SP1 and melanoma: Moreover, Tripathi et al. investigated the signaling pathways leading to increased cathepsin secretion in melanoma cells and found that the nonreceptor tyrosine kinases Abl and Arg induced the secretion of cathepsins B and L by activating transcription factors, including Ets1, Sp1, and NF-κB/p65, which play critical roles in driving melanoma invasion and metastasis [40].