KRAS and pseudomyxoma peritonei: Recent studies of cytokeratin immunostaining patterns, clonality studies with LOH, and molecular studies of K-ras mutations have supported the conclusion that Pseudomyxoma peritonei usually takes origin from the appendix and not the ovary (Guerrieri et al, 1995, 1997; Cuatrecasas et al, 1996; Szych et al, 1999).