Human papillomavirus type 16 E2 and E6/E7 variants

Objectives. Polymorphisms in human papillomavirus (HPV) type 16 have been shown to be related to geographic areas and are broadly classified as European (E), African (At), Asian (As), or Asian-American (AA). Certain variants have been reported as being more likely to cause cervical disease; our objectives were to identify new HPV16 polymorphisms, to determine the linkage of the E2 and E6/E7 regions and to determine the minimum sequence necessary to classify variants. Methods. We sequenced the complete E2, E6, and E7 regions in all HPV16-positive cervical samples identified in a case-control study of pre-invasive cervical disease. Results. In the 100 samples analyzed, only one new polymorphism was identified, a synonymous change, T3205A, in region E2. The frequency distribution of variants in the sample set was 37 European prototypes and 27 E-G350, 16 AA, 5 Af1, 2 Af2, 8 E-C109G, 3 E-G131G, and 2 As. As shown by others, region E7 varied much less than E6 and E2. Conclusions. In each case, E2 changes were linked to the expected E6/E7 changes, and there was no evidence for recombination. The linkage between E2 and E6/E7 allows variant classification to be based on a short E6 sequence (nt 109-350). (c) 2004 Elsevier Inc. All rights reserved.