title: Association of human papillomavirus 16 E6 variants with cervical carcinoma and precursor lesions in women from Southern Mexico.
abstract: BACKGROUND
  HPV 16 is the cause of cervical carcinoma, but only a small fraction of women with HPV infection progress to this pathology. Besides persistent infection and HPV integration, several studies have suggested that HPV intratype variants may contribute to the development of cancer. The purpose of this study was to investigate the nucleotide variability and phylogenetically classify HPV 16 E6 variants circulating over a period of 16 years in women from Southern Mexico, and to analyze its association with precursor lesions and cervical carcinoma.
  
  
  METHODS
  This study was conducted in 330 cervical DNA samples with HPV 16 from women who were residents of the State of Guerrero, located in Southern Mexico. According of cytological and/or histological diagnosis, samples were divided into the following four groups: no intraepithelial lesion (n = 97), low-grade squamous intraepithelial lesion (n = 123), high-grade squamous intraepithelial lesion (n = 19) and cervical carcinoma (n = 91). HPV 16 E6 gene was amplified, sequenced and aligned with reference sequence (HPV 16R) and a phylogenetic tree was constructed to identify and classify HPV 16 variants. Chi squared was used and data analysis and statistics were done with SPSS Statistics and STATA softwares.
  
  
  RESULTS
  Twenty seven HPV 16 E6 variants were detected in women from Southern Mexico, 82.12% belonged to the EUR, 17.58% to AA1 and 0.3% to Afr2a sublineages. The most common was E-G350 (40%), followed by E-prototype (13.03%), E-C188/G350 (11.82%), AA-a (10.61%), AA-c (6.07%) and E-A176/G350 (5.15%). Eight new E6 variants were found and 2 of them lead to amino acid change: E-C183/G350 (I27T) and E-C306/G350 (K68T). The HPV 16 variant that showed the greatest risk of leading to the development of CC was AA-a (OR = 69.01, CI = 7.57-628.96), followed by E-A176/G350 (OR = 39.82, CI = 4.11-386.04), AA-c (OR = 21.16, CI 2.59-172.56), E-G350 (OR = 13.25, CI = 2.02-87.12) and E-C188/G350 (OR = 10.48, CI = 1.39-78.92).
  
  
  CONCLUSIONS
  The variants more frequently found in women with cervical carcinoma are E-G350, AA-a, AA-c, E-C188/G350 and E-A176/G350. All of them are associated with the development of cervical carcinoma, however, AA-a showed the highest association. This study reinforces the proposal that HPV 16 AA-a is an oncogenic risk for cervical carcinoma progression in Mexico.
authors.affiliation: Laboratorio de Biomedicina Molecular, Unidad Académica de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Chilpancingo, Guerrero, México. julioortiz771210@gmail.com.
authors.forename: Julio
authors.initials: J
authors.lastname: Ortiz-Ortiz
authors.affiliation: Laboratorio de Citopatología, Unidad Académica de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Chilpancingo, Guerrero, México. luzdelcarmen14@gmail.com.
authors.forename: Luz del Carmen
authors.initials: Ldel C
authors.lastname: Alarcón-Romero
authors.affiliation: Instituto Estatal de Cancerología "Dr. Arturo Beltrán Ortega", Acapulco, Guerrero, México. marcoajl16@gmail.com.
authors.forename: Marco Antonio
authors.initials: MA
authors.lastname: Jiménez-López
authors.affiliation: Instituto Estatal de Cancerología "Dr. Arturo Beltrán Ortega", Acapulco, Guerrero, México. victhorgarzon@hotmail.com.
authors.forename: Víctor Hugo
authors.initials: VH
authors.lastname: Garzón-Barrientos
authors.affiliation: Molecular Biology and Biochemistry, School of Biological Sciences, University of California Irvine, Irvine, CA, USA. itzel14@yahoo.com.
authors.forename: Itzel
authors.initials: I
authors.lastname: Calleja-Macías
authors.affiliation: Departamento de Bioquímica y Medicina Molecular, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, México. habarrera@gmail.com.
authors.forename: Hugo Alberto
authors.initials: HA
authors.lastname: Barrera-Saldaña
authors.affiliation: Laboratorio de Biomedicina Molecular, Unidad Académica de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Chilpancingo, Guerrero, México. leyvamarco13@gmail.com.
authors.forename: Marco Antonio
authors.initials: MA
authors.lastname: Leyva-Vázquez
authors.affiliation: Laboratorio de Biomedicina Molecular, Unidad Académica de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Chilpancingo, Guerrero, México. b.illadesaguiar@gmail.com.
authors.forename: Berenice
authors.initials: B
authors.lastname: Illades-Aguiar
mesh_terms: D000328:Adult; D002277:Carcinoma / Q000473:pathology / Q000821:virology*; D005260:Female; D052162:Human papillomavirus 16 / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D006801:Humans; D008800:Mexico; D008969:Molecular Sequence Data; D030361:Papillomavirus Infections / Q000473:pathology / Q000821:virology*; D010802:Phylogeny; D002583:Uterine Cervical Neoplasms / Q000473:pathology / Q000821:virology*; D055815:Young Adult