Global DNA methylation patterns in small intestinal neuroendocrine tumors (SI-NETs)

• Small intestinal neuroendocrine tumors (SI-NETs) are rare hormone producing tumors and are often diagnosed at advanced stage. The genetic and epigenetic background of SI-NETs are poorly understood, but several reports have indicated chromosomal losses at 18.21-qter and 11q22-q23. The aim of this study was to characterize CpG DNA methylation status of primary SI-NETs and the corresponding lymph node metastases. We used the commercially available HumanMethylation27 Beadchip array (Illumina), which covers 27578 CpG sites spanning over 14495 genes, and analyzed a discovery cohort of 10 primary SI-NETs with matched metastases. Messenger- mRNA, were determined for selected genes in a 47 tumors. In comparison to the primary tumors, the metastases showed 2697 statistically significant differentially genes. Metastases were generally less methylated than primary tumors. The relative mRNA expression level of the differentially methylated genes AXL, CRMP1, FGF5, and APOBEC3C largely reflected the methylation status. MAPK4, RUNX3, TP73, CCND1, CHFR, AHRR, and Rb1 known to be hypermethylated in other cancer types, displayed overall high methylation level (β-value ≥ 0.9). Methylation (β -value >0,7) at 18q21-qter and 11q22-q23 were detected in genes SETBP1, ELAC1, MBD1, MAPK4, TCEB3C and ARVC1, MMP8, BTG4, APOA1, FAM89B, HSPB1, respectively. Furthermore unsupervised clustering of the tumors identified three distinct clusters, one with a highly malignant behavior. Our data supports involvement of CpG DNA methylation in metastatic progression of SI-NETs and this could present a possibility to identify more aggressive tumors based on DNA methylation.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Kirurgi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Surgery (hsv//eng)

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)