(color online) Cryo-ET has potential as a clinical diagnostic technique on a single cell level. Platelets from control subjects and patients with cancer, annotated tomogram. (a) Three randomly selected annotated platelets from healthy donors. All of them have an intact marginal band of microtubules (blue) enclosing most of their granules (α pink, dense green) and mitochondria (red) inside. The plasma membrane is gray and the low-contrast vacuole-like (LCV) feature is yellow. (b) Three randomly selected annotated platelets from patients with benign masses. Their structures are similar to those shown in panel (a). (c) Three randomly selected annotated platelets from patients with invasive ovarian cancer. Their morphologies appear to be more heterogeneous compared with the six platelets in the other two panels. They seem to have more LCV, fewer and shorter microtubule filaments, and more mitochondria. Modified with permission from Wang et al., 2015.