The Expressions of Tyrosine Kinase Receptors, EphA2, c-met and c-erbB-2 in the Human Breast

ABSTRACT

BACKGROUND: Tyrosine kinase receptor (TKR) is an important protein for normal-development, growth and tumorigenesis in human tissues. The purpose of this study was to evaluate the effect of TKR in the progression of breast cancer. METHODS: The expressions of EphA2, c-met and c-erbB-2 were examined, by using immunohistochemical methods and RT-PCR, in samples of breast tissue that included 111 samples of normal epithelium, 34 samples of ductal carcinoma in situ (DCIS), and 109 samples of invasive ductal carcinomas (IDC). The results were compared with the prognostic parameters of breast cancer including the tumor grade, growth pattern, lymph node metastasis and the expressions of ER, PR, p53 and Ki-67. RESULTS: The protein expressions of the three TKRs were higher in DCIS and IDC than in normal epithelium. The protein expression of EphA2 was correlated with a tumor grade, a labeling index of Ki-67, and the protein expression of c-met. Overexpression of c-erbB-2 was correlated with lymph node metastasis. The mRNA levels of the three TKRs were correlated with each other in normal tissue and IDC. The level of c-met mRNA was higher in the low grade tumors. CONCLUSIONS: The three TKRs may play roles in the tumorigenesis of human breast cancer. The overexpressions of EphA2 and c-erbB-2 may be a poor prognostic parameter in breast cancers.