Quantitative RT-PCR analysis of MMR genes on EUS-guided FNA samples from focal pancreatic lesions.

ABSTRACT

BACKGROUND/AIMS: Pancreatic cancer is characterized by a variety of molecular alterations. Mismatch excision repair (MMR) is a DNA repair system that eliminates mismatched base pairs and it plays an important role in the maintaining of genomic integrity. The aim of the study was to assess the role of several MMR genes in the diagnosis of pancreatic cancer in samples collected by EUS-FNA procedure. METHODOLOGY: The prospective study included 44 consecutive patients with pancreatic cancer (n=24) and chronic pseudotumoral pancreatitis (n=20). EUS-FNA was performed in all the patients. Gene analysis was performed by extracting the mRNA and by determining the expression of DNA repair genes (MLH1, MLH3, MSH6) using a standard algorithm. RESULTS: Total RNA was successfully isolated from all the EUS-FNA pancreatic samples. We analyzed ROC curves to assess the significance of determining the expression of analyzed genes in EUS-FNA samples, obtaining a cutoff value of 476621mRNA copies/mL for MSH6, and sensitivity and specificity of 75.0% and 100%, respectively. For MLH1 and MLH3, sensitivity and specificity were only satisfactory (64.65% and 76.11%, and 75.0% and 63.64%, respectively). CONCLUSIONS: The quality and amount of cellular sampling using pancreatic EUS-FNA allow the extraction of sufficient quantities of RNA to perform qRT-PCR analysis. The use of MMR genes for the differentiation between pseudotumoral chronic pancreatitis and pancreatic cancer using a minimally invasive sampling technique could be a promising technique.