Diagnostic Value of Mutation-Specific Antibodies for Immunohistochemical Detection of Epidermal Growth Factor Receptor Mutations in Non-Small Cell Lung Cancer: A Meta-Analysis

<div><p>Background</p><p>Various studies have assessed the diagnostic accuracy of EGFR mutation-specific antibodies in non-small cell lung cancer (NSCLC). We performed a meta-analysis of existing data to investigate the diagnostic value of mutation-specific antibodies for detection of EGFR mutations in NSCLC.</p><p>Methods</p><p>We systematically retrieved relevant studies from PubMed, Web of Knowledge, and Google Scholar. Data from studies that met the inclusion criteria were extracted for further exploration of heterogeneity, including calculation of the average sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and analysis of SROC(summary receiver operating characteristic) curves.</p><p>Results</p><p>Fifteen studies met our inclusion criteria. A summary of the meta-analysis of the efficacy of the anti-E746-A750 antibody was as follows: sensitivity, 0.60 (95% CI, 0.55–0.64); specificity, 0.98 (95% CI, 0.97–0.98); PLR, 33.50 (95% CI, 13.96–80.39); NLR, 0.39 (95% CI, 0.30–0.51) and DOR, 111.17 (95% CI, 62.22–198.63). A similar meta-analysis was performed for the anti-L858R antibody with results as follows: sensitivity, 0.76 (95% CI, 0.71–0.79); specificity, 0.96 (95% CI, 0.95–0.97); PLR, 24.42 (95% CI, 11.66–51.17); NLR, 0.22 (95% CI, 0.12–0.39) and DOR, 126.66 (95% CI, 54.60–293.82).</p><p>Conclusion</p><p>Immunohistochemistry alone is sufficient for the detection of EGFR mutations if the result is positive. Molecular-based analyses are necessary only if the anti-E746-A750 antibody results are negative. Immunohistochemistry seems more suitable for clinical screening for EGFR mutations prior to molecular-based analysis.</p></div

Flow diagram of study selection by using electronic database.

<p>Flow diagram of study selection by using electronic database.</p

Forest plots for sensitivity (A) and specificity (B) of the anti-E746-A750 antibody in the detecting the EGFR exon 19 deletion.

<p>Sensitivity  = 0.60 (95% CI, 0.55–0.64); specificity  = 0.98 (95% CI, 0.97–0.98).</p

Weighted meta-regression analysis of the effects of methodological and study design on diagnostic value of mutation-specific antibodies.

<p>Abbreviations: PDOR, pooled diagnostic odds ratio; CI, confidence interval; STARD, the Standards for Reporting Diagnostic accuracy; QUADAS, the Quality Assessment of Diagnostic Accuracy Studies; IHC, immunohistochemistry.</p><p>Weighted meta-regression analysis of the effects of methodological and study design on diagnostic value of mutation-specific antibodies.</p

Characteristics of included studies.

<p>Abbreviations: FFPE, formalin-fixed paraffin-embedded; MFPE, methanol-fixed paraffin-embedded; STARD, the Standards for Reporting Diagnostic accuracy, QUADAS, the Quality Assessment of Diagnostic Accuracy Studies.</p><p>Characteristics of included studies.</p

Summary receiver operating characteristic (SROC) curve for the anti-E746-A750 antibody (A) and the anti-L858R antibody (B) in the diagnosis of EGFR mutation in the 15 included studies.

<p>The anti-E746-A750 antibody: AUC = 0.97, Q* = 0.92; the anti-L858R antibody: AUC = 0.98, Q* = 0.94.</p

The funnel plot of publication bias for the anti-E746-A750 antibody (A) and the anti-L858R antibody (B).

<p>There was no significant publication bias (the anti-E746-A750 antibody, P = 0.93; the anti-L858R antibody, P = 0.85).</p

Forest plots for sensitivity (C) and specificity (D) of the anti-L858R antibody in the detecting the EGFR exon 21 mutation.

<p>Sensitivity  = 0.76 (95% CI, 0.71–0.79); specificity  = 0.96 (95% CI, 0.95–0.97).</p

Summary of included studies.

a<p>The visual score criteria consider 1+ or more staining as positive.</p>b<p>The visual score criteria consider 2+ or 3+ staining as positive.</p>c<p>Q score was calculated by multiplying the percentage (P, 0–100%) of positive cells by the intensity (I, 0–3) of staining (Q = P*I; maximum  = 300) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0105940#pone.0105940-Kozu1" target="_blank">[30]</a>.</p>d<p>H score criteria assessed staining intensity (I, 0–4) multiplied by the percentage (P, 0–100%) of positive cells for each intensity for a final IHC score (H = P*I; maximum  = 400) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0105940#pone.0105940-Kato1" target="_blank">[27]</a>.</p><p>Abbreviations: IHC, immunohistochemistry; TMA, tissue microarray; AUC, the best area under the ROC curves; TP, true positive; FP, false positive; FN, false negative; TN, true negative; PCR-RFLP, Polymerase chain reaction-restriction fragment length polymorphism; HRMA, high resolution melting analysis.</p><p>Summary of included studies.</p

Forest plot for the positive likelihood ratio (PLR) (A), the negative likelihood ratio (NLR) (B) and the diagnostic odds ratio (DOR) (C) of the anti-E746-A750 antibody.

<p>PLR (positive likelihood ratio)  = 33.50 (95% CI, 13.96–80.39); NLR (negative likelihood ratio)  = 0.39 (95% CI, 0.30–0.51); DOR (diagnostic odds ratio)  = 111.17 (95% CI, 62.22–198.63).</p