Electron cryotomography reveals ultrastructure alterations in platelets from patients with ovarian cancer

Significance Platelets are known to be both numerically and functionally altered in some patients with cancer. However, structural differences in the platelets from these patients have not been studied. Here we use electron cryotomography to reveal that, compared with control donors, the microtubule system and the mitochondria of platelets from patients diagnosed with ovarian cancer are significantly different. This finding suggests the potential of electron cryotomography as a technology to detect structural biomarkers of diseases affecting platelets. Thrombocytosis and platelet hyperreactivity are known to be associated with malignancy; however, there have been no ultrastructure studies of platelets from patients with ovarian cancer. Here, we used electron cryotomography (cryo-ET) to examine frozen-hydrated platelets from patients with invasive ovarian cancer (n = 12) and control subjects either with benign adnexal mass (n = 5) or free from disease (n = 6). Qualitative inspections of the tomograms indicate significant morphological differences between the cancer and control platelets, including disruption of the microtubule marginal band. Quantitative analysis of subcellular features in 120 platelet electron tomograms from these two groups showed statistically significant differences in mitochondria, as well as microtubules. These structural variations in the platelets from the patients with cancer may be correlated with the altered platelet functions associated with malignancy. Cryo-ET of platelets shows potential as a noninvasive biomarker technology for ovarian cancer and other platelet-related diseases.