However, recently, a recommendation for resection is considered appropriate only for MCNs with malignant features such as positive cytology for a malignant neoplasm; a mucinous cyst ≥ 3 cm; Kras and/or guanine nucleotide-binding protein (G protein); α stimulating activity polypeptide (GNAS) mutation with tumor protein 53 (TP53) and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit α (PIK3CA); or phosphatase and tensin homolog deleted from chromosome (PTEN) mutation by molecular testing [2, 4]. This evidence concerns the gene GNAS and cancer.