miRNAs in precancerous lesions of the gastrointestinal tract

Figure 1 miRNA analysis in formalin-fixed, paraffin-embedded samples. Routine histological analysis (hematoxylin and eosin) enables adequate selection of preneoplastic lesions (in this case, intestinal metaplasia and low-grade-intraepithelial neoplastic lesions obtained from a resected Barrett’s adenocarcinoma specimen). Either miRNA-specific in situ hybridization or immunohistochemical analysis of the miRNA gene targets could be performed starting from the original paraffin block. To obtain total RNA or DNA, lesions are macro-dissected from the paraffin block (or micro-dissected from unstained formalin-fixed, paraffin-embedded sections). The genome material can be further analyzed using modern genomic techniques. HE: Hematoxylin and eosin; FF-PE: Formalin-fixed, paraffin-embedded; IM: Intestinal metaplasia; LG-IEN: Low-grade-intraepithelial neoplastic lesions; ISH: in situ hybridization; IHC: Immunohistochemistry; qRT-PCR: Quantitative reverse transcription-polymerase chain reaction.