Figure 4. Expression level of cell differentiation marker CK3, stem cell marker ABCG2 and undifferentiated cell marker p63, determined with reverse transcription polymerase chain reaction (RT–PCR) of limbal epithelial cells cultured in supplemental hormonal epithelial medium (SHEM), keratinocyte serum-free medium (KSFM), and Epilife. One way ANOVA was performed.