CYLD and neoplasm: Our data suggesting the role of CYLD as a tumor suppressor of skin squamous cell tumors in vivo are in agreement with those of Cyld-/- mice, in which other authors found that mice lacking the Cyld gene exhibited increased susceptibility to skin cancer development in chemical carcinogenesis experiments [32]; they also agree with our recent results showing that transgenic mice lacking the deubiquitinase function of CYLD in keratinocytes, K5-CYLDC/S mice, spontaneously develop skin tumors [11].