CNTN2 and mesenchymal cell neoplasm: This was the first demonstration that defines Tax as an oncoprotein in vivo. These data were later confirmed by the observation of an elevated expression of Tax in bone, associated with aberrant cell functions such as thymic atrophy [44], neurofibromatosis, muscle degeneration, lymphadenopathy, abnormal bone turnover [45] and mesenchymal tumors [25].