title: Polymerase chain reaction and deoxyribonucleic acid-sequencing based study on distribution of human papillomavirus 16/18 among histopathological types of cervical intra-epithelial neoplasia and primary invasive cervical carcinoma: A scenario in North Bengal, India.
abstract: BACKGROUND
  Human papillomavirus (HPV) types 16/18 are reportedly most common in cervical cancer (CaCx) with geographical variation of genotypes. HPV16 predominates both in squamous cell carcinoma (SCC) and adenocarcinoma in India, contrary to reported global predominance of HPV18 in the latter. Our study was aimed to determine the occurrence of HPV16/18 among histopathological types of cervical intra-epithelial neoplasia (CIN) and invasive CaCx from North Bengal, India and to identify any major deviation from the known Indian scenario of distribution of HPV16/18 genotypes in cases of SCC and adenocarcinoma.
  
  
  METHODS
  This was a retrospective, cross-sectional, case-only type of study, in which 40 cases were histopathologically diagnosed as CIN/CaCx, on which polymerase chain reaction (PCR), deoxyribonucleic acid (DNA)-sequencing and bioinformatics by basic search local alignment tool were performed for HPV-genotyping.
  
  
  METHODS
  The distribution of HPV genotypes among cases of SCC and adenocarcinoma was compared by Fisher's exact-test.
  
  
  RESULTS
  HPV was detected in 97.5% (39/40) cases. HPV16-infected cases (32/39; 82.05%) predominated over HPV18-infected ones (7/39; 17.95%). However, HPV18-only infection was significantly (P = 0.0045, one-sided Fisher's exact test) more among adenocarcinoma (3/4; 75%) than SCC (2/26; 7.69%) contrary to HPV16-only infection (SCC = 24/26, 92.31%; adenocarcinoma = 1/4; 25%) whereas both CIN3 cases were HPV16-positive.
  
  
  CONCLUSIONS
  Predominance of HPV18 over HPV16 in cases of adenocarcinoma in this region was contrasting to that of earlier Indian studies suggesting research on HPV18 related cervical carcinogenesis. PCR and DNA-sequencing could prove to be highly effective tools in HPV detection and genotyping. The study reported HPV16/18 infection in almost 98% of the cases, the knowledge about which might prove useful in future population based studies on HPV genotyping and designing of appropriate HPV-vaccines for this region.
authors.affiliation: Department of Pathology, North Bengal Medical College and Hospital, Siliguri, India ; Department of Pathology, DESUN (NEON) Lab, Kolkata, West Bengal, India.
authors.forename: Prithwijit
authors.initials: P
authors.lastname: Ghosh
authors.affiliation: Human Genetics Unit, Biological Sciences Division, Indian Statistical Institute, Kolkata, West Bengal, India ; Cancer Biology and Inflammatory Disorder Division, Indian Institute of Chemical Biology, Kolkata, West Bengal, India.
authors.forename: Damayanti Das
authors.initials: DD
authors.lastname: Ghosh
authors.affiliation: Department of Pathology, North Bengal Medical College and Hospital, Siliguri, India.
authors.forename: Amita
authors.initials: A
authors.lastname: Majumdar Giri
authors.affiliation: Human Genetics Unit, Biological Sciences Division, Indian Statistical Institute, Kolkata, West Bengal, India ; Department of Gynecology and Obstetrics, National Institute of Biomedical Genomics, Kalyani, West Bengal, India.
authors.forename: Sharmila
authors.initials: S
authors.lastname: Sengupta
authors.affiliation: Department of Gynecology and Obstetrics, North Bengal Medical College and Hospital, Siliguri, Kolkata, West Bengal, India ; Department of Gynecology and Obstetrics, Nil Ratan Sircar Medical College, Kolkata, West Bengal, India.
authors.forename: Chandana
authors.initials: C
authors.lastname: Das
authors.affiliation: Human Genetics Unit, Biological Sciences Division, Indian Statistical Institute, Kolkata, West Bengal, India.
authors.forename: Indranil
authors.initials: I
authors.lastname: Mukhopadhyay
keywords: Cervical cancer; North Bengal; histopathology; human papillomavirus 16/18; polymerase chain reaction