Background: Overexpression of human epidermal receptor protein-2 (HER2) is correlated to a poor prognosis in breast cancer (BC) patients who respond well to anti-HER2 therapy. Objective: Therapeutic procedures for treating HER2-positive breast cancer (BC) patient address HER2 protein. According to reports, the expression of HER2 oncogene and its relationship to clinicopathological factors in BC patients is yet unknown. Patients and methods: The present study involved 50 patients who were diagnosed histologically with invasive primary breast carcinoma. The PR, ER, and HER2 immunohistochemistry testing was conducted on the formalin fixed paraffin-embedded blocks of patient's breast tissue. The relationship between HER2 status and clinicopathologic diagnostic characteristics was investigated using analysis of variance and the Chi-Square Test. Results: Invasive lobular carcinoma (ILC) was the most common histological type, accounting for 86% of cases. The highest percentage of patients was grade II (66.7 %), tumour size (2-5) cm accounted for 73.3 % of cases, and lymph node metastases were present in 84 %. The majority of the individuals were diagnosed at stage II (66.7 %). The majority of patients had moderate Nottingham prognosis index (66.7 %). 60 % and 33.3 % of women tested positive for the estrogen and progesterone receptors, respectively. 53.3 % of the women tested positive for HER2. Histological type (p = 0.049*) and histopathology grade (p = 0.002**) were both significantly associated with HER2 overexpression. Conclusion: HER2 positive expression could produce further evidence about the inadequate diagnosis of BC and could be utilized for pre-choice of BC patients with HER2-overexpressing who demonstrated resistance to hormonal treatment.