Pap test, HPV test, and histological diagnosis of cervical disease
All patients underwent Pap tests and HPV tests using liquid-based cytology samples. Scraped cell samples were collected with a Cervex-Brush (Rovers Medical Devices, Oss, Noord-Brabant, The Netherlands) and placed in liquid-based cytology solution. Sample collection was performed by an experienced obstetrician or gynecologist. Pap tests were performed according to the Bethesda system by cytotechnologists, and the results were verified by pathologists.
Abnormal Pap test results included atypical squamous cells of undetermined significance (ASCUS), atypical squamous cells not excluding high-grade squamous intraepithelial lesions (ASCH), low-grade squamous intraepithelial lesions (LSIL), high-grade squamous intraepithelial lesions (HSIL), and squamous cell carcinoma. In Japan, women with high-risk HPV type-positive ASCUS, ASCH, and LSIL or worse undergo colposcopy; histological examination is performed based on the colposcopy findings. Histological diagnosis in this study was based on the World Health Organization classification. Pap test results was evaluated in the present study, since histology data had not been available. Abnormal cervical Pap test results were defined as LSIL or ASCH or worse (LSIL/ASCH+) and HSIL or worse (HSIL+). HPV genotypes were determined using Genosearch-31 (MBL Life Science, Tokyo, Japan), which is a novel genotyping system based on the polymerase chain reaction reverse sequence-specific oligonucleotides Luminex® method (Luminex, Austin, TX, USA) with HPV type-specific primer pairs (21). This system is able to detect 31 HPV genotypes (HPV6, 11, 16, 18, 26, 31, 33, 35, 39, 42, 44, 45, 51, 52, 53, 54, 55, 56, 58, 59, 61, 62, 66, 68, 70, 71, 73, 82, 84, 89, and 90). This test was performed in a commercial laboratory (LSI Medience, Tokyo, Japan).