We have previously demonstrated that DU145 sphere cells possess a 100-fold higher capability of tumorigenesis [37] and are more resistant to a genotoxic reagent-induced cytotoxicity [39] in comparison to DU145 monolayer cells, further suggesting an association of MUC1 upregulation with chemoresistance in PC. The gene discussed is MUC1; the disease is pachyonychia congenita.