Intriguingly, two studies found that H3K4 trimethyltransferase complex was recruited on the MMP9 promoter in T-cell lymphoma cells, and knockdown of MLL showed reduced MMP2 and MMP9 in melanoma cells [35, 36], which enabled us to suspect that reduced MLL and H3K4 trimethylation was responsible for low expression of MMP2 in cell lines with MLL translocation. This evidence concerns the gene MMP2 and melanoma.