PECAM1 and neoplasm: Consistent with prior evidence linking aberrant angiogenesis to tumor aggressiveness [12–16], our single-cell RNA sequencing identified the most aggressive tumor cell subgroup as highly enriched in angiogenesis pathways, with CD31 (PECAM1) emerging as a central endothelial marker associated with vascularization, angioinvasion, and poor prognosis [17–19].