TIMP1 and glioma: Furthermore, glioma Δ9-THC treatment can downregulate TIMP-1 and MMP-2, showing that these effects were mediated via ceramide accumulation and activation of p8 stress protein and, interestingly, it was observed in glioma-bearing mice as well as in two patients with recurrent GBM who had received intra-tumor injections with Δ9-THC [123].