Supplementary Material for: High Prevalence of Multiple Human Papillomavirus Infection in Japanese Patients with Invasive Uterine Cervical Cancer

<i>Objective:</i> Multiple human papillomavirus (HPV) infection of the uterine cervix has been suggested as a risk factor for persistent HPV infection, resulting in the development of invasive cervical cancer. The aim of this study was to reveal the actual state of multiple HPV infection in Japanese patients with invasive cervical cancer. <i>Methods:</i> Sixty fresh-frozen invasive cervical cancer tissues were examined for genotyping of HPV. The presence of HPV genotypes was determined with an HPV-DNA array, which can discriminate 25 different HPV genotypes with high sensitivity and specificity. <i>Results:</i> Among 60 samples, 59 (96.7%) were positive for HPV. The three common genotypes were HPV-16 (83.3%), HPV-18 (45.0%) and HPV-52 (28.3%). Multiple HPV infection was observed in 47 of 60 samples (78.3%), among which 42 were infected with more than one high-risk genotype (70.0%). Multiple high-risk HPV infection was significantly more prevalent in patients below 40 years old (14/15, 93.3%) than in patients 40 years of age and over (28/45, 62.2%). <i>Conclusion:</i> The HPV-DNA array is the preferred method to detect HPV genotypes. Multiple HPV infection in Japanese patients with invasive cervical cancer seemed to be more frequent than reported in the literature.