CDKN2A and neoplasm: Using targeted analysis of only a few genes (TP53, PIK3CA, CDKN2A, NOTCH1), the authors were able to establish the tumor “fingerprint” and later track the corresponding mutations of cfDNA in the blood and saliva of 63 HPV-negative HNSCC patients.77 Tumor-derived cfDNA was detected in all patients with OSCC (80% of plasma samples and 100% of saliva samples).77 Interestingly, cfDNA was detected as early as 19 months before recurrence in the saliva and plasma from one surgically treated patient, providing a proof of principle that sensitive and specific detection of cfDNA is possible in OSCC.77