], and preferentially express such progenitor markers as p63 [20], especially its ∆Np63a isoform [21,22], Bcrp1/ABCG2 [10,[23][24][25], and N-cadherin [26].…”