| Immunostaining disclosed that p 63 , ABCG 2 and integrin alpha 9 were primarily expressed by the basal epithelial cells of limbus . ^^^ RT PCR showed higher levels of p 63 , ABCG 2 and integrin alpha 9 mRNA , but lower levels of K 3 , K 12 and connexin 43 expressed in the limbal epithelia than the corneal epithelia . ^^^ This work suggests that the basal epithelial cells of the limbus are p 63 , ABCG 2 and integrin alpha 9 positive , and nestin , E cadherin , connexin 43 , involucrin , K 3 , and K 12 negative , with relatively higher expression of integrin beta 1 , EGFR , K 19 , and enolase alpha . ^^^ |