Molecular subtypes of breast cancer have been useful in predicting prognosis and optimizing medical oncologic treatment and can be approximated by assessing combined estrogen, progesterone, and HER2 receptor status [1, 2]. Opto-acoustic (OA) imaging is a fusion of real time co-registered, interleaved laser optic and ultrasound imaging that shows dual functional findings (relative de-oxygenation of hemoglobin) and morphologic information (tumor angiogenesis) within and around breast masses using a hand-held opto-acoustic probe [3]. The goal is for OA to help distinguish benign from malignant lesions and to correlate with histologic grading. We anticipate that OA will prove to have this capability.