CD44 and cancer: Since glioblastoma CSCs express podoplanin [180,181], CD44 is present in SCCs [33], and podoplanin binds both CD44 [33] and MMP14 [211] at the surface of cancer cells, it should be of great interest to explore the role of the podoplanin–CD44 interaction in invadopodia assembly and maturation, and the recruitment of MMP14 to these membrane structures.