LAMP2 and cancer: Considering that the main role of LAMP2 as a glycoprotein is to protect the lysosome membrane against intra-lysosomal acidity42 and that we have observed localization of this protein at the cell membrane, we propose that this represents a new defence mechanism for acid adaptation in cancer cells: that the localization and overexpression of LAMP2 at the cell membrane makes acid-adapted cells resistant to damage by extracellular acidosis and probably acid-activated lysosomal hydrolases released into the ECM.