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Oncogenic human papillomavirus type distribution by L1 and E6/E7 sequencing

Abstract number: 1733_937

Perez S., Lopez I., Lamas M.J., Alvarez M.J., Vasallo F.J., Ulloa F., Torres J.

Objectives: A subgroup of human papillomavirus (HPV) termed ``high-risk'' is associated with more than 90% of cervical cancers. The aim of this study was to know the high-risk HPV distribution in women and its relationship with cytology in our environment.

Methods: 197 samples of endocervical scrapes (January to September, 2006) from 193 patients with recent cytological/histological data were selected. 3 PCRs per sample were carried out for the amplification of L1 and E6/E7 regions and the human b-globine gene, using consensus primers (MY09/MY11, HPCF/HPCR, HBBF/HBBR respectively). The PCR products of L1 and E6/E7 regions were analysed by sequencing using the same primers (Big Dye Terminator sequencing kit. Applied Biosystems. GenBank database).

Results: 2 samples (1%) were excluded because they were inhibited. HPV was detected in 59/195 samples (30.3%): 45/195 (23.1%) high-risk HPV, 2/195 (1%) low-risk HPV, 6/195 (3.1%) undetermined risk, 2/195 (1%) non-genotypable and 4/195 (2.1%) co-infections. The distribution of high risk genotypes according to cytological data was: normal cytology 17/140 (12.1%), atypical squamous cells of undetermined significance (ASC-US) 7/21 (33.3%), low grade squamous intraepithelial lesion (LSIL) 11/22 (50%), high grade squamous intraepithelial lesion (HSIL) 8/10 (80%), carcinoma 2/2 (100%). 20 of these 45 high-risk HPV (44.4%) were detected by only one of the two especific PCRs used.

50 patients were infected by only one HPV type: HPV 16: 17/50 (34%), HPV 31: 5/50 (10%), HPV 52: 3/50 (6%), HPV 56: 3/50 (6%), HPV 33: 3/50 (6%), HPV 66: 3/50 (6%), HPV 58: 2/50 (4%), HPV 82: 2/50 (4%), HPV 35, 39, 45, 53, 68: 1 of each type (2% each). It is important that certain genotypes undetected by commercial methods (HPV 53, 66, 82) were found in 12% of the patients. HPV 16 was the most frequent genotype detected in the patients with high-grade lesions (7/10 with HPV 16), however we have not found one predominant genotype in the patients with low-grade lesions (10/32 with HPV 16).

Conclusions: (1) PCR and DNA sequencing of part of L1 and E6/E7regions of HPV have a good sensitivity and diagnostic utility for the screening of uterine cervix cancer. (2) The amplification of both E6/E7 and L1 genes was necessary for the accurate detection and genotyping of HPVs. (3) HPV 16 was the most frequent genotype found in our population, followed by HPV 31. (4) HPV 16 represents most of the high-risk HPVs associated with HSIL and carcinoma.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Subject:
Location: ICC, Munich, Germany
Presentation type:
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