The expression of HPV-16 E5 protein in squamous neoplastic changes in the uterine cervix

To investigate the expression of human papillomavirus type 16 (HPV-16) E5 p rotein in squamous neoplastic changes in the uterine cervix, the specific E 5 antibody was generated and used to identify the expression of E5 protein in 40 cases of HPV-16-positive tissues and 5 previously identified HPV-nega tive normal cervical tissues. The results revealed that E5 protein was prim arily expressed in the lower third of the epithelium in low-grade squamous intraepithelial lesions (SILs) and throughout the whole epithelium in high- grade SILs. In invasive squamous carcinoma, 60% of HPV-16-infected cancers which contained the episomal viral genome had the E5 gene, and could expres s E5 protein which was located throughout the whole epithelium. Previously, we documented the expression of type I growth factor receptors [ERBB1/EGFR (epidermal growth factor receptor), ERBB2, ERBB3 and ERBB4] in the full ra nge of cervical neoplasias by immunohistochemistry assay. Hence, in this st udy, we extensively analyzed the correlation between the expression of E5 p rotein and the expression of type I growth factor receptors. Among 40 HPV-1 6-infected cervical neoplasias, we found that the expression of E5 protein was significantly correlated with either the expression of the ERBB1 or the ERBB4 receptor.