Breast Cancer Molecular Subtypes Defined by ER/PR and HER2 Status: Association with Clinicopathologic Parameters in Ivorian Patients.

Background: Breast cancer is a heterogeneous disease that represents a major public health problem. The immunohistochemical determination of breast cancer subtypes with regard to estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor (HER2) status can contribute to improved selection of therapy and patientcare. The purpose of this study was to determine the prevalence of the molecular breast cancer subtypes and to assess their associations with classical clinicopathologic parameters for better therapeutic decisions in women with breast cancer in the Ivory Coast.

Materials And Methods: Formalin- fixed and paraffin-embedded blocks of patients diagnosed with primary breast carcinoma were subjected to immunohistochemical assay for the assessment of ER/RP and HER2 expression. The one-way analysis of variance evaluated the difference between breast cancer subtypes and mean age of patients. The Chi-square Test was used to compare standard clinicopathologic prognostic parameters with tumor subtypes.

Results: Among 302 patients, 57% were premenopausal and 43% were postmenopausal. The invasive ductal carcinoma not otherwise specified (IDC NOS) (82.8%) was the most frequent histological type, and the tumor grade 2 (56%) was predominant followed by grade 3 (20.9%). The proportion of positivity of ER, PR, and HER2 was 56%, 49%, and 15.6%, respectively. Half of patients of this study (51.6%) had luminal A breast tumor type followed by TN (32.1%). Other subtypes were luminal B (10.1% ) and non-luminal HER2+ (6.3%).

Conclusions: The findings of the present study are in line with the literature and should assist in management of breast cancer in our country.