NR4A1 and breast carcinoma: Although our sensitivity analyses addressed the potential confoundedness of comorbidities and symptoms from surgery, there may be other potential confounders, such as surgery types, other treatments, lifestyle factors, and social support, that we were not able to measure and include in our models.61 Furthermore, we studied women with hormone receptor–positive early-stage breast cancer who were treated in a single cancer center in the southern US.