Analysis of the immunohistochemical expression of mammaglobin A in primary breast carcinoma and lymph node metastasis.

Mammaglobin A is a specific marker of the normal and neoplastic mammary tissue that usually is detected by RT-PCR. Few data are available about the immunohistochemical expression of this marker in mammary carcinoma and about the significance of the positive reaction. Our purpose was to investigate the sensitivity of the mammaglobin expression in breast cancer and to determine its correlations with conventional prognostic parameters. There were investigated 47 patients with breast carcinoma, and slides from paraffin blocks were stained with an antibody against mammaglobin. The immunohistochemical reaction was scored based on the percentage of positive tumor cells in both primary tumors and lymph node metastasis. Positive reaction for mammaglobin was found in the normal mammary tissue adjacent to the tumor in all cases, in 78.72% primary breast carcinoma, and in 58.06% of cases with lymph node metastases. A significant correlation was found between the mammaglobin expression in the primary tumor, grade, and lymph node status, but not with the age of the patient, pathologic subtype of carcinoma and stage of the tumor. The ductal in situ carcinoma associated to the invasive tumor did not influence significantly the prognostic value of mammaglobin expression. Out results suggest that mammaglobin is a sensitive marker of breast carcinoma, it defines a subgroup of patients with better prognosis and is a useful method to detect breast cancer metastases.

Immunohistochemical expression and significance of epidermal growth factor receptor (EGFR) in breast cancer.

Breast cancer is a heterogeneous disease that includes several molecular types, characterized by the expression profile of sex hormone receptors, HER2 protein, cytokeratin 5, p53, and Bcl-2. EGFR is an additional marker predominantly expressed by basal-like carcinoma, but its significance in the other types is not completely understood. The aim of this study was to analyze the immunohistochemical expression of EGFR and its relationships with other factors of prognosis. There were investigated benign lesions and 84 cases with invasive breast carcinoma that were submitted first to the molecular classification. Next, we performed the staining for EGFR and two patterns of the final product of reaction were described. EGFR expression was found in 41.66% of the cases with basal-like carcinoma, in 50% of the cases with luminal B carcinoma, and in 21.42% of the cases with HER2 overexpression. A significant correlation was found between EGFR expression and degree of differentiation and distant metastasis. No significant correlation was found with the lymph node status, excepting for the basal-like carcinoma in which an inverse correlation was noticed. Our results suggest that EGFR expression by tumor cells of the breast cancer defines a specific subset of tumors with poor prognosis and potential resistance to the adjuvant therapy.