Differential expression of EGFR, HER2, P16, and high-risk (hr) HPV status in oropharyngeal (Or) and oral cavity (OC) squamous cell carcinoma (SCC).

Abstract

5521 Background: We aimed to better characterize the expression of epidermal growth factor receptors family in Or and OC SCC and correlate it to hr HPV status and anatomoclinical features. Methods: In formalin fixed paraffin embedded tumor tissues, chromogenic in situ hybridization (CISH) was performed to detect hr HPV and immunohistochemistry to evaluate EGFR (positive score: 4 to 6), HER2 (0=negative, 1=positive) and P16 (positive score:≥70% labeled cells) expression. Baseline data were collected and analyze will be used. Results: Among 128 pts, 69 were tobacco users and 58 male. Median age at diagnosis was 61 y [23-95]. EGFR, Her2, P16 expression and hrHPV positivity were seen in 84 (65%), 12 (9%), 47 (37%) and 47 (37%) respectively. P16 signal was linked with absence of tobacco (31% vs. 72%, Pearson chi2 test: p<10-3), absence of alcohol (48% vs. 83%, p<10-3), Or site (53% vs. 76%, p=0.005), T1 (34% vs. 19%, p=0.06), N0 (52% vs. 23%, p=0.003), absence of nodal capsular rupture (85% vs. 68%, p=0.02), WHO grade 3 (37% vs. 68%, p=0.001), hr HPV detection (17% vs. 70%, p<10-3). Multivariate analysis confirmed the link between P16 expression and hr HPV CISH positivity (OR=0.05, CI 95% [0.01-0.21], p<10-3) , absence of tobacco (OR=9.2, CI 95% [2.1-40.7], p=0.03) and N0 (OR=0.2, CI 95% [0.04- 0.75], p=0.02). EGFR signal was linked with tobacco (31% vs 78%,p=10-3), alcohol (57% vs 81%, p=0.02), OC localization (77% vs 58%, p=0.03), well differentiated SCC (73% WHO grade 1-2 vs 56% grade 3, p=0.04), absence of hr HPV detection (74% vs 52%, p=0.01) and absence of P16 labeling (78% vs 44%, p<10-3). Multivariate analysis confirmed the link between EGFR positivity and tobacco (OR=0.32, CI 95% [0.1-0.9], p=0.03), alcohol (OR=9.5, CI 95% [1.2- 72.8], p=0.03) and OC localization (OR=0.3, CI 95% [0.1-1], p=0.05). HER2 signal was linked with alcohol (5% vs 18%, p=0.04), history of tobacco associated neoplasia (10% vs 0%, p=0.02), Or site (14% vs 2%, p=0.03) and who grade 3 (5% vs 14%, p=0.06). Her2 labeling was not associated with tobacco, sex, hr HPV detection, P16 positivity or EGFR one. Conclusions: Hr HPV associated SCC have a low expression of EGFR and are not associated with HER2 labeling.