TCF4 and cancer: To assess whether the upregulation of Hspb1 is a direct result of Wnt/β‐catenin pathway activation, we used a β‐catenin mutant cancer cell line carrying a construct containing an inducible dominant negative TCF4 (dnTCF4), which upon doxycycline administration acts as inhibitor of the Wnt pathway (Fig 2A; Van de Wetering et al, 2002).