Template direct dye-terminator incorporation with fluorescence-polarization (TDI-FP assay) is a technology for genotyping single nucleotide polymorphisms (SNPs). To apply this method in analyses of A647G variation in human papillomavirus (HPV) 16 E7 gene from HPV 16-positive cervical tissues, a total of 91 and 49 HPV 16-positive DNA samples obtained from women with cervical cancer and normal/inflamed cervices living in Shaanxi in northwest China were subjected to the partial E7 gene PCR with nucleotide (nt) 647 in the products. Then, the oligonucleotide probe designed to anneal immediately to nt 647 was hybridized to the template within the PCR amplicons, and extended specifically by TAMRA-ddTTP or R110-ddCTP directed by the base at nt 647. The increasing FP values were read and the base at nt 647 was identified. The prevalence of nt 647 A→G was 35.71% (50/140). The variation 647G detected in 42.86% (39/91) of women with cervical cancer was significantly higher than 22.45% (11/49) detected in those with normal/inflamed cervices (x2 = 5.778, P = 0.016). The odds ratio (OR) between these two groups was 2.59 (95% confidence interval=l.17～5.71). The results demonstrate that TDI-FP method can be potentially applied in analysis of interest point mutations in HPVs. The incidence and risk implication of HPV 16 A647G variant infection in Shaanxi, China, displays significant geographic difference from other areas. The HPV 16 with E7 gene A647G point mutation appears to have a higher risk for invasive cervical cancer in women living in Shaanxi.

OBJECTIVETo develop a simple, cheap, quick, accurate and practical method for a high throughout genotypes assay of human papillomavirus (HPV) DNA.

METHODSCrude DNA was extracted by a simplified proteinase K digesting method. HPV common conservative primers: GP5+/6+ system was used to amplify HPV DNA in 127 samples of condylomata acuminatum (CA) and cervical scrapes by PCR, then the PCR product was assayed using a template directing terminator incorporation (TDI) and genotypes were detected with fluorescence polarization (FP). Major HPVs type-specific probes (HPV6, 11, 16, 18, 31, 33, 35 and 58) designed by us were hybridized with the specific PCR products and a special fluorescent ddNTP terminator was directly added to the end of the probe under direction of specific PCR products. The results were measured with FP and compared with the results of the DNA sequence.

RESULTSCompared with the results of DNA sequencing, the results detected with fluorescence polarization were all correct. The proposed method could detect more than one type of HPV infection, but DNA sequencing method could not. The positive rate of HPV was 100% in 78 CA biopsies. Among them, there were 14 HPV double infections [HPV6B and 11 (9 cases), HPV11 and 16 (4), HPV11 and 18 (1)], 5 HPV triple infections [HPV6B, 11 and 16 (4), HPV11, 16 and 18 (1)], and one HPV quadruple infection (HPV6B, 11, 16 and 18). The positive rate of HPV was 77% in the 49 cervical scrapes. Six HPV double infections [HPV6B and 11 (2), HPV11 and 16 (1), HPV6B and 16 (1), HPV16 and 18 (1), HPV18 and 58 (1)], 3 HPV triple infections [HPV6B, 11 and 16 (2), HPV11, 16 and 18 (1)] and one HPV quadruple infection (HPV6B, 11, 16 and 18) were detected in cervical cancer scrapes.

CONCLUSIONSThe proposed method allowed a high throughout, special, simple, rapid, automatic and economical detection of HPV-DNA genotyping without a use of labeling probes. It can detect multiple HPV genotype infection and will be and useful tool in HPV genotype screening.

Base Sequence ; DNA, Viral ; analysis ; Fluorescence Polarization ; methods ; Genotype ; Humans ; Papillomaviridae ; genetics ; Papillomavirus Infections ; diagnosis ; Polymerase Chain Reaction ; Tumor Virus Infections ; diagnosis