NIH-funded, multicenter, prospective, cross-sectional study examining the unique mechanisms of ischemic stroke in cancer patients through cutting-edge hematological and cerebrovascular ultrasound biomarkers. Three groups of patients will be enrolled. Group 1 will be patients with active solid tumor cancer and acute ischemic stroke. Group 2 will be patients with acute ischemic stroke and no cancer. Group 3 will include patients with active solid tumor cancer and no stroke. Patients in Groups 2 and 3 will be matched individually to patients in Group 1 and will serve as controls.