Gillard Marc, Tom Westin R, Antic Tatjana, Paner Gladell P, Lingen Mark W, VanderWeele David J
Department of Medicine, University of Chicago Chicago, IL.
Department of Surgery, University of Chicago Chicago, IL.
Am J Transl Res. 2015 Jul 15;7(7):1227-35. eCollection 2015.
Personalization of cancer therapy requires molecular evaluation of tumor tissue. Traditional tissue preservation involves formalin fixation, which degrades the quality of nucleic acids. Strategies to bank frozen prostate tissue can interfere with diagnostic studies. PAXgene is an alternative fixative that preserves protein and nucleic acid quality.
Portions of prostates obtained from autopsy specimens were fixed in either 10% buffered formalin or PAXgene, and processed and embedded in paraffin. Additional sections were immediately embedded in OCT and frozen. DNA and RNA were extracted from the formalin-fixed, PAXgene-fixed, or frozen tissue. Quantitative PCR was used to compare the quality of DNA and RNA obtained from all three tissue types. In addition, 5 μm sections were cut from specimens devoid of cancer and from prostate cancer specimens obtained at prostatectomy and fixed in PAXgene. They were either stained with hematoxylin and eosin or interrogated with antibodies for p63, PSA and p504.
Comparable tissue morphology was observed in both the formalin and PAXgene-fixed specimens. Similarly, immunohistochemical expression of the P63, PSA and P504 proteins was comparable between formalin and PAXgene fixation techniques. DNA from the PAXgene-fixed tissue was of similar quality to that from frozen tissue. RNA was also amplified with up to 8-fold greater efficiency in the PAXgene fixed tissue compared to the formalin-fixed tissue.
Prostate specimens fixed with PAXgene have preserved histologic morphology, stain appropriately, and have preserved quality of nucleic acids. PAXgene fixation facilitates the use of prostatectomy tissue for molecular biology techniques such as next-generation sequencing.
癌症治疗的个性化需要对肿瘤组织进行分子评估。传统的组织保存方法是用福尔马林固定，这会降低核酸质量。储存冷冻前列腺组织的方法可能会干扰诊断研究。PAXgene是一种可保存蛋白质和核酸质量的替代固定剂。
从尸检标本中获取的部分前列腺组织分别用10%缓冲福尔马林或PAXgene固定，处理后包埋于石蜡中。另外的切片立即包埋于OCT中并冷冻。从福尔马林固定、PAXgene固定或冷冻的组织中提取DNA和RNA。采用定量PCR比较从这三种组织类型中获得的DNA和RNA的质量。此外，从无癌标本以及前列腺切除术中获得的前列腺癌标本中切取5μm切片，并用PAXgene固定。切片分别用苏木精和伊红染色，或用p63、PSA和p504抗体进行检测。
在福尔马林固定和PAXgene固定的标本中观察到相似的组织形态。同样，福尔马林固定和PAXgene固定技术之间P63、PSA和P504蛋白的免疫组化表达相当。PAXgene固定组织的DNA质量与冷冻组织的相似。与福尔马林固定组织相比，PAXgene固定组织中的RNA扩增效率也高达8倍。
用PAXgene固定的前列腺标本保留了组织形态，染色适当，并且保留了核酸质量。PAXgene固定便于将前列腺切除组织用于如新一代测序等分子生物学技术。
