Prevalence of human papillomavirus type 16 and its variants in abnormal squamous cervical cells in Northeast Thailand.
OBJECTIVE
To investigate the prevalence of HPV, HPV16, and HPV16 variants in scraped cervical cells cytologically diagnosed as normal cervical cell and in formalin-fixed, paraffin-embedded tissues of cervical intraepithelial neoplasia II-III and squamous cervical carcinoma in Northeast Thailand.


METHODS
All samples were subjected to PCR using consensus GP5+/GP6+ primers. HPV16 was genotyped by Southern blot hybridization and reverse line blot hybridization. The HPV16 E6 gene was amplified and sequenced.


RESULTS
HPV infections were found in 33.8% of normal cervical cells, 97.3% of cervical intraepithelial neoplasia II-III, and 100% of squamous cervical carcinomas. The prevalence of HPV16 increased significantly with histological grade (normal cervical cell, 16.7%; cervical intraepithelial neoplasia II-III, 38.9%; squamous cervical carcinoma, 75%). The most common variant found was the Asian (As) (58.7%) followed by the European (E) lineage (41.3%). The HPV16 As lineages showed a risk association in 73.9% of squamous cervical cancer and 57.1% of cervical intraepithelial neoplasia II-III, while no increased risk was observed in the E lineages.


CONCLUSIONS
Our study demonstrates that HPV16, in particular the As variant, was the major causative agent associated with cervical cancer in Northeast Thailand, and our study suggests that some mutations of the E6 gene in this variant, which leads to amino acid changes, may be more carcinogenic.
Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
Peechanika
P
Chopjitt
Tipaya
T
Ekalaksananan
Chamsai
C
Pientong
Bunkerd
B
Kongyingyoes
Pilaiwan
P
Kleebkaow
Nicha
N
Charoensri
D001483:Base Sequence; D002294:Carcinoma, Squamous Cell / Q000453:epidemiology / Q000473:pathology / Q000821:virology; D002584:Cervix Uteri / Q000166:cytology / Q000821:virology; D004279:DNA, Viral / Q000032:analysis / Q000235:genetics; D005260:Female; D014644:Genetic Variation; D052162:Human papillomavirus 16 / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D006801:Humans; D008969:Molecular Sequence Data; D009856:Oncogene Proteins, Viral / Q000737:chemistry / Q000235:genetics; D030361:Papillomavirus Infections / Q000453:epidemiology / Q000473:pathology / Q000821:virology; D016133:Polymerase Chain Reaction; D015995:Prevalence; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics; D013785:Thailand / Q000453:epidemiology; D002583:Uterine Cervical Neoplasms / Q000453:epidemiology / Q000473:pathology / Q000821:virology; D014626:Vaginal Smears; D002578:Uterine Cervical Dysplasia / Q000453:epidemiology / Q000473:pathology / Q000821:virology
D004279:DNA, Viral; C068651:E6 protein, Human papillomavirus type 16; D009856:Oncogene Proteins, Viral; D012097:Repressor Proteins