Role of non-coding RNAs in pancreatic cancer: The bane of the microworld

Table 1 Types of non-coding RNAs in pancreatic cancer and their functions

Types	Name	Expression profile	Related biological function
Short ncRNAs
miRNAs	Let-7[117]	Up	Downregulates STAT3 phosphorylation
	miR-15/16[17,18]	Up	Promoting tumor angiogenesis
	miR-34a[29]	Down	Inactivates p53 and modulates pancreatic cancer pathogenesis
	miR-132[88]	Down	Transcribed by RNA polymerase II and promoter methylation
	miR-200[36]	Down	Leading to drug resistance
	miR-421[30,31]	Up	Suppresses expression of DPC4/Smad
piRNAs	pi-651[42]	Up?	piRNAs target transposon repression and DNA methylation
snoRNAs	U50, SNORD[46,118]	Up?
Long ncRNAs
lincRNAs	PPP3CB/MAP3K1 4/DAPK1 loci	Up	Metastases associated with the MAPK pathway[69]
	HOTAIR[73]	Up	Associates with the polycomb repressive complex 2
Other lncRNAs	HSATII (satellite repeat RNAs)[70]	Up	Reflect global alterations in heterochromatin silencing

HOTAIR: Homeobox transcript antisense RNA; MAPK: Mitogen-activated protein kinase; STAT3: Signal transducer and activator of transcription 3.