When MDA-MB-231 or RWGT2 tumor cells were grown on rigid substrates (1.7 and 67 GPa) with moduli bracketing that of mineralized bone matrix (18.4 GPa) [35], both Gli2 and PTHrP expression were 2–4 times higher compared to soft PAA gels (0.45 kPa). Here, GLI2 is linked to neoplasm.