A Comparative Analysis of SOX2 Amplification in Squamous Cell Carcinomas of Lungs and Head and Neck.
Somak Roy, Carol Sherer, Kathleen Cieply, Sanja Dacic, Raja Seethala. UPMC, Pittsburgh, PA
Background: SOX2 (sex-determining region Y-box 2) has been recently identified as a major oncogene that is amplified and activated in squamous cell carcinoma (SCC). Several reports have indicated its role in early carcinogenesis of lung squamous cell carcinoma (LSCC). However, there is paucity of literature on SOX2 overexpression in head and neck squamous cell carcinomas (HNSCC). We have compared SOX2 expression in LSCC and HNSCC.
Design: 46 surgically resected, formalin fixed, paraffin embedded SCC (19 LSCC and 27 HNSCC) were randomly selected for SOX2 FISH analysis. Dual color FISH was performed using a Spectrum Green- labeled probe RP11-286G5 (3p24.3) (CHORI, Oakland, CA) and a Spectrum-Orange labeled, probe RP11-43F17 (3q26.3) (CHORI, Oakland, CA). At least 60 cells were scored for each case and control. A RP11-43F17 / RP11-286G5 signal ratio of 2.0 or greater was considered positive for SOX2 amplification. Results were then correlated with clinicopathologic parameters.
Results: LSCC more frequently showed SOX2 amplification (16/19, 84.2%) than HNSCC (10/27, 37%) (Fisher exact p = 0.002). While SOX2 non amplified LSCC had no disease related deaths, this difference in disease specific survival was not significant (log-rank p = 0.510). SOX2 amplification did not correlate with T stage or nodal status in LSCC. Although there was no statistically significant difference in frequency of SOX2 amplifiication between HNSCC with and without lymph node metastases, there was a trend towards more frequent SOX2 amplification in HNSCC with lymph node metastases. Specifically, SOX2 amplification was seen in 50% (6/12) node positive HNSCC patients, but not in node negative patients (p=0.1). Our results also suggest that frequency of SOX2 amplification of HNSCC may be influenced by anatomic location of the tumor. Of all HNSCC included in the study, oropharyngeal/hypopharyngeal tumors demonstrated the highest frequency of SOX2 amplification (5/9, 55%).
Conclusions: SOX2 amplification is a marker of squamous phenotype that is more frequently seen in LSCC than in HNSCC, though this cannot be used to distinguish site of origin. No significant outcome correlations were noted though there were small tendencies in both groups to have SOX2 amplification in more aggressive disease. The oropharynx/hypopharyngeal was the most commonly involved subsite in HNSCC.
Category: Head & Neck
Tuesday, March 1, 2011 1:00 PM
Poster Session IV # 141, Tuesday Afternoon