Objectives: Transcatheter aortic valve implantation (TAVI) after stentless valve replacement is discussed controversially. Implantation can be challenging due to missing radiopaque marking of the valve plane to fluoroscopically guide implantation depth. Moreover as valve migration was observed early postoperatively, there is concern about sufficient resistance of stentless tissue. We investigated feasibility and success in that scenario.

Objective: Improvements in catheter based valve technologies rise questions regarding patient selection criteria for surgical vs. percutaneous valve replacement. Advanced age and comorbidities (resulting in high logistic EUROscores) have been used as exclusion criteria for conventional valve surgery.

BACKGROUNDFormalin-fixed paraffin-embedded (FFPE) tumor material represents a valuable resource for the analysis of RNA-based biomarkers, both in research laboratories and in routine clinical testing. A robust and automated RNA-extraction method with a high sample throughput is required.METHODSWe evaluated extraction performance for 4 silica-based RNA-extraction protocols: (a) a fully automated, bead-based RNA-isolation procedure; (b) its manual counterpart; (c) a semiautomated bead-based extraction system; and (d) a manual column-based extraction kit. RNA from 360 sections (90 sections per extraction method) of 30 FFPE tumor blocks up to 20 years of age was purified and analyzed by quantitative reverse-transcription PCR for ESR1 (estrogen receptor 1), PGR (progesterone receptor), ERBB2 [v-erb-b2 erythroblastic leukemia viral oncogene homolog 2, neuro/glioblastoma derived oncogene homolog (avian)], and RPL37A (ribosomal protein L37a).RESULTSThe semiautomated protocol gave the best yield. The 3 bead-based methods showed good across-method correlations in both yield and relative mRNA amounts (r = 0.86-0.95 and 0.98, respectively). In contrast, correlations between any of the bead-based methods and the manual column-based method were worse (r = 0.77-0.95 and 0.96, respectively). The fully automated method showed the lowest variation from section to section (root mean square error, 0.32-0.35 Cq, where Cq is the quantification cycle) and required the least hands-on time (1 h).CONCLUSIONSThe fully automated RNA-purification method showed the best reproducibility in gene expression analyses of neighboring sections of tissue blocks between 3 and 20 years of age and required the least overall and hands-on times. This method appears well suited for high-throughput RNA analyses in both routine clinical testing and translational research studies with archived FFPE material.

11032 Background: Personalized cancer therapy depends on the evaluation of tissue-based biomarkers in routine tumor samples. As many new biomarkers are measured on the mRNA level, standardized procedures for mRNA analysis in formalin-fixed, paraffin-embedded (FFPE) tissue are needed. In this study, we present a novel, standardized, and fully automated method for fast isolation of total RNA from FFPE tissue sections. Methods: Tissue samples (n = 501) from 167 breast carcinomas which had been stored between 2 months and 21 years were investigated. Total RNA was extracted from tissue sections using a new method based on silica-coated iron oxide beads in combination with a specific liquid-handling robot. Novel and unique features of the method are an automated extraction-integrated deparaffinization step and a bead-based negative selection step to eliminate any undigested tissue. Yield of RNA was assessed using the Ribogreen assay. mRNA fragment lengths were estimated by reverse transcription PCR (RT-PCR) for G6PDH. Expression of the breast cancer biomarkers ESR1, PGR and HER2 was measured by kinetic RT-PCR (kPCR) and compared with immunohistochemistry (IHC). Results: RNA was successfully isolated from all samples, with a mean yield of 1.4 μg/sample (range: 0.1–7.8 μg) and fragment lengths of at least 150 bp in 99% of samples. PCR analyses could be performed in all samples. Investigating three sections of each tumor, we observed a low section-to-section variability of kPCR results (root of mean squared errors of relative ESR1, PGR or HER2 expression in three sections: 0.2–0.5 Ct values). Comparing kPCR results with IHC, we detected a good concordance between both methods, with agreements of 98.4% (standard error [SE]: 2.7%) for ESR1, 84.4% (SE: 5.3%) for PGR and 89.9% (SE: 8.9%) for HER2. Conclusions: This novel RNA extraction method is a major technical improvement for implementation of reproducible, high-throughput and cost-efficient testing of cancer biomarkers in the clinical routine and in gene-expression research studies using archived FFPE material in molecular labs. [Table: see text]