Soft Tissue Tumors

In reticuloangioendotheliomas, 38% of cases have YAP1 rearrangements, mainly YAP1 fusions. This fusion leads to localization of YAP1 in the nucleus and consequent cell proliferation and resistance to apoptosis; specific YAP1-MAML2 gene fusions are present in anaplastic thymomas lacking the GTF2I gene mutation, which is the most common mutation in A- and AB-type thymomas; YAP1-MAML2 fusions are present in sweat pore tumors and sweat pore carcinomas, and the YAP1-NUTM1 fusion is predominantly present in dermal ductal tumors, sweat gland sweat pore carcinomas, sweat pore carcinomas, head and neck sweat pore carcinomas, and sweat pore carcinomas with necrotic foci.