HPV prevalence, E6 sequence variation and physical state of HPV16 isolates from patients with cervical cancer in Sichuan, China.
OBJECTIVE
Infection with high-risk human papillomavirus (hr-HPV) is an important factor associated with cervical cancer. The genetic mutation of HPV16 E6 and integration of HPV16 DNA in the cervical carcinoma tissues are considered important genetic changes in cervical lesion progression. But the studies of hr-HPV epidemiology are relatively less in the area of Sichuan, China. Therefore, we investigated the prevalence of 9 high-risk subtypes and analyzed the genetic mutation characteristic of HPV16 E6 and physical state of HPV16 DNA.


METHODS
The fragments of L1 and E6 genes were amplified by PCR or nested PCR and then directly sequenced. Further, the multiplex PCR for HPV16 E2 and E6 genes was performed for detection of integration.


RESULTS
HPV16, 58 and 18 were prominent, accounting for 78.6%, 20.0% and 9.7%, respectively in 145 isolates. E6 variants revealed that the European (EP) prototype and East Asia (EA) strain were 26 (23.0%) and 34 (30.1%), respectively. Furthermore, there were 14 base substitutions in E6 regions of the study group, of which 12 resulted in amino acid changes and the rest was silent mutation. Significantly, the 240G substitution exactly located the P53 degradation site. Overall, 8 of 114 (7.0%) isolates only contained integrated HPV16 DNA, 43 (37.7%) only contained episomal DNA and 63 (55.3%) contained both integrated and episomal DNA. The proportion of disruption of an intact E2 gene in the patients with cervical cancer is much lower than that in the previous studies.


CONCLUSIONS
HPV16, 58 and 18 were mainly prevailing subtypes in patients with cervical cancer from Sichuan areas, China and EP/EA strains were predominant in these areas. Some mutations of E6 gene, which lead to the amino acid changes, may be more potentially carcinogenic and the proportion of disruption of an intact E2 gene is much lower.
Qiu
Ai-Dong
AD
College of Life Science, Vaccines Research Center, Jilin University, Changchun 130012, China.
Wu
En-Qi
EQ
Yu
Xiang-Hui
XH
Jiang
Chun-Lai
CL
Jin
Ying-Hua
YH
Wu
Yong-Ge
YG
Chen
Yue
Y
Chen
Yan
Y
Shan
Ya-Ming
YM
Zhang
Guo-Nan
GN
Fan
Ying
Y
Zha
Xiao
X
Kong
Wei
W
D000230:Adenocarcinoma / Q000453:epidemiology / Q000821:virology; D000293:Adolescent; D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000453:epidemiology / Q000821:virology; D002681:China / Q000453:epidemiology; D004279:DNA, Viral / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D005260:Female; D052162:Human papillomavirus 16 / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D008875:Middle Aged; D009154:Mutation; D009856:Oncogene Proteins, Viral / Q000235:genetics*; D030361:Papillomavirus Infections / Q000453:epidemiology* / Q000821:virology*; D016133:Polymerase Chain Reaction; D015995:Prevalence; D012097:Repressor Proteins / Q000235:genetics*; D002583:Uterine Cervical Neoplasms / Q000453:epidemiology* / Q000821:virology*; D016662:Virus Integration
D004279:DNA, Viral; D004268:DNA-Binding Proteins; C054855:E2 protein, Human papillomavirus type 16; C068651:E6 protein, Human papillomavirus type 16; D009856:Oncogene Proteins, Viral; D012097:Repressor Proteins