de la Fouchardière A, et al. - Researchers in this analysis evaluated the nuclear β-catenin immunohistochemical expression in a large group of deep penetrating nevi (DPN) and in the 4 most frequent differential diagnoses of DPN: “blue” melanocytic tumors, Spitz tumors, nevoid and SSM melanomas, and pigmented epithelioid melanocytomas (PEM). Findings revealed that the expression of nuclear β-catenin in a dermal melanocytic tumor is an argument for its classification as DPN, regardless of the expression of CCND1. This antibody can be helpful as a screening tool in ambiguous cases and early combined DPN lesions. In a subset of malignant melanomas with CTNNB1 mutations, β-catenin may also be expressed.