English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Background: Reverse phase protein array (RPPA) allows precise protein quantification. Use of homogenised samples confounds interpretation due to uncertainty of cellular content. We hypothesised that antibodies AE1/3 (Type I/II keratins) and BerEP4 (EpCAM) could help to quantify epithelium in tissue from colorectal cancers (CRC). Methods: AE1/3 and BerEP4 expression was quantified using RPPA and immunohistochemistry (IHC) in formalin-fixed paraffinembedded tissues from 19 CRCs. For RPPA, samples were tested in sextuplicate. IHC was quantified by transforming images into positive/negative pixels using ImageJ. Results: In RPPA, the BerEP4 expression was greater than AE1/3 (p < 0.001). There was excellent precision with a mean coefficient of variation of 5.9% for AE1/3 and 6.9% for BerEP4. Expression of AE1/3 and BerEP4 showed significant correlation (p < 0.0001). For IHC, antibodies showed specific epithelial staining. There was no difference in intensity of expression but there were slight differences in extent of expression with, on average, 3.5% more AE1/3-positive pixels than BerEP4-positive pixels (p = 0.016). Antibody expression (number of positive pixels) showed significant correlation (p < 0.0001). Comparison of RPPA with IHC showed significant correlation for each antibody, (BerEP4: p = 0.044; AE1/3: p = 0.037). Combining markers (using the geometric mean) improved the correlation between the assays (p= 0.028). Conclusion: Expression of AE1/3 and BerEP4 correlate with each other in both RPPA and IHC. For each antibody, the two assays show significant correlation. Either antibody can be used to quantify tumour epithelium in RPPA with improved performance if markers are combined. Normalising RPPA data to “epithelial housekeepers” may improve biomarker data interpretation.

BerEP4 and AE1/3 are Reliable Markers of Epithelial Content for Biomarker Discovery Using Reverse Phase Protein Arrays (RPPA)