title: [Sequence polymorphism of human papillomavirus type 16 E7 in cervical cancer].
abstract: OBJECTIVE
  To explore the genetic polymorphism of E7 open-reading frame of human papillomavirus (HPV) type 16 in cervical cancer.
  
  
  METHODS
  The types of HPV was identified by sequence analysis of the PCR product of HPV in cervical cancer tissues. HPV 16 gene fragment in the cervical cancer tissue was amplified by HPV-specific PCR with general consensus primers.
  
  
  RESULTS
  The positivity rate of high-risk HPV types in 50 cases of cervical cancers was 78%. Mixed infection of HPV16 and HPV18 was found in 18 cases, and the infection with HPV16 alone occurred in 15 cases. HPV16 E7 was amplified from 25 out of the 34 cases positive for HPV16. A T-to- C change occurred in the 647th nucleotide in the viral nucleotide sequence, causing conversion of the Asn codon of E7 gene into a Ser codon.
  
  
  CONCLUSIONS
  The most frequently observed substitution in HPV16 E7 open reading frame occurs in the discrete regions of 647-846, and some substitutions result in the same-sense mutation. The hot-spot mutation of HPV16 E7 in cervical cancers in Guangdong Province occurs at the nucleotide 647 and 846 in the DNA sequence.
authors.affiliation: Department of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China. liuxin23@fimmu.com
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.forename: Guo-bing
authors.initials: GB
authors.lastname: Liu
authors.forename: Zhan-jun
authors.initials: ZJ
authors.lastname: Pang
authors.forename: Fu-qi
authors.initials: FQ
authors.lastname: Xing
mesh_terms: D000328:Adult; D001483:Base Sequence; D004279:DNA, Viral / Q000235:genetics*; D005260:Female; D052162:Human papillomavirus 16 / Q000302:isolation & purification*; D006801:Humans; D008969:Molecular Sequence Data; D009856:Oncogene Proteins, Viral / Q000235:genetics*; D050725:Papillomavirus E7 Proteins; D030361:Papillomavirus Infections / Q000821:virology*; D011110:Polymorphism, Genetic; D017422:Sequence Analysis, DNA; D002583:Uterine Cervical Neoplasms / Q000821:virology*
chemical_list: D004279:DNA, Viral; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; C059731:oncogene protein E7, Human papillomavirus type 16