scholarly journals Performance of 16S Metagenomic Profiling in Formalin-Fixed Paraffin-Embedded versus Fresh-Frozen Colorectal Cancer Tissues

Cancers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 5421
Author(s):  
Alessandra Borgognone ◽  
Garazi Serna ◽  
Marc Noguera-Julian ◽  
Lidia Alonso ◽  
Mariona Parera ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cancer Genomics ◽  
Internal Quality ◽  
Microbial Composition ◽  
Associated Bacteria ◽  
Formalin Fixed Paraffin ◽  
Formalin Fixed Paraffin Embedded ◽  
Fresh Frozen ◽  
Ffpe Tissues ◽  
Formalin Fixed

Formalin-fixed, paraffin-embedded (FFPE) tissues represent the most widely available clinical material to study colorectal cancer (CRC). However, the accuracy and clinical validity of FFPE microbiome profiling in CRC is uncertain. Here, we compared the microbial composition of 10 paired fresh-frozen (FF) and FFPE CRC tissues using 16S rRNA sequencing and RNA-ISH. Both sample types showed different microbial diversity and composition. FF samples were enriched in archaea and representative CRC-associated bacteria, such as Firmicutes, Bacteroidetes and Fusobacteria. Conversely, FFPE samples were mainly enriched in typical contaminants, such as Sphingomonadales and Rhodobacterales. RNA-ISH in FFPE tissues confirmed the presence of CRC-associated bacteria, such as Fusobacterium and Bacteroides, as well as Propionibacterium allowing discrimination between tumor-associated and contaminant taxa. An internal quality index showed that the degree of similarity within sample pairs inversely correlated with the dominance of contaminant taxa. Given the importance of FFPE specimens for larger studies in human cancer genomics, our findings may provide useful indications on potential confounding factors to consider for accurate and reproducible metagenomics analyses.

scholarly journals Agreement in Breast Cancer Classification between Microarray and Quantitative Reverse Transcription PCR from Fresh-Frozen and Formalin-Fixed, Paraffin-Embedded Tissues

2007 ◽  
Vol 53 (7) ◽  
pp. 1273-1279 ◽  
Author(s):  
Michael Mullins ◽  
Laurent Perreard ◽  
John F Quackenbush ◽  
Nicholas Gauthier ◽  
Steven Bayer ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Training Set ◽  
Pcr Assay ◽  
Gene Set ◽  
Qrt Pcr ◽  
Formalin Fixed Paraffin ◽  
Formalin Fixed Paraffin Embedded ◽  
Fresh Frozen ◽  
Ffpe Tissues ◽  
Formalin Fixed

Abstract Background: Microarray studies have identified different molecular subtypes of breast cancer with prognostic significance. To transition these classifications into the clinical laboratory, we have developed a real-time quantitative reverse transcription (qRT)-PCR assay to diagnose the biological subtypes of breast cancer from fresh-frozen (FF) and formalin-fixed, paraffin-embedded (FFPE) tissues. Methods: We used microarray data from 124 breast samples as a training set for classifying tumors into 4 previously defined molecular subtypes: Luminal, HER2+/ER−, basal-like, and normal-like. We used the training set data in 2 different centroid-based algorithms to predict sample class on 35 breast tumors (test set) procured as FF and FFPE tissues (70 samples). We classified samples on the basis of large and minimized gene sets. We used the minimized gene set in a real-time qRT-PCR assay to predict sample subtype from the FF and FFPE tissues. We evaluated primer set performance between procurement methods by use of several measures of agreement. Results: The centroid-based algorithms were in complete agreement in classification from FFPE tissues by use of qRT-PCR and the minimized “intrinsic” gene set (40 classifiers). There was 94% (33 of 35) concordance between the diagnostic algorithms when comparing subtype classification from FF tissue by use of microarray (large and minimized gene set) and qRT-PCR data. We found that the ratio of the diagonal SD to the dynamic range was the best method for assessing agreement on a gene-by-gene basis. Conclusions: Centroid-based algorithms are robust classifiers for breast cancer subtype assignment across platforms and procurement conditions.

scholarly journals Technical challenges regarding the use of formalin-fixed paraffin embedded (FFPE) tissue specimens for the detection of bacterial alterations in colorectal cancer

