In the present study, we studied the activation mechanism of CADM1 expression in HTLV-1-infected T and ATLL cells and found that the down-regulation of p47 through lysosome/autophagy-dependent protein degradation plays an important role in the constitutive activation of the NF-κB pathway in ATLL cells, leading to the overexpression of CADM1. This evidence concerns the gene CADM1 and adult T-cell leukemia/lymphoma.