The efficacy of PUVA has been studied in an in vitro model of cutaneous T-cell lymphoma (CTCL) cell lines (that have either functional p53 or inactive functional p53); in both cases, apoptosis occurred along with the upregulation of the mitochondrial genes BAK, BAX, and PUMA. This evidence concerns the gene BAX and primary cutaneous T-cell non-Hodgkin lymphoma.