To the Editor We caution interpretation of data from the article by Tewari et al.1 They describe 6 groups of study participants (our numbering):

The authors state1 that no participants had detectable circulating tumor HPV DNA (ctHPVDNA). This in spite of 20 participants having DNA of an oncogenic HPV type detected in saliva, and 43 having serum antibodies to the HPVE6 oncogene.