Low elasticity score at elastosonography in thyroid nodule is correlated with malignancy,degree of fibrosis, high expression of Galectin-3 and Fibronectin-1

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: MON 471-496-Thyroid Neoplasia & Case Reports
Monday, June 17, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board MON-473
Paolo Vitti1, Teresa Rago*2, Maria Scutari1, Valeria Loiacono3, Liborio Torregrossa4, Riccardo Giannini3, Nicla Borrelli3, Agnese Proietti3 and Fulvio Basolo2
1University of Pisa, Italy, 2University of Pisa, Pisa, Italy, 3university of pisa, Pisa, Italy, 4university of pisa, pisa, Italy
Introduction: Ultrasound elastography (USE) provides an estimation of tissue stiffness and has been already applied to differentiate malignant from benign lesions in several tissues. Galectin-3 (Gal-3) and Fibronectin-1 (FN-1) are involved in multiple functions, including cell-cell and cell-matrix adhesion, tissue fibrosis, and tumor progression.

Methods: This study included 78 consecutive patients with a single thyroid solid nodule who underwent surgery for a cytology result of indeterminate (n=39) or indicative /suspicious of malignancy (n= 39) at fine needle aspiration. USE was performed using a real-time instrument (Hitachi, Logos EUB 8500 with a 10 MHz linear transducer). Tissue stiffness was scored from 1 (high elasticity) to 2-3 (low elasticity). Gal-3 and FN-1 mRNA quantification was performed using the two-step Real-Time Quantitative RT-PCR Rotor Gene Sybr Green PCR Kit (Qiagen) on a Rotor Gene 6000 (Qiagen) instrument. Beta-Actin mRNA was used as an internal control. Pooled normal thyroid tissue was used as external control. The comparative threshold cycle (Ct) method, defined as 2-ΔΔCt, were used for the calculation of fold amplification of each sample versus external control.

Gal-3 and FN-1 mRNA expression was normalized, positive and negative z scores indicating a value above or below the mean, respectively. The converted z scores were then aggregated into one large set, identifying two different categories: ‘low expression’ (negative z score), ‘high expression’ (positive z score). Tumor fibrosis, evaluated using haematoxylin and eosin staining by both optical and digital microscope analysis, was scored as the percentage of fibrosis with respect to tumor cell-occupied area.

Results: Score 1 at USE was found in 33 cases, 32 benign lesions and 1 carcinoma at histology; score 2-3 in 45 cases, all carcinomas. The low elasticity was highly predictive of malignancy (p<0,0001).

High expression of Gal-3 was found in 33/45 nodules with score 2-3 at USE and only in 2/32 nodules with score 1 (p<0.0001). High expression of FN-1 was found in 26/45 nodules with score 2-3 at USE and in none with score 1 (p<0.0001). The degree of fibrosis was 10,46% + 17,15 in nodules with score 1 and 22,5% + 25,73 in those with score 2-3 (p=0,025).

In conclusion these data: i) confirm that low elasticity at USE is highly correlated with malignancy; ii) suggest that low elasticity is linked with fibrosis and higher expression of Gal-3, FN-1, involved in tumor progression.

Real-time elastosonography: useful tool for refining the presurgical diagnosis in thyroid nodules with indeterminate or nondiagnostic cytology.Rago T, Scutari M, Santini F, Loiacono V, Piaggi P, Di Coscio G, Basolo F, Berti P, Pinchera A, Vitti P.J Clin Endocrinol Metab. 2010 Dec;95(12):5274-80Elastography: new developments in ultrasound for predicting malignancy in thyroid nodules.Rago T, Santini F, Scutari M, Pinchera A, Vitti P.J Clin Endocrinol Metab. 2007 Aug;92(8):2917-22

Disclosure: PV: Coinvestigator, Bracco S.p.A.. Nothing to Disclose: TR, MS, VL, LT, RG, NB, AP, FB

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm