Overexpression of type I growth factor receptors in pterygium

To evaluate the expression of the type I growth factor receptor family [epidermal growth factor receptor (EGFR), ErbB2 and ErbB3] by the epithelial cells in pterygium.

Immunoflourescent staining and Western blotting were performed to detect the expression pattern and quantity of EGFR, ErbB2 and ErbB3 proteins in the epithelia of 15 patients with primary pterygium and 12 subjects with normal conjunctiva.

In immunofluorescent staining, the EGFR protein was present in the basal cells while the ErbB2 and ErbB3 were expressed by the superficial cells in normal conjunctival epithelium. Of the pterygium cases 15, 11 were stained by EGFR, ErbB2 and ErbB3 in the full thickness of the epithelium and showed stronger staining compared with the control group. Four of them showed a similar staining pattern to the normal conjunctiva group. The density of protein bands detected by Western blotting for all three growth factor receptors was consistent with the immunofluorescent staining. Compared with normal conjunctiva, stronger protein bands of these three receptors were found in all of the pterygium specimens, in which EGFR, ErbB2 and ErbB3 were expressed in the full thickness, as shown by immunofluorescent staining.

The increased expression of EGFR, ErbB2 and ErbB3 proteins was present in pterygium, which indicated that pterygium is a disorder with abnormal proliferation. The abnormal expression of EGFR, ErbB2 and ErbB3 by the epithelium and the communication with cytokines in the stroma in pterygium may be a key pathogenic factor in this disorder.