Targeted sequencing reveals TP53 as a potential diagnostic biomarker in the post-treatment surveillance of head and neck cancer

// Joost H. van Ginkel 1, 2 , Wendy W.J. de Leng 2 , Remco de Bree 3 , Robert J.J. van Es 1, 3 , Stefan M. Willems 2 1 Department of Oral and Maxillofacial Surgery, University Medical Center Utrecht, Utrecht, The Netherlands 2 Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands 3 Department of Head and Neck Surgical Oncology, University Medical Center Utrecht, Utrecht, The Netherlands Correspondence to: Stefan M. Willems, email: s.m.willems-4@umcutrecht.nl Keywords : head and neck cancer, mutations, next-generation sequencing, TP53 , diagnostic biomarkers Received: May 20, 2016      Accepted: July 28, 2016      Published: August 11, 2016 ABSTRACT Head and neck squamous cell carcinomas (HNSCC) form a large heterogeneous group of tumors and have a relatively poor outcome in advanced cases. Revealing the underlying genetic mutations in HNSCC facilitates the development of diagnostic biomarkers, which might lead to improved diagnosis and post treatment surveillance. We retrospectively analyzed mutational hotspots using targeted next-generation sequencing (NGS) of 239 HNSCC tumor samples in order to examine the mutational profile of HNSCC. Furthermore, we assessed prevalence, co-occurrence, and synonymy of gene mutations in (matched) tumor samples. TP53 was found mutated the most frequent with mutation rates of up to 83% in all tumors, compared to mutation rates of between 0 and 21% of CDKN2A , PIK3CA , HRAS , CDK4 , FBXW7 and RB1 . Mutational co-occurrence predominantly existed between TP53 and PIK3CA , TP53 and CDKN2A , and HRAS and PIK3CA . Mutational synonymy between primary tumor and associated metastasis and recurrence was present in respectively 88% and 89%. TP53 mutations were concordantly mutated in 95% of metastases and in 91% of recurrences. This indicates TP53 mutations to be highly prevalent and concordant in primary tumors and associated locoregional metastases and recurrences. In turn, this provides ground for further investigating the use of TP53 mutations as diagnostic biomarkers in HNSCC patients.