LTA and Merkel cell skin cancer: Although inhibition of SCFFbw7 stabilizes MCV LT, introduction of mutations in the sT LT-stabilization domain decreases LT protein levels and eliminates synergism in MCV DNA replication and sT-induced cell transformation.92 MCV sT is detected in 92% of MCC tissues, whereas MCV LT is only detected in 75% of the tissues.87,89,93 However, the full function of MCV sT in MCC cells requires other T antigens, such as LT and 57kT.85,94