MMP2 and melanoma: Moreover, the intratumor production of the transcription factor AP-1 (c-Jun subunit) that regulates the expression of MMP-2 [21] as well as the levels of HIF-1 (α subunit, HIF-1α), that are tightly linked to the aggressive phenotype of melanoma cells [22], were determined via Western blot (Figure 6A–D).