microRNA-196A: A Potential Marker of Progression in Barrett's Esophagus-Dysplasia-Adenocarcinoma Sequence
DM Maru, RR Singh, C Hannah, CT Albarracin, A Romans, YX Li, R Abrahams, H Yao, MG Luthra, SG Swisher, WL Hofstetter, AR Rashid, R Luthra. The University of Texas MD Anderson Cancer Center, Houston
Background: The low yield and high cost of endoscopic screening for Barrett's esophagus (BE) necessitates a need for novel biomarkers like microRNA (miR) in progression of BE. We recently showed high miR-196a in esophageal adenocarcinoma (EA). In this study we evaluated miR-196a as a marker of progression in BE-dysplasia-EA sequence and correlated miR-196a with it's in silico predicted targets in EA.
Design: miR-196a levels were measured in microdissected samples of normal squamous (NSM), BE (intestinal metaplasia), low-grade dysplasia (LGD) and high-grade dysplasia (HGD) from formalin fixed tissue of surgically resected specimens of 10 stage I EA patients, by stem loop real-time qPCR using TaqMan minor groove binding probe (Applied Biosystems, CA). miR-196a levels were measured from EA in 5 of 10 patients. miR-16 was used as a normalizer and miR-196a expression was measured by comparative CT method (2-CT). Next, we correlated miR-196a with mRNA levels of its targets; keratin 5 (KRT5), small proline-rich protein 2C (SPRR2C), S100 calcium binding protein A9 (S100A9), that are downregulated during progression of BE, in frozen samples of additional 10 patients of EA. For cDNA synthesis 200 ng of RNA was reverse transcribed and real time qPCR was performed with TaqMan minor groove binding probe and ABI Prism7900 HT sequence detection system (PE Applied Biosystems). Statistical analysis was performed using SPSS(SPSS, IL).
Results: The population for progression analysis had 10 men (age:65 yrs). The mean (M)SD miR-196a levels were 0.00050.0007 in NSM, 0.01400.015 in BE, 0.0130.009 in LGD, 0.0300.016 in HGD and 0.07900.058 in EA. The differences among each stage were statistically significant by one-way within subjects ANOVA with p < 0.0001. The pair wise comparison for miR-196a levels in each lesion was significantly higher than control NSM: NSM vs. BE (p=0.00001) vs. LGD (p=0.001), vs. HGD (p=0.0006) vs. EA (p=0.00005). The population for target correlative study included 9 men and 1 woman (age:62 yrs) and stage II or III disease. The MSD miR-196a level in EA (0.0250.009) was higher than NSM (0.000470.00067). The MSD mRNA levels of SPRR2C, S100A9 and KRT 5 were 23.4638.36, 246.4359.3, 2936.87 and correlated inversely with miR-196a levels (p<0.01).
Conclusions: miR-196a is a potential marker of progression of BE-dysplasia-EA sequence and KRT5, SPRR2C and S100A9 are targets of miR-196a in EA.
Tuesday, March 10, 2009 1:00 PM
Poster Session IV # 111, Tuesday Afternoon