In another study, in addition to CTNNB1 mutations and beta-catenin protein expression analyses, cytogenetic analysis of pilomatricoma tissues was carried out and revealed that approximately 60% of pilomatricomas had trisomy 18 in very low proportions varying from 0.5% to 2.8%, in the neoplastic epithelial cells of the pilomatricomas, but not in the surrounding mesenchymal or epithelial tissue [47]. This evidence concerns the gene CTNNB1 and pilomatrixoma.