Expression of microRNA miR-205 in Pulmonary Squamous Cell Carcinoma and Adenocarcinoma
Krishan Kalra, Ling Xue, Elena E Chang, Raju Pillai, Mahul B Amin, Daniel J Luthringer. Cedars-Sinai Medical Center, LA, CA; BioGenex Laboratories, Fremont, CA
Background: Lung cancer represents a heterogeneous group of tumors comprised of mostly squamous cell carcinomas (SCC) and adenocarcinomas (AD). These tumors can be challenging to classify due to heterogeneity, sampling, and lack of differentiation. Targeted molecular therapies for lung cancer treatment require accurate classification for optimal response. MicroRNAs (miRNAs) are endogenous, non-coding RNAs with critical functions on gene regulation. microRNA expression profiles have great potential in tumor diagnosis and prognosis since they play essential roles in tissue differentiation during normal development and oncogenesis. miR-205 has been shown to regulate E-cadherin and possibly target PTEN, and thus have role in tumor supressor function. The purpose of this study is to explore the utility of miR-205 expression in distinguishing SCC and AD.
Design: Samples of 10 formalin-fixed paraffin-embedded lung cancers (5 AD; 5 SCC) were classified using H&E staining and confirmed by IHC using anti-TTF1 (BioGenex, BGX397A) and anti-p63 (BioGenex, AM418) antibodies. 5 normal lung samples served as controls. FAM-labeled miR-205 (BioGenex, HM205) and One-step ISH Detection Kit (BioGenex, DF400) were used in this study. Slides were heated in Nucleic Acid Retrieval Solution I (NAR-I, BioGenex) for 10 min at 92C, subjected to hybridization buffer for 30 min, incubated with 40 nM of microRNA probe for 60 min at 50 C followed by stringency washes. The signal was amplified with anti-fluorescein antibody and poly-HRP labeled secondary antibody, which can develop brown color with DAB chromogen. Scramble probes served as negative control. The staining results were independently reviewed by pathologists to render diagnostic impression.
Results: Using miRNA in situ hybridization system, we found that miR-205 was up-regulated in 4/5 (80%) of lung SCC and 2/5 (40%) of AD. Scramble (negative controls) probes were non-reactive.
Conclusions: This result suggests miR-205 may have the potential to differentiate SCC from AD. Additional studies are in progress to determine the utility of miR-205 expression in differentiating sub-types of lung cancer. Importantly, microRNAs may be utilized as a diagnostic tool in lung cancer classification.
Wednesday, March 6, 2013 1:00 PM
Poster Session VI # 296, Wednesday Afternoon