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Suk Yee Lam ◽  
Athanasia Ioannou ◽  
Prokopis Konstanti ◽  
Thijmen Visseren ◽  
Michail Doukas ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
16S Rrna ◽  
Nested Pcr ◽  
Amplicon Sequencing ◽  
16S Rrna Amplicon Sequencing ◽  
Bacterial Contaminants ◽  
Formalin Fixed Paraffin ◽  
Formalin Fixed Paraffin Embedded ◽  
Ffpe Tissues ◽  
Formalin Fixed

Abstract Background Formalin-fixed paraffin embedded (FFPE) tissues may provide an exciting resource to study microbial associations in human disease, but the use of these low biomass specimens remains challenging. We aimed to reduce unintentional bacterial interference in molecular analysis of FFPE tissues and investigated the feasibility of conducting quantitative polymerase chain reaction (qPCR) and 16S rRNA amplicon sequencing using 14 colorectal cancer, 14 normal adjacent and 13 healthy control tissues. Results Bacterial contaminants from the laboratory environment and the co-extraction of human DNA can affect bacterial analysis. The application of undiluted template improves bacterial DNA amplification, allowing the detection of specific bacterial markers (Escherichia coli and Faecalibacterium prausnitzii) by qPCR. Nested and non-nested PCR-based 16S rRNA amplicon sequencing approaches were employed, showing that bacterial communities of tissues and paired paraffin controls cluster separately at genus level on weighted Unifrac in both non-nested (R2 = 0.045; Pr(> F) = 0.053) and nested (R2 = 0.299; Pr(> F) = 0.001) PCR datasets. Nevertheless, considerable overlap of bacterial genera within tissues was seen with paraffin, DNA extraction negatives (non-nested PCR) or PCR negatives (nested PCR). Following mathematical decontamination, no differences in α- and β diversity were found between tumor, normal adjacent and control tissues. Conclusions Bacterial marker analysis by qPCR seems feasible using non-normalized template, but 16S rRNA amplicon sequencing remains challenging. Critical evaluation of laboratory procedures and incorporation of positive and negative controls for bacterial analysis of FFPE tissues are essential for quality control and to account for bacterial contaminants.

scholarly journals Characterization of epididymal and testicular histologic lesions and use of immunohistochemistry and PCR on formalin-fixed tissues to detect Brucella canis in male dogs

2021 ◽  
pp. 104063872098688
Author(s):  
Andrea M. Camargo-Castañeda ◽  
Lauren W. Stranahan ◽  
John F. Edwards ◽  
Daniel G. Garcia-Gonzalez ◽  
Leonardo Roa ◽  
...  
Keyword(s):  
Accurate Diagnosis ◽  
Testicular Atrophy ◽  
Detection Techniques ◽  
Formalin Fixed Paraffin ◽  
Brucella Canis ◽  
Formalin Fixed Paraffin Embedded ◽  
Variable Sensitivity ◽  
Ffpe Tissues ◽  
Formalin Fixed

In male dogs, Brucella canis frequently causes epididymitis, ultimately resulting in testicular atrophy and infertility. Although B. canis predominantly affects the epididymis, the misleading term “orchitis” is still commonly used by clinicians. Of additional concern, diagnosis in dogs remains challenging because of variable sensitivity and specificity of serologic assays and fluctuations in bacteremia levels in infected dogs, reducing the sensitivity of blood culture. We describe here the histologic lesions in the scrotal contents of 8 dogs suspected of being infected with B. canis and clinically diagnosed with orchitis. We explored the possibility of using immunohistochemistry (IHC) and real-time PCR (rtPCR) in formalin-fixed, paraffin-embedded (FFPE) tissues to detect the presence of B. canis. Epididymitis of variable chronicity was identified in all 8 dogs, with only 3 also exhibiting orchitis. Using rtPCR, the presence of B. canis was identified in 4 of 8 dogs, with 3 of these 4 dogs also positive by IHC. These results suggest that rtPCR and IHC are promising techniques that can be used in FFPE tissues to detect B. canis when other detection techniques are unavailable. Additionally, accurate recognition of epididymitis rather than orchitis in suspect cases could aid in accurate diagnosis.

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