Imaging features of estrogen-negative breast cancers: a correlation study with human epidermal growth factor type II overexpression

Background: Estrogen-negative breast cancers have different clinical course, prognostic features and treatment response in comparison to estrogen receptor-positive (ER-positive) breast cancers. Human epidermal growth factor receptor 2 (HER2) oncoprotein has found to have a pivotal role in natural cell growth and cell division and is suggested to be directly related to tumor invasiveness in breast cancer patients. The purpose of this study was to retrospectively assess the mammography, ultrasound, and magnetic resonance imaging (MRI) features of estrogen negative breast cancers with and without overexpression of HER2/neu receptor. Methods: In this cross-sectional retrospective study, mammographic, ultrasound and MRI features as well as HER2 status were assessed in patients with ER-negative breast cancer that were referred to Cancer Institute of Imam Khomeini Hospital Complex in Tehran from October 2015 to October 2017. Clinicopathologic data and mammography, ultrasound, and MRI features were reviewed and were correlated with HER2 status of estrogen-negative tumors. Results: Of the 172 patients with ER-negative breast cancer, 101 patients were positive for HER2/neu receptor (58.8%). There was a significant correlation between HER2-positivity and tumor type (P=0.004). Among estrogen negative breast cancers, significant association were found between HER2 and tumor histologic grade (P=0.024) and TNM stage (P=0.021). HER2-positive tumors were more likely to present with microcalcification (P=0.007) and have irregular shapes (P=0.034) in mammography than HER2-negative tumors. No association was found between HER-2 status and tumor size, shape, margin, posterior feature, halo or orientation of the tumor in ultrasound. We also found no correlation between HER2 status and MRI features including mass shape or margin, internal enhancement pattern or curve type among estrogen-negative breast cancers. Conclusion: Findings of this study showed that among estrogen-negative breast cancers, HER2/neu positive tumors are more likely to be diagnosed at higher stage and have higher histologic grade at the time of diagnosis. Tumor mass shape and microcalcification in mammography are found to be associated with HER2 status among patients with estrogen-negative breast cancer.