MicroRNAs in Pancreatic Cancer: Involvement in Carcinogenesis and Potential Use for Diagnosis and Prognosis

Table 4

Types of samples used for miRNA analysis in pancreatic cancer.

	Serum	Fine needle biopsy	Resected tissue
Invasiveness	Low	Medium	High
Possible sampling frequency	Days	Days-weeks	Mostly no or only one sampling
The amount of sample/target miRNA	Sufficient/very small	Small/small	Sufficient/sufficient
The possibility of obtaining pure tumor tissue (cells)	No	Yes (microdissection)	Yes (macrodissection, microdissection)
Respective references	[54, 58, 68, 84–86]	Fixation [62, 67, 89]; RNA stabilization solution [67, 74]	Frozen tissue [53, 56, 61, 63, 70, 72, 76, 97]; Fixation [59, 67, 78, 84, 90, 96]