LRIG1 and hydrops fetalis: HF tumors in Lgr5 KI/R26R-tdTomato/Ctnnb1lox(ex3)/+ mutant skin arose in the absence of inflammation, while tumors initiated in the permanent portion of the epidermis of Lgr6 KI/R26R-tdTomato/Ctnnb1lox(ex3)/+ or Lrig1 KI/R26R-tdTomato/Ctnnb1lox(ex3)/+ mice were characterized by stromal inflammation (Arwert et al., 2012a, Hanahan and Weinberg, 2011).