[Her2-Neu expression in ductal adenocarcinomas of the breast gland: correlation with histopathological parameters and estrogen receptors' expression in Mexican patients].

Background: Breast cancer is a general health problem that annually produces 400,000 deaths worldwide. Its early diagnosis leads to high cure rates; nevertheless, in Mexico City this happens rarely. Her2-Neu is an oncogene that is expressed on breast cancer cells, with aggressive behaviour and metastasis. In the United States 20 to 30% of the patients present an over-expression of this protein. This phenomenon has been used as a prognostic parameter and as a predictive and indication factor for therapy with monoclonal antibodies directed against this protein and for therapy with taxanes.

Objective: To know the biology and distribution of Her2-Neu expression in Mexican breast cancer patients in order to evaluate its potential as a prognostic and predictive factor in the treatment of the breast cancer.

Patients And Method: In the cases of invasive ductal adenocarcinomas of the breast we compared by immunohistochemistry the Her2-Neu and estrogen receptor expressions with the histopathological characteristics. The results were evaluated statistically.

Results: We found 122 cases of breast adenocarcinoma, from which we evaluated 108 for fulfilling the selection criteria of invasive ductal adenocarcinoma. Patient's mean age was 51.8 +/- 13.2 years. The mean tumour diameter was 3.5 +/- 2.0 cm and the mean number of lymph nodes with metastasis was 6.8. The Her2-Neu (score 2+ and 3+) expression was found in 36.1% of the patients. The tumour diameter and the presence of metastatic disease had strong relation with the Her2-Neu expression level. We did not find correlation with the differentiation level, the patient's age and the presence or absence of oestrogen receptors.

Conclusions: Since the percentage of patients with Her2-Neu expression is high (36.1%) and there is a close relation between Her2-Neu expression, the tumour size and the presence of lymph node methastasis, the determination of the oncoprotein expression could allow a more detailed prognosis and the treatment with immunotherapy and anthracyclines in order to influence the course of the breast cancer cases.