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during the pathogenesis of esophageal adenocarcinoma. They
could be markers for prediction of progression of Barrett’s esopha-
gus to esophageal adenocarcinoma [ 14 , 15 ]. MiRNAs such as
miR-221, miR-222, miR-196, and miR-21 are commonly deregu-
lated during the progression of esophageal adenocarcinoma [ 14 ].
Some of the possible pathways involved include modulating HOX
family, HMGA family, and annexin genes by miR-196 [ 16 ] and
increased cell proliferation via increased degradation of CDX2 by
miR-221/222 [ 17 ]. MiR-21 has been shown to be involved in
multiple downstream pathways including regulation of cell prolif-
eration and apoptosis via modulating a number of tumor- suppressor
genes such as tropomyosin-1 (TPM1), PTEN, maspin, and pro-
grammed cell death 4 (PDCD4) [ 18 ]. In addition, the role of vari-
ous miRNAs in metastasis of esophageal adenocarcinoma has been
studied [ 14 ]. MiR-145 expression has been linked to increased cell
adhesion to fibronectin, increased cell invasion, and resistance to
programmed cell death [ 19 ].
MiRNAs are important in treatment of esophageal cancers.
Several miRNA levels have been shown to correlate with treatment
response in patients with esophageal cancer [ 14 , 18 , 20 , 21 ]. MiR-
let- 7 can directly repress cisplatin-activated interleukin (IL)-6/
STAT3 pro-survival pathway and therefore modulate the chemo-
sensitivity to cisplatin [ 22 ]. MiR-296 can confer sensitivity of drugs
by attenuating the releasing amount of adriamycin through the
regulation of p-glycoprotein and regulation of Bcl-2 and Bax genes
[ 23 , 24 ]. Additionally, the uses of in vivo miRNA modulation
methods have been studied recently as novel therapeutic agents in
esophageal adenocarcinoma [ 25 , 26 ]. Furthermore, miRNA
expression levels have been shown to correlate with prognosis of
patients with esophageal adenocarcinoma [ 14 , 27 , 28 ]. For exam-
ple, miR-375 downregulation has been found to be significantly
correlating with poorer outcome of patients with esophageal ade-
nocarcinoma [ 14 ].
Thus, accurate detection and quantification of miRNA expres-
sion in tissues is important for management of patients with esoph-
ageal adenocarcinoma. The detection of miRNA is challenging as
miRNAs are short, exist in isoforms, and are highly similar to each
other [ 29 ]. Different techniques could be used to assess the
miRNA expression profile in tumor samples such as Northern blot
analysis [ 30 ], quantitative RT-PCR [ 31 ], and microarray hybrid-
ization [ 32 ]. This chapter describes the methodology of miRNAs
microarray and RT-qPCR for detection and quantification of miR-
NAs in esophageal adenocarcinoma (Fig. 1 ).Moein Amin et al.