Impact of human papillomavirus types on uterine cervical neoplasia

Human papillomavirus (HPV) is a major cause of cervical cancer. As the natural history of HPV-associated cervical lesions is HPV genotype-dependent, it is important to understand the characteristics of these genotypes and to manage them accordingly. Among high-risk HPVs, HPV16 and 18 are particularly aggressive, together accounting for 70% of HPV genotypes detected in cervical cancer. Other than HPV16 and 18, HPV31, 33, 35, 45, 52, and 58 are also at a high risk of progression to cervical intraepithelial neoplasia (CIN)3 or higher. Recent studies have shown that the natural history of HPV16, 18, 52, and 58, which are frequently detected in Japan, depends on the HPV genotype. For example, HPV16 tends to progress in a stepwise fashion from CIN1 to CIN3, while HPV52 and 58 are more likely to persist in the CIN1 to CIN2 state. Among the high-risk HPVs, HPV18 has some peculiar characteristics different from those of other high-risk HPV types; the detection rate in precancerous lesions is much lower than those of other high-risk HPVs, and it is frequently detected in highly malignant adenocarcinoma and small cell carcinoma. Recent findings demonstrate that HPV18 may be characterized by latent infection and carcinogenesis in stem cell-like cells. In this context, this review outlines the natural history of HPV-infected cervical lesions and the characteristics of each HPV genotype.