Effect of PEG-8000 on tongue mucosal EGFR and cyclin D1 expression in 4 NQO-treated rats –The tongue sections were subjected to immunohistochemical analyses to assess changes in EGFR and Cyclin D1 expressions.

As shown (left Panel - Figure 3A and 3B), baseline EGFR expression in the tongue mucosa of 4NQO-rats was higher than that of control rats (p<0.00001). Topical application of PEG however, caused a significant decline in the expression of EGFR (p<0.005). Furthermore, topical PEG application to 4-NQO rats caused similar effects on the expression of Cyclin D1, one of the downstream effectors of EGFR (right Panel - Figure 3A and 3B).