Moneghini L, Tosi D, Graziani D, et al. - Researchers sought to determine a possible correlation between the immunohistochemical expression of CD10 and CD34 (two progenitor/mesenchymal stem cell markers) in vascular malformations (vMs), which encompass a wide range of diseases often linked with somatic or, more rarely, germinal genetic mutations. Further, they examined their correlation with mutations in the PIK3CA/mTOR signaling pathway. They conducted this study on 58 samples of vMs and identified that in endothelial cells, there was significant expression of CD10 in PIK3CA-mutated samples vs samples without any mutation; this was particularly and even more consistently evident when compared with samples with mutation in other pathways. In contrast, the same PIK3CA-mutated samples had significantly reduced CD34 expression in endothelial cells when compared with samples either without any mutation or mutations in other pathways. Compared with samples with mutations in other pathways, samples with TEK/TIE2 mutation, a gene linked to the PIK3CA/mTOR pathway, showed a significant overexpression of endothelial CD10. Samples with PIK3CA mutation had significantly elevated CD10 expression in the stroma compared with samples with TEK/TIE2 gene or other gene mutations. Findings suggest an association between CD10 and CD34 expression in vMs with defined gene mutations. This discovery may have implications in diagnosis and therapy of these diseases.