Gene-expression profiles of primary and metastatic lesions in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is a heterogeneous group of malignancies arising from different sites and the 8th most common type of cancer in the world. While the advent of new techniques and multimodality therapy have improved prognosis of locally HNSCC, the appearance of distant metastases (DM) remains a challenge both for prognosis and treatment. To date, the genomic landscape of dissemination of HNSCC has to be further studied, in order to predict whether a patient will develop distant metastases. Therefore, knowing that the risk of disease spread to DM is directly correlated to initial staging, it suggested the hypothesis that the development of DM could be linked to the biologic characteristics of the primary tumor. The aim of our work is to compare gene expression profile of primary tumors of patients who develop and not develop DM. Additionally, we studied the expression profile of matched distant metastasis. We identified and matched histologically confirmed primary tumor of 49 HNSCC patients, divided in 24 without metastasis (“T-without”) and 25 with distant metastasis (“T-with”), collected from 2006 to 2016. In 23 of the 25 selected T-with cases, we collected matched FFPE samples of the distant metastasis (M). The following criteria have been used to match T-with versus T-without based on clinical and radiological staging: i) cT1 has been matched with cT1 or cT2 and viceversa for staged cT2 tumors; ii) cT3 has been matched with cT3 or cT4 and viceversa for cT4; iii) cN1 has been matched with cN0 or cN1; cN2 has been matched with cN3 and viceversa for cN3. T-with and T-without were well balanced per age, sex and previous radiotherapy performed in the curative setting on the head and neck area. Among T-with patients, the majority had lung metachronous metastases.