Dicer expression in estrogen receptor-positive versus triple-negative breast cancer: an antibody comparison.
Dicer is an RNase III enzyme responsible for cleaving double-stranded RNAs into small interfering RNAs and microRNAs, which either target messenger RNA transcripts for degradation or inhibit translation. Dicer protein levels have been examined in breast cancer with contradictory results. Our goal was to resolve whether Dicer levels differ in breast cancer versus normal breast epithelium and between estrogen receptor-α-positive (ER+) or estrogen receptor-α-negative (ER-) primary breast cancers. We compared 3 different Dicer antibodies: Abcam 4A6, Abcam ab5818, and Sigma HPA000694, using immunohistochemistry and Western blot analyses. All 3 Dicer antibodies detected higher levels of Dicer in ER+ breast cancer cell lines versus ER-, and all 3 recognized exogenous overexpressed Dicer. In clinical specimens, all 3 antibodies detected higher Dicer in ER+ breast cancers versus triple-negative breast cancer (TNBC) but had very different staining patterns by immunohistochemistry on the same tumor samples. Using the optimal antibody, ab5818, selected for its sensitivity and specificity, Dicer protein expression was significantly higher in ER+ versus TNBC clinical specimens of primary tumor (P<.0001, unpaired t test). Dicer was also significantly higher in adjacent normal breast epithelium versus TNBC (P<.0001, paired t test; n=18 pairs). Differences in antibody performance may explain contrasting results observed in the literature regarding Dicer protein in breast cancer. If Dicer becomes more clinically relevant as a prognostic indicator, further antibody optimization and standardization will be critical.
Department of Pathology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045.
Nicole S
NS
Spoelstra
Department of Pathology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045.
Diana M
DM
Cittelly
Department of Pathology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045.
Jessica L
JL
Christenson
Department of Pathology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045.
Michael A
MA
Gordon
Division of Oncology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045.
Anthony
A
Elias
Department of Pathology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045.
Paul
P
Jedlicka
Department of Pathology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045. Electronic address: Jennifer.Richer@ucdenver.edu.
Jennifer K
JK
Richer
D000328:Adult; D000368:Aged; D000818:Animals; D000906:Antibodies / Q000276:immunology*; D000918:Antibody Specificity; D014408:Biomarkers, Tumor / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D001943:Breast Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000276:immunology / Q000473:pathology; D045744:Cell Line, Tumor; D053487:DEAD-box RNA Helicases / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D005260:Female; D057809:HEK293 Cells; D006801:Humans; D007150:Immunohistochemistry; D051379:Mice; D008875:Middle Aged; D011237:Predictive Value of Tests; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis; D011960:Receptors, Estrogen / Q000032:analysis*; D011980:Receptors, Progesterone / Q000032:analysis; D015203:Reproducibility of Results; D043244:Ribonuclease III / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D064726:Triple Negative Breast Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000276:immunology / Q000473:pathology; D015854:Up-Regulation; D055815:Young Adult
D000906:Antibodies; D014408:Biomarkers, Tumor; D053487:DEAD-box RNA Helicases; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D043244:Ribonuclease III; C508053:ERBB2 protein, human; C408087:DICER1 protein, human
Breast cancer; Dicer; Estrogen receptor; Immunohistochemistry; TNBC