Human Epidermal Growth Factor Receptor 2 (HER2) Expression in Colorectal Cancer and Its Clinical Significance among Jordanian Patients.

IntroductionThe expression of Human Epidermal Growth Factor Receptor-2 (HER2/neu) has shown significant therapeutic implications in malignancies, particularly in breast and gastric cancer. Therefore, the interest in studying HER2 in other malignancies, including colorectal cancer (CRC), has increased. However, the prevalence of HER2 overexpression in CRC remains debatable, with conflicting data. To address this uncertainty, this study aimed to investigate HER2 expression in CRC in Jordanian patients and to assess its association with clinicopathological characteristics, as well as the survival outcome.MethodsSixty-nine formalin-fixed, paraffin-embedded tissue blocks of CRC cases were included along with their corresponding patient's clinicopathological data. Tissue-microarray (TMA) were constructed and stained using anti-HER2/neu monoclonal antibody. HER2 scoring was performed using the HERACLES criteria. Fisher's exact test/Chi-squared test were used to investigate the association between HER2 scores and the clinicopathological data. Survival analysis was evaluated using Kaplan-Meier curves.ResultsHER2/neu positivity of any degree was expressed in 30 cases (43.5%). Twenty-five cases (36.2%) were scored 1 + and 4 (5.8%) scored 2+. Only one case (1.5%) was scored as 3+, representing the single positive case. In comparison, 39 cases (56.5%) showed no HER2/neu protein expression and were scored as (0). Two of the four cases that were scored (2+) required FISH testing to confirm the positivity for HER2 overexpression, which was not available. No significant associations were found between HER2/neu expression and clinicopathological parameters or survival rates. However, cases with either 2+ or 3+ HER2/neu scores were associated with worse overall survival (OS) and event-free survival compared to cases with a score of 1+ or no expression (score 0).ConclusionsThe prevalence of HER2/neu overexpression in CRC among Jordanian patients is low, with only 1.5% of the study sample exhibiting HER2/neu overexpression. A trend towards poor outcome was observed in patients with HER2/neu overexpression.