| Cervical cancer is one of the most common cancer in women worldwide.The persistent infection of human papillomavirus(HPV)is considered to be the most important cause.HPV DNA is found in the cervical carcinoma tissues of more than 80%,some areas even close to 100%.Depending on the carcinogenic potential,HPV is divided into high-risk(HR),probably high-risk and low-risk types.The types that are associated with cervical cancer often designated as high-risk types.There are 15 high-risk HPV types,including HPV39.It has been reported that the positive rate of HPV39 in cervical cancer is about 1.3%and even up to 5.8%in some areas.HPV39 is a member of the papillomaviridae-alpha papillomavirus-species 7 with a double stranded circular DNA genome about 7833 base pairs in size.It has six open reading frames which are E6,E7,El,E2,E4,E5,L1 and L2 respectively.We searched HPV39 DNA sequences in GenBank database.Until January 14,2016,there are 121 sequences totally.And among them,twenty complete genome sequences from different countries and regions were clustered into two lineages designated A and B.Lineage A was further divided into sublineage A1 and A2.But the complete sequence has not been reported in China mainland.Different HPV types have different pathogenicity to cervical epithelium.The epidemiological characteristics of HPV may vary from area to area.Therefore,it is necessary to explore the characteristics of the population distribution of HPVs,analysis the isolates and establish a standard.They will help to control the HPV infection,study the pathogenic mechanism of cervical cancer and even prevent cervical cancer.To investigate the infection rate of human papillomavirus type 39 and its distribution in Beijing,a retrospective analysis of 19018 women who had HPV genotyping and thinprep cytology test within 30 days between January 2013 and July 2014 from the People's Liberation Army General Hospital was carried out.In 19018 samples,3623 cases were HR-HPV positive and 518 cases were HPV39 positive.The positive rate of HPV39 was 2.72%in total population and 14.30%in HR-HPV positive people.The age-specific prevalence of HPV39 were as follows:21-25 years old(2.98%),26-30 years old(2.53%),31-35 years old(2.37%),36-40 years old(1.48%),41-45 years old(2.08%),46-50 years old(2.44%),51-55 years old(2.23%),56-60 years old(1.92%)and over 61 years(1.13%).The positive rate of HPV39 in NILM,ASC-US,LSIL and HSIL were 15.08%,14.29%,18.52%and 5.71%.Fifteen positive samples of HPV39 were amplified by polymerase chain reaction(PCR)and then sequenced.Compared to European prototype(assession number:M62849),there were 121 mutation sites with the mutation rate of 1.54%.The phylogenetic tree according to complete nucleotide sequences showed that fifteen isolates of this research were belong to lineage A,including twelve isolates belong to sublineage Al.The twelve isolates mainly concentrated in two branches.The first branch included six isolates(samples J32-42,J05-75,J04-23,J31-13,J05-20 and J39-50)with six continuous mutation sites in 792,937,3316,3500,3599 and 5383.The second branch had three isolates with four continuous mutation sites in 87,3922,6428 and 7214.And the other three isolates belong to sublineage A2 with seven continuous mutation sites in 558,853,1731,2857,3497,4354 and 6569.Fourthermore,based on the domestic HPV39 isolate,HPV39 PCR fragments were ligated into pMD18-T vector by TA cloning.Through this method,we established HPV39 standard samples.The conclusions were as follows:(1)Age subgroup analysis showed two peaks in the age groups 21-25 and 46-50.The distribution of HPV39 in cervical lesions rose first and then declined,with the highest positive rate in LSIL of 18.52%.(2)Three HPV39 isolates were confirmed in this research.(3)We established HPV39 standard samples which cover its full genome. |
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