Investigating the role of tumor-infiltrating lymphocytes in advanced HER2-positive breast cancer

Giant strides in the development of HER2-targeted agents have drastically improved outcomes for patients diagnosed with HER2-amplified breast cancer. Despite this, most patients who develop a recurrence inevitably die from their disease. More recently, anti-tumor adaptive T cell immune responses have been shown to be able to significantly influence both prognosis as well as response and benefit to therapies in early stage disease (1-3). Analyses assessing the role of tumor-infiltrating lymphocytes (TIL) in the setting of advanced HER2-positive breast cancer are only just beginning to emerge.