• Kenjiro Date, Takao Ohtsuka, Takaaki Fujimoto, Koji Tamura, Hideyo Kimura, Taketo Matsunaga, Naoki Mochidome, Tetsuyuki Miyazaki, Yasuhisa Mori, Yoshinao Oda, Masafumi Nakamura, and Masao Tanaka.
• *Departments of Surgery and Oncology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan†Departments of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
• Ann. Surg. 2017 May 1; 265 (5): 969-977.

ObjectiveTo clarify clonality of distinct multisegmental main duct (MD)-intraductal papillary mucinous neoplasms (IPMNs) using microarray analysis.BackgroundIPMNs represent a pancreatic ductal cell field defect, which causes multiple occurrences of lesions. In addtion, it has been speculated that MD-IPMNs display features of monoclonal skip progression.MethodsTotal RNA was extracted from fresh-frozen tissue samples of metachronous MD-IPMNs and nonneoplastic pancreas tissue from the same pancreas from two individuals, and whole human genome microarray analysis was performed. Formalin-fixed paraffin-embedded tissue specimens from 28 distinct IPMNs were then collected from 12 patients, genomic DNA was extracted, and GNAS/KRAS mutational status was investigated. Immunohistochemical analysis was performed to validate the expression pattern of the indicated proteins.ResultsMicroarray analysis revealed that metachronous MD-IPMNs from the same individual displayed pair-wise correlation coefficients of 0.9523 and 0.9512. In contrast, MD-IPMNs of the same histological grade from different individuals displayed coefficients of 0.8092 and 0.8211. Scatter plot analysis revealed that metachronous MD-IPMNs from the same individual displayed a closer linear relationship. Furthermore, heat map and hierarchical cluster analyses revealed that metachronous MD-IPMNs from the same individual were classified in the same branch, and the gene expression patterns were similar. The GNAS/KRAS mutational statuses of distinct MD-IPMNs were consistent with each other. Immunohistochemical assessment of five specific proteins demonstrated that the same expression pattern between two lesions was observed in 95% of the samples.ConclusionsThese findings using molecular analyses indicate that MD-IPMNs might display features of monoclonal skip progression.

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