Figure 8B showsthe average normalized Raman spectra of membranes and mitochondriain breast cancer cells, triple-positive HER2MCF-7, HTB-30, and AU-565(C) overexpressing HER2, the normal cells (MCF-10A) (HER2 at the normallevel), and triple-negative aggressive breast cancer (MDA-MB-231).One can see that the highest concentration of cytochrome c represented by the vibration at 1584 cm–1 is locatedin mitochondria and supports the results reported recently1. Here, CYCS is linked to breast cancer.