In a prospective study enrolling 36 lesions (28 classified as mucinous and 6 as non-mucinous), all exons of the following genes were included and sequenced from the cyst fluid by targeted Next-Generation Sequencing (tNGS): AKT1, ALK, APC, BRAF, CDKN2A, CDH1, CTNNB1, DDR2, EGFR, ERBB2, ESR1, FBXW7, FGFR1, FGFR2, FGFR3, FOXL2, GNA11, GNAQ, GNAS, HRAS, IDH1, IDH2, KIT, KRAS, MAP2K1, MET, NOTCH1, NRAS, PDGFRA, PIK3CA, PIK3R1, PTEN, RET, RNF43, ROS1, SMAD4, TGFBR2, TP53 and VHL. Here, SMAD4 is linked to cyst.