miR-205 and miR-21 Quantification in Adenocarcinomas and Squamous Cell Carcinoma of the Lung.
Valerio Del Vescovo, Chiara Cantaloni, Alberto Cucino, Salvatore Girlando, Massimo Silvestri, Emma Bragantini, Luca Morelli, Silvia Fasanella, Lucia V Cuorvo, Paolo Dalla Palma, Giulio Rossi, Mauro Papotti, Giuseppe Pelosi, Paolo Graziano, Alberto Cavazza, Michela A Denti, Mattia Barbareschi. University of Trento, Italy; S.Chiara Hospital, Trento, Italy; S. Chiara Hospital, Trento, Italy; Azienda Ospedaliera-Universitaria Policlinico, Modena, Italy; San Luigi Hospital and University of Turin, Orbassano, Italy; Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; Forlanini Hospital, Rome, Italy; Arcispedale S. Maria Nuova, Reggio Emilia, Italy
Background: Classification of non-small cell lung cancers is of paramount clinical relevance, as novel chemotherapeutic agents show different efficacy in adenocarcinomas (ADC) as compared to squamous cell carcinomas (SQCC). The measurement of miR-205 and miR-21 may be an additional tool for the distinction between ADC and SQCC. Aim of our study is to compare morphological and immunohistochemical classification with miR-205 and miR-21 relative quantification in surgically resected and well characterized lung tumors.
Design: A series of 50 consecutive lung carcinomas (25 ADC, 24 SQCC, 1 adenosquamous) have been histologically confirmed and immunostained for TTF1, p63, p40, desmocollin 3, napsin A, CK5, CK7. Quantification of microRNA expression was carried out using TaqMan MicroRNA Assay kits according to manufacturer's protocol (Applied Biosystems, USA). Real-time RT-PCR assay is based on a stem-loop RT primer design. U6snRNA is a widely used endogenous reference RNA in microRNA quantification experiment. Normalized Ct of miR-205 and miR-21 was calculated according to Lebanony et al. (J Clin Oncol. 2009;27:2030-2037.).
Results: miR-21 relative levels are similar in SQCC and ADC, while miR-205 relative levels are lower in ADC (p<0.0001). The miR-205 sample score value is higher in ADC compared to SQCC; accordingly 22 tumors can be classified as ADC and 28 as SQCC, although 8 cases (2 SQCC and 6 ADC) are in the range of “near cut-off values”. 4 cases classified as SQCC according to the sample score method corresponded to cases classified as ADC on the basis of morpho-immunohistochemical evaluation.
Conclusions: miR-205/miR-21 relative quantification seems a promising diagnostic tool. However the molecular approach is still not completely satisfactory as it may misclassify a non negligible percentage of cases, but it could be used as an adjunctive diagnostic criterion in selected cases.
Tuesday, March 1, 2011 1:00 PM
Poster Session IV # 247, Tuesday Afternoon