Human papillomavirus (HPV) type 16 and 33 E6/E7 region transcripts in tonsillar carcinomas can originate from integrated and episomal HPV DNA. - Snijders,P.J.; Meijer,C.J.; van den Brule,A.J.; Schrijnemakers,H.F.; Snow,G.B.; Walboomers,J.M. (J Gen Virol, 1992)