Cuatrecasas M et al (1997) found that the frequency of Kras mutations in codons 12 and 13 was lower in benign (58.33%, n = 35/60) than in borderline (86.36%, n = 19/22) or malignant mucinous ovarian tumors (84.61%, n = 11/13) by polymerase chain reaction (PCR) and restriction fragment length polymorphisms (RFLP). The gene discussed is KRAS; the disease is ovarian mucinous neoplasm.