The feasibility of gene expression profiling generated in fine-needle aspiration specimens from patients with follicular lymphoma and diffuse large B-cell lymphoma
✍ Scribed by Stelow, Edward B. ;Hong, Sueng-Mo ;Covell, Jamie L. ;Moskaluk, Christopher A.
- Publisher
- John Wiley and Sons
- Year
- 2007
- Tongue
- English
- Weight
- 45 KB
- Volume
- 111
- Category
- Article
- ISSN
- 0008-543X
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✦ Synopsis
W e have read with interest the articles published in Cancer Cyto- pathology regarding the use of find-needle aspiration (FNA) specimens for gene expression profiling. [1][2][3] We agree that FNA may allow for the procurement of ample tissue for subsequent gene expression analysis and are optimistic for such use in patient care and the real-time assessment of in vivo tumors.
We would like to express our concern over a couple of difficulties that may come to be issues. It is unclear whether the sampling of bench tissues will predict the sampling of in vivo tumors and whether the quantities of tumor gathered from site to site will have a sufficient amount of RNA for testing. Also, individual samples from a single tumor can vary significantly from pass to pass; thus, it is difficult to predict the cellularity and quality of a sample without assessing it cytologically. We are not sure, then, whether material should be collected directly into RNA-preserving or extracting solutions. When true patient care and costs become issues, it probably will be necessary to know that ample neoplastic tissue is being submitted for analysis.
We imagine that samples will need to be split. Ideally, the tissue could be collected in a solution that preserves both cytology and RNA. Recently, we tested the function of Preservcyt in just such a manner. Fourteen aspirates were performed on 7 tumors from various sites using 23-and 25-gauge needles with 20 revolutions and a single pass. Material was sprayed immediately into Preservcyt fluid, and the needles were rinsed. Fifteen milliliters of fluid were spun down, decanted, and frozen at À808C, and the remaining sample was submitted for Thin Prep preparation. RNA was extracted using RNeasy minispin columns (Qiagen). RNA quantity was determined by A260 spectroscopy, and RNA quality was assessed using microcapillary electrophoresis (RNA Nano LabChip run on a 2100 Bioanalyzer; Agilent Technologies).
Cytologic preparations were diagnostic. RNA quantity varied and was maximized by using a 23-gauge needle (1.37 mg per pass). RNA quality also varied but appeared to be degraded most with samples that remained in Preservcyt for an extended time before freezing. Three of the 5 samples that were frozen the same day as the aspirations showed RNA of good quality (28S/18S>1).
We imagine that other solutions may be developed that allow for sufficient preservation of cytology and RNA. We believe that, prior to microarray analysis, FNA samples will have to be assessed morphologically.