LAUSR

AIMS Vascular malformations (vMs) encompass a wide range of diseases often associated with somatic or, more rarely, germinal genetic mutations. A mutation in the PIK3Ca/mTOR pathway is more often involved in various vMs. CD10 and CD34 are cellular markers that may play a role in mesenchymal differentiation and proliferation. The aim of our study was to find a possible link between the immunohistochemical expression of CD10 and CD34 in vMs and their relationship with mutations in the PIK3CA/mTOR signaling pathway. METHODS AND RESULTS Our study on 58 samples of vMS showed that in endothelial cells CD10 was significantly expressed in PIK3CA mutated samples compared to samples without any mutation (p<0.05), especially and even more consistently when compared to samples with mutation in other pathways (p <0.0001). Conversely, in the same PIK3CA mutated samples, CD34 expression in endothelial cells was significantly reduced compared to samples either without any mutation or mutations in other pathways (p<0.05 and p<0.0005). Compared to samples with mutations in other pathways a significant overexpression of endothelial CD10 was also found in samples with TEK/TIE2 mutation, a gene linked to the PIK3CA/mTOR pathway (p<0.01). However, CD34 expression was not altered. In samples with PIK3CA mutation, the CD10 expression was significantly increased in the stroma as compared to samples with TEK/TIE2 gene or other genes mutations (p<0.05). CONCLUSION Therefore, CD10 and CD34 immunohistochemical profile could suggest/support the presence of mutations in PIK3CA/mTOR pathway in samples of vMs.