Journal Article

Comparison of immunohistochemistry with PCR for assessment of ER, PR, and Ki-67 and prediction of pathological complete response in breast cancer

Sinn, Hans-Peter, Seitz, Julia, Marmé, Frederik, Altevogt, Peter, Schneeweiss, Andreas, Schlombs, Kornelia, Veltrup, Elke, Lakis, Sotirios, Wirtz, Ralph M., Keller, Marius, Eidt, Sebastian, Laible, Mark

2017

Overview

Background Proliferation may predict response to neoadjuvant therapy of breast cancer and is commonly assessed by manual scoring of slides stained by immunohistochemistry (IHC) for Ki-67 similar to ER and PgR. This method carries significant intra- and inter-observer variability. Automatic scoring of Ki-67 with digital image analysis (qIHC) or assessment of MKI67 gene expression with RT-qPCR may improve diagnostic accuracy. Methods Ki-67 IHC visual assessment was compared to the IHC nuclear tool (AperioTM) on core biopsies from a randomized neoadjuvant clinical trial. Expression of ESR1, PGR and MKI67 by RT-qPCR was performed on RNA extracted from the same formalin-fixed paraffin-embedded tissue. Concordance between the three methods (vIHC, qIHC and RT-qPCR) was assessed for all 3 markers. The potential of Ki-67 IHC and RT-qPCR to predict pathological complete response (pCR) was evaluated using ROC analysis and non-parametric Mann-Whitney Test. Results Correlation between methods (qIHC versus RT-qPCR) was high for ER and PgR (spearman´s r  = 0.82, p  < 0.0001 and r  = 0.86, p  < 0.0001, respectively) resulting in high levels of concordance using predefined cut-offs. When comparing qIHC of ER and PgR with RT-qPCR of ESR1 and PGR the overall agreement was 96.6 and 91.4%, respectively, while overall agreement of visual IHC with RT-qPCR was slightly lower for ER/ESR1 and PR/PGR (91.2 and 92.9%, respectively). In contrast, only a moderate correlation was observed between qIHC and RT-qPCR continuous data for Ki-67/MKI67 (Spearman’s r  = 0.50, p  = 0.0001). Up to now no predictive cut-off for Ki-67 assessment by IHC has been established to predict response to neoadjuvant chemotherapy. Setting the desired sensitivity at 100%, specificity for the prediction of pCR (ypT0ypN0) was significantly higher for mRNA than for protein (68.9% vs. 22.2%). Moreover, the proliferation levels in patients achieving a pCR versus not differed significantly using MKI67 RNA expression (Mann-Whitney p  = 0.002), but not with qIHC of Ki-67 (Mann-Whitney p  = 0.097) or vIHC of Ki-67 ( p  = 0.131). Conclusion Digital image analysis can successfully be implemented for assessing ER, PR and Ki-67. IHC for ER and PR reveals high concordance with RT-qPCR. However, RT-qPCR displays a broader dynamic range and higher sensitivity than IHC. Moreover, correlation between Ki-67 qIHC and RT-qPCR is only moderate and RT-qPCR with MammaTyper® outperforms qIHC in predicting pCR. Both methods yield improvements to error-prone manual scoring of Ki-67. However, RT-qPCR was significantly more specific.

• Publisher: BioMed Central,Springer Nature B.V
• Subject: Antineoplastic Combined Chemotherapy Protocols - therapeutic use / Automation / Biomarkers / Biomedical and Life Sciences / Biomedicine / Breast cancer / Breast Neoplasms - drug therapy / Breast Neoplasms - genetics / Breast Neoplasms - metabolism / Breast Neoplasms - pathology / Cancer Research / Carcinoma, Ductal, Breast - drug therapy / Carcinoma, Ductal, Breast - genetics / Carcinoma, Ductal, Breast - metabolism / Carcinoma, Ductal, Breast - pathology / Carcinoma, Lobular - drug therapy / Carcinoma, Lobular - genetics / Carcinoma, Lobular - metabolism / Carcinoma, Lobular - pathology / Clinical medicine / Clinical Trials, Phase II as Topic / Estrogens / Female / Gene expression / Health Promotion and Disease Prevention / Humans / Immunoenzyme Techniques / Ki-67 Antigen - genetics / Ki-67 Antigen - metabolism / Medicine/Public Health / Neoadjuvant Therapy / Neoplasm Grading / Neoplasm Staging / Oncology / Patients / Prognosis / Randomized Controlled Trials as Topic / Real-Time Polymerase Chain Reaction / Receptor, ErbB-2 - genetics / Receptor, ErbB-2 - metabolism / Receptors, Estrogen - genetics / Receptors, Estrogen - metabolism / Receptors, Progesterone - genetics / Receptors, Progesterone - metabolism / Research Article / RNA, Messenger - genetics / ROC Curve / Surgical Oncology / Translational oncology / Tumors