Inducing Polyclonal Eag1-Specific Antibodies by Vaccination with a Linear Epitope Immunogen and Its Relation to Breast Tumorigenesis

Ether à-go-go 1 (KCNH1, Kv10.1) (Eag1) is a voltage-gated potassium channel, which is commonly overexpressed in tested breast cancer patients. This occurrence makes it a potential molecular marker and a promising tool for breast cancer diagnosis and therapy. In order to explore protective or specific polyclonal antibodies for further research, potential linear epitopes from Eag1 were collected by sequence alignment. The sequence was synthesized and then coupled to the carrier protein keyhole limpet hemocyanin (KLH) for animal immunization. Polyclonal antibodies against Eag1 were produced and purified from the rabbit antisera. Enzyme linked immunosorbent assay (ELISA) and western blot were performed to characterize their specificities. Immunohistochemical staining was carried out on normal and cancerous breast tissue sections using the purified polyclonal Eag1-specific antibodies. The results indicate that the overexpression of Eag1 might be associated with an increased risk of progression to breast cancer (Grade 1 tissue = 57.89%;Grade 2 tissue = 92.59%;Grade 3 tissue = 100%). These results also suggest that Eag1 gene is a putative growth-promoting gene that might be involved in breast tumorigenesis and development. Eag1 might further be represented as a potential target for some human diseases treatment.