Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland, USA.
J Clin Microbiol. 2012 May;50(5):1564-70. doi: 10.1128/JCM.06240-11. Epub 2012 Feb 15.
Carcinogenic human papillomavirus (HPV) infections are necessary causes of most anogenital cancers. Viral load has been proposed as a marker for progression to cancer precursors but has been confirmed only for HPV16. Challenges in studying viral load are related to the lack of validated assays for a large number of genotypes. We compared viral load measured by Linear Array (LA) HPV genotyping with the gold standard, quantitative PCR (Q-PCR). LA genotyping and Q-PCR were performed in 143 cytology specimens from women referred to colposcopy. LA signal strength was measured by densitometry. Correlation coefficients and receiver operating characteristic (ROC) analyses were used to evaluate analytical and clinical performance. We observed a moderate to strong correlation between the two quantitative viral load measurements, ranging from an R value of 0.61 for HPV31 to an R value of 0.86 for HPV52. We also observed agreement between visual LA signal strength evaluation and Q-PCR. Both quantifications agreed on the disease stages with highest viral load, which varied by type (cervical intraepithelial neoplasia grade 2 [CIN2] for HPV52, CIN3 for HPV16 and HPV33, and cancer for HPV18 and HPV31). The area under the curve (AUC) for HPV16 Q-PCR at the CIN3 cutoff was 0.72 (P = 0.004), and the AUC for HPV18 LA at the CIN2 cutoff was 0.78 (P = 0.04). Quantification of LA signals correlates with the current gold standard for viral load, Q-PCR. Analyses of viral load need to address multiple infections and type attribution to evaluate whether viral load has clinical value beyond the established HPV16 finding. Our findings support conducting comprehensive studies of viral load and cervical cancer precursors using quantitative LA genotyping data.
致癌型人乳头瘤病毒（HPV）感染是大多数肛门生殖器癌症的必要病因。病毒载量曾被提议作为癌症前体进展的标志物，但仅在 HPV16 中得到证实。研究病毒载量的挑战与缺乏大量基因型的验证检测有关。我们比较了线性阵列（LA）HPV 基因分型测定的病毒载量与金标准定量聚合酶链反应（Q-PCR）。对 143 例细胞学标本进行了 LA 基因分型和 Q-PCR 检测，这些标本来自转诊行阴道镜检查的女性。通过密度计测量 LA 信号强度。相关系数和受试者工作特征（ROC）分析用于评估分析和临床性能。我们观察到两种定量病毒载量测量之间存在中度至强相关性，范围从 HPV31 的 R 值为 0.61 到 HPV52 的 R 值为 0.86。我们还观察到 LA 信号强度的视觉评估与 Q-PCR 之间存在一致性。两种定量方法都同意病毒载量最高的疾病阶段，这因类型而异（HPV52 为宫颈上皮内瘤变 2 级[CIN2]，HPV16 和 HPV33 为 CIN3，HPV18 和 HPV31 为癌症）。CIN3 截止值时 HPV16 Q-PCR 的曲线下面积（AUC）为 0.72（P=0.004），CIN2 截止值时 HPV18 LA 的 AUC 为 0.78（P=0.04）。LA 信号的定量与当前病毒载量的金标准 Q-PCR 相关。病毒载量的分析需要解决多重感染和类型归因问题，以评估病毒载量除了已确立的 HPV16 发现之外是否具有临床价值。我们的研究结果支持使用定量 LA 基因分型数据对病毒载量和宫颈癌前体进行综合研究。
