Nicola Fusco, MD, University of Milan, Milan, Italy, discusses the findings of a study investigating the clinical value of phosphatase and tensin homologue (PTEN) status as a biomarker in patients with breast cancer. The study analyzed protein expression data from 608 patients and gene expression data from 3929 patients with breast cancer. The study reported that tumors with reduced PTEN expression were enriched for HER2+ and triple-negative subtypes compared to wild-type PTEN tumors. Low PTEN protein expression, but not gene expression, was related to worse overall survival in HR+/HER2+ tumors compared to HR+/HER2- tumors. Overall, the study concluded that analysis of PTEN protein and gene expression could be used in risk assessment when evaluating patients with HR- and HER2+ breast cancer. This interview took place at the virtual European Society for Medical Oncology (ESMO) Breast Cancer Congress 2021.