KRAS and pachyonychia congenita: In a large patient-control study involving 201 patients with PC or benign pancreatic disease (BPD) and 60 healthy controls, stool and pancreatic juice were screened for KRAS and TP53 mutations using PCR-restriction fragment length polymorphism (PCR-RFLP) and PCR-single-strand conformation polymorphism (PCR-SSCP) analyses.