Human papillomavirus 51 (HPV51) is a high-risk member of the Alphapapillomavirus genus with a circular double-stranded DNA genome. Like other human papillomaviruses it infects squamous epithelium through microabrasions and establishes its genome as an episome in basal keratinocytes. Persistent infection with HPV51 has been associated with carcinogenesis.
Virology & Oncogenic Mechanisms
HPV51 is one of the high risk types recognized by cancer agencies. Its approximately 8 kb genome encodes early proteins E1–E7 involved in replication and modulation of host cell cycle and late structural proteins L1 and L2. The E6 and E7 oncoproteins bind and degrade tumour suppressors p53 and retinoblastoma proteins, leading to dysregulated cell proliferation. The virus replicates in stratified epithelium: after entry via heparan sulfate binding, the genome is maintained as a low‑copy episome in the basal layer and amplifies as cells differentiate. Integration of viral DNA into the host genome with constitutive E6/E7 expression is a critical step in malignant progression. While HPV16 and HPV18 cause most HPV related cancers, high‑risk types including 31, 33, 35, 39, 45, 51, 52, 56, 58 and 59 can also contribute to cervical carcinoma.
Clinical Impact and Prevention
Persistent infection with HPV51 has been detected in high‑grade squamous intraepithelial lesions and invasive cervical cancers, though it is less prevalent than HPV16 or HPV18. It can also be present in cancers of the vagina, vulva, penis and anus. The majority of HPV51 infections are transient and are cleared by the immune system within one to two years. Current prophylactic vaccines (bivalent, quadrivalent and nonavalent) do not include HPV51, so prevention relies on limiting transmission and early detection. Regular cervical screening with Pap tests and high‑risk HPV DNA testing allows identification of women infected with HPV51 and appropriate follow‑up. Safe sexual practices and smoking cessation reduce the risk of persistent infection. Research into broader vaccines and understanding of HPV51’s epidemiology continues. HPV51 is a high‑risk papillomavirus that can contribute to cervical and other anogenital cancers when infection persists. Vigilant screening and risk-reducing behaviours are important because current vaccines do not target this type. Related Terms: HPV16, HPV18, HPV45, High‑risk HPV, Cervical screening