To explore the potential of tumor-specific DNA as a biomarker for head and neck squamous cell carcinomas (HNSCC), we queried DNA from saliva or plasma of 93 HNSCC patients. We searched for somatic mutations or human papillomavirus genes, collectively referred to as tumor DNA. When both plasma and saliva were tested, tumor DNA was detected in 96% of 47 patients. The fractions of patients with detectable tumor DNA in early- and late-stage disease were 100% (n = 10) and 95% (n = 37), respectively. When segregated by site, tumor DNA was detected in 100% (n = 15), 91% (n = 22), 100% (n = 7), and 100% (n = 3) of patients with tumors of the oral cavity, oropharynx, larynx, and hypopharynx, respectively. In saliva, tumor DNA was found in 100% of patients with oral cavity cancers and in 47 to 70% of patients with cancers of the other sites. In plasma, tumor DNA was found in 80% of patients with oral cavity cancers, and in 86 to 100% of patients with cancers of the other sites. Thus, saliva is preferentially enriched for tumor DNA from the oral cavity, whereas plasma is preferentially enriched for tumor DNA from the other sites. Tumor DNA in saliva was found postsurgically in three patients before clinical diagnosis of recurrence, but in none of the five patients without recurrence. Tumor DNA in the saliva and plasma appears to be a potentially valuable biomarker for detection of HNSCC.

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BACKGROUND Human papillomavirus (HPV) is a well-established prognostic marker for oropharyngeal squamous cell cancer (OPSCC). Because of the limited numbers of women and nonwhites in studies to date, sex and racial/ethnic differences in prognosis have not been well explored. In this study, survival differences were explored by the tumor HPV status among 1) patients with OPSCCs by sex and race and 2) patients with nonoropharyngeal (non-OP) head and neck squamous cell cancers (HNSCCs). METHODS This retrospective, multi-institution study included OPSCCs and non-OP HNSCCs of the oral cavity, larynx, and nasopharynx diagnosed from 1995 to 2012. Race/ethnicity was categorized as white non-Hispanic, black non-Hispanic, Asian non-Hispanic, and Hispanic of any race. Tumors were centrally tested for p16 overexpression and the presence of HPV by HPV16 DNA and high-risk HPV E6/E7 messenger RNA in situ hybridization. Kaplan-Meier and Cox proportional hazards models were used to evaluate overall survival (OS). RESULTS The study population included 239 patients with OPSCC and 621 patients with non-OP HNSCC with a median follow-up time of 3.5 years. After adjustments for the tumor HPV status, age, current tobacco use, and stage, the risk of death was lower for women versus men with OPSCC (adjusted hazard ratio, 0.55; P =.04). The results were similar with p16. In contrast, for non-OP HNSCCs, HPV positivity, p16 positivity, and sex were not associated with OS. CONCLUSIONS For OPSCC, there are differences in survival by sex, even after the tumor HPV status has been taken into account. For non-OP HNSCC, the HPV status and the p16 status are not of prognostic significance.