Blood-based liquid biopsies are considered a screening approach for early cancer detection. Sequencing technologies enable in-depth analyses of nucleic acids, including mutant cell-free (cf) DNA in the plasma. However, in the blood of patients with early-stage cancer the detection level of mutant cfDNA is relatively low, and complicated by the natural presence of noncancer cfDNA mutants attributed to aging-related processes. Consequently, analysis of methylated cfDNA patterns and alternative approaches such as tumor-educated platelets are gaining traction for the detection of early-stage tumors. Here, we dissect the use of platelet RNA as a potential biomarker for the development of early-stage, pan-cancer blood tests.