MMP14 and cancer: In this regard, minocycline, a highly lipophilic microglia inhibitor with an excellent BBB penetration property, has recently been proven to be a promising novel candidate for adjuvant therapy against malignant GBM since it reduced GBM growth both in vitro and in vivo, by an attenuation in the expression of protumorigenic effects of MT1-MMP as well as a significant inhibition in p38 MAPK expression (responsible for MT1-MMP upregulation in microglia) [108].