The activation of α4β1 and CD44 bound gelatinase B/MMP-9 induces lyn/STAT/MCL-1 signalling and apoptosis in chronic lymphocytic leukemia cells, that depends upon gelatinase B/MMP-9 hemopexin and O-glycosylation domains [318,322] and in human medulloblastoma cells inhibition of gelatinase B/MMP-9 expression promotes apoptosis through β1 integrin and ERK activation [325]. The gene discussed is MMP9; the disease is B-cell chronic lymphocytic leukemia.