Correlation Between HER-2 Gene Amplification or Protein Expression and Clinical Pathological Features of Breast Cancer.

OBJECTIVE: The incidence of breast cancer in females is gradually increasing. Expression of HER-2 gene and protein is critical for predicting the prognosis of breast cancer. This study examined amplification of HER-2 gene and protein expression in breast cancer patients to analyze their correlation with clinical and pathological features.

MATERIALS AND METHODS: Specimens of breast gland tissues were collected from breast cancer patients for measuring HER-2 protein expression by immunohistochemistry (IHC) method. Fluorescent in situ hybridization (FISH) measured HER-2 gene amplification. The consistency of HER-2 protein and gene expression was analyzed in addition to their correlation with clinical and pathological features of patients.

RESULTS: Thirty-six percent patients showed negative expression of HER-2 protein, and 9%, 32%, and 23% of them had positive expression to different levels (+, ++, and +++). Forty percent patients were positive for HER-2 gene amplification, including 3, 21, and 14 cases of (+), (++), and (+++) patients. Expression of HER-2 protein was highly correlated with HER-2 gene amplification (r = 1.262; p < 0.05). Both parameters were correlated with tumor size, differentiation grade, lymph node metastasis, and TNM stage (p < 0.05).

CONCLUSIONS: Combined assay of IHC and FISH for detecting HER-2 protein or gene amplification in breast cancer tissues showed their correlation with tumor size, differentiation grade, lymph node metastasis, and TNM stage.