Abstract 2700: Specific cell populations from the primary tumor invasive front and lymph nodes show protein signatures associated with local metastasis in head and neck cancer

Abstract

Abstract Lymph node metastasis is the main prognostic factor in patients with head and neck squamous cell carcinoma (HNSCC), but no molecular markers are currently used in clinical practice. Considering that the invasive front (IF) of the tumor has a prognostic value due to the invasive and metastatic potential of the cells, we explored the mechanisms associated with lymph node metastasis in the primary tumor IF and its paired lymph nodes from HNSCC patients. For that, the proteomic profile was determined for formalin-fixed, paraffin-embedded (FFPE) tissues using mass spectrometry in a 29-patient cohort. Specific cell populations from primary tumor IF (tumor and stroma cells) and lymph nodes (microenvironment cells) were microdissected and HPV genotyping was performed. In total, 27.5% of the cases were positive for HPV16 and 2,154 ± 285 proteins were identified for the three cell populations analyzed. Eighty-one proteins from tumor cells, 36 proteins of stroma cells and 149 proteins of lymph node microenvironment cells were differentially expressed between HNSCC patients positive and negative for lymph node metastasis (Student´s t-test; P-value ≤ 0.05). Specific processes were enriched for the differentially expressed proteins from tumor, stroma and lymph node cells, including post-translational modification, splicing and translation, respectively. Interestingly, differential proteins isolated from primary tumor cells are mainly transported by exosomes. Therefore, our data provide protein signatures related to lymph node metastasis that are expressed by specific cell populations and candidates as prognostic markers in HNSCC. Financial support: FAPESP (Process number 2015/19191-6). Citation Format: Ariane F. Busso-Lopes, César Rivera, Carolina C. Macedo, Barbara P. Mello, Luisa L. Villa, Wilfredo A. González-Arriagada, Adriana F. Paes Leme. Specific cell populations from the primary tumor invasive front and lymph nodes show protein signatures associated with local metastasis in head and neck cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2700.