Castle Philip E, Solomon Diane, Hildesheim Allan, Herrero Rolando, Concepcion Bratti M, Sherman Mark E, Cecilia Rodriguez Ana, Alfaro Mario, Hutchinson Martha L, Terence Dunn S, Kuypers Jane, Schiffman Mark
The National Cancer Institute, Division of Cancer Epidemiology and Genetics, Rockville, Maryland 20892-7234, USA.
Cancer. 2003 Apr 25;99(2):89-96. doi: 10.1002/cncr.11058.
Exfoliated cervical cell specimens collected in PreservCyt, a methanol-based medium used in ThinPrep liquid-based cytology, have been archived in epidemiologic studies. However, long-term DNA stability and cytologic stability of these biospecimens have not been evaluated.
Cervical specimens were collected into PreservCyt from participants in a natural history study of human papillomavirus (HPV) infection and cervical carcinoma in Guanacaste, Costa Rica (1993-2000), and stored at ambient temperatures. Thirty specimens classified as low-grade squamous intraepithelial lesions by liquid-based cytology were randomly chosen from each collection year (except for 1994) and selectively assessed for molecular and cytologic stability. Specimens were tested in 2001 for 1) HPV DNA by the Hybrid Capture 2 test, 2) beta-globin DNA by polymerase chain reaction amplification of multiple length fragments (268, 610, and 1327 bp), and 3) nuclear preservation by visual inspection of newly made liquid-based cytology slides. All testing was done masked to year of collection. Associations of stability and storage time were evaluated using standard contingency tables and chi-square tests for trend.
Human papillomavirus DNA, as detected by the Hybrid Capture 2 test, was unaffected by storage time. Stability of beta-globin DNA (P(Trend) < 0.0001) and nuclear preservation (P(Trend) < 0.0001) declined with increasing storage time. Approximately 15% of specimens could not be amplified for any beta-globin DNA fragment after 5 years of storage (collected in 1996). In addition, cytology slides made from 41% specimens were rated as marginal (32%) or unsatisfactory (9%) after 8 years of storage (collected in 1993).
Cervical specimens archived in PreservCyt underwent partial DNA and cytologic degradation after several years of storage. Methodologic studies to optimize long-term storage of cervical cells for epidemiologic studies of cervical carcinoma are needed.
在液基细胞学中用于ThinPrep的基于甲醇的培养基PreservCyt中收集的脱落宫颈细胞标本已存档于流行病学研究中。然而，这些生物标本的长期DNA稳定性和细胞学稳定性尚未得到评估。
从哥斯达黎加瓜纳卡斯特的人乳头瘤病毒（HPV）感染和宫颈癌自然史研究的参与者中收集宫颈标本并置于PreservCyt中，于室温下保存。从每个收集年份（1994年除外）中随机选择30个经液基细胞学分类为低度鳞状上皮内病变的标本，并对其分子和细胞学稳定性进行选择性评估。2001年对标本进行检测，包括：1）通过杂交捕获2试验检测HPV DNA；2）通过聚合酶链反应扩增多个长度片段（268、610和1327 bp）检测β-珠蛋白DNA；3）通过目视检查新制备的液基细胞学载玻片评估细胞核保存情况。所有检测均在不知道收集年份的情况下进行。使用标准列联表和趋势卡方检验评估稳定性与储存时间的关联。
通过杂交捕获2试验检测到的人乳头瘤病毒DNA不受储存时间影响。β-珠蛋白DNA的稳定性（P趋势<0.0001）和细胞核保存情况（P趋势<0.0001）随储存时间延长而下降。储存5年后（1996年收集），约15%的标本无法扩增出任何β-珠蛋白DNA片段。此外，储存8年后（1993年收集），41%标本制成的细胞学载玻片被评为边缘（32%）或不满意（9%）。
保存在PreservCyt中的宫颈标本在储存数年之后发生了部分DNA和细胞学降解。需要开展方法学研究以优化用于宫颈癌流行病学研究的宫颈细胞长期储存。
