Survey of low ER-positive expression and its correlation with other clinical and pathological factors in breast cancer

Introduction: Breast cancer is the most common cancer in women. Owning to the prominent role of biomarkers in molecular classification of breast cancer in recent years, evaluation of estrogen receptor (ER), progesterone receptor (PR), and Her2/neu seems to be required for prognosis and treatment of patients. Material and Methods: One-hundred twenty two patients with primary breast carcinoma were selected and immunohistochemistry staining for ER, PR, and Her2/neu were performed on representative paraffin blocks. ER level can be semi-quantified by immunohistochemistry using the H-score. The score, given as the sum of the percent of tumor cells staining multiplied by the intensity level, ranges from 0 to 300 as low, intermediate, and high grades. The statistical association of ER expression with the level of PR and Her2/neu, tumor size, necrosis, microscopic grade, vascular invasion, and lymph node involvement were analyzed using SPSS16 software. Results: Results showed that among 122 studied patients, 44.3% were in the low ER-positive group where most of these cases (22.1%) were Her2/neu negative. Although there was a reciprocal interplay between the expression of ER and Her2/neu, increased expression of ER had a direct relation with PR level. However, there was no statistical relation between ER level with age, tumor size, necrosis, microscopic grade, vascular invasion, and lymph node involvement. Discussion: The study clearly indicated that low ER group encompasses the high frequency of breast cancer patients. Furthermore, the most cases of low ER patients were in Her2/neu negative group.