title: HPV infection, anal intra-epithelial neoplasia (AIN) and anal cancer: current issues.
abstract: BACKGROUND
  Human papillomavirus (HPV) is well known as the major etiological agent for ano-genital cancer. In contrast to cervical cancer, anal cancer is uncommon, but is increasing steadily in the community over the last few decades. However, it has undergone an exponential rise in the men who have sex with men (MSM) and HIV + groups. HIV + MSM in particular, have anal cancer incidences about three times that of the highest worldwide reported cervical cancer incidences.
  
  
  CONCLUSIONS
  There has therefore traditionally been a lack of data from studies focused on heterosexual men and non-HIV + women. There is also less evidence reporting on the putative precursor lesion to anal cancer (AIN - anal intraepithelial neoplasia), when compared to cervical cancer and CIN (cervical intraepithelial neoplasia). This review summarises the available biological and epidemiological evidence for HPV in the anal site and the pathogenesis of AIN and anal cancer amongst traditionally non-high risk groups.
  
  
  CONCLUSIONS
  There is strong evidence to conclude that high-grade AIN is a precursor to anal cancer, and some data on the progression of AIN to invasive cancer.
authors.affiliation: Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK.
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Stanley
authors.forename: David M
authors.initials: DM
authors.lastname: Winder
authors.forename: Jane C
authors.initials: JC
authors.lastname: Sterling
authors.forename: Peter K C
authors.initials: PK
authors.lastname: Goon
mesh_terms: D001005:Anus Neoplasms / Q000453:epidemiology / Q000473:pathology* / Q000821:virology*; D002278:Carcinoma in Situ / Q000453:epidemiology / Q000473:pathology / Q000821:virology*; D018450:Disease Progression; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D030361:Papillomavirus Infections / Q000453:epidemiology / Q000473:pathology*