NTRK gene fusions are detected in both secretory and non-secretory breast cancers.

NTRK fusions represent a new biomarker-defined population that can be treated with TRK inhibitors. Although rare, NTRK fusions are detected across a wide range of solid tumors. Previous reports suggest that NTRK fusions are limited to the secretory subtype of breast cancer. Here we examined NTRK fusions in a large real world next-generation sequencing (NGS) dataset and confirmed secretory versus non-secretory status using H&E images. Of 23 NTRK fusion-positive cases, 11 were classified as secretory, 11 as non-secretory, and one as mixed status. The secretory subtype trended younger, was predominantly estrogen receptor (ER)-, had lower tumor mutational burden, and exhibited lower levels of genomic loss of heterozygosity. The non-secretory subtype was enriched for TP53 mutations. The secretory subtype was enriched for ETV6-NTRK3 fusions in 7 of 11 cases, and the non-secretory subtype had NTRK1 fusions in 7 of 11 cases, each with a different fusion partner. Our data suggests NTRK fusions are present in both secretory and non-secretory subtypes, and that comprehensive genomic profiling should be considered across all clinically advanced breast cancers to identify patients that could receive benefit from TRK inhibitors.

Expression and prognostic analysis of STAT6(YE361) in Hodgkin lymphoma.

This study aimed to investigate the expression and prognostic significance of the signal transducer and activator of transcription protein 6 (STAT6YE361) and EB virus encoding a small molecule RNA (EBER) in Hodgkin lymphoma (HL), as well as their correlation with clinical parameters. The expression of STAT6YE361 and EBER was investigated in HL via immunohistochemistry and in situ hybridization. Patient clinical data were retrospectively collected from archival libraries, and statistical analysis was performed. Overall, the nuclear positive expression rate of STAT6YE361 was 46%, and the EBER positive expression rate was 57%. STAT6YE361 was specifically expressed on the nucleus in cHL tissues. EBER was overexpressed in HL and had correlations with several clinical data, including age, gender, ethnicity, and primary cancer site. Interestingly, nuclear STAT6YE361 expression was correlated with EBER expression. Based on survival analysis, the nuclear expression of STAT6YE361 and female patients were associated with poor prognosis and were independent prognostic factors for five-year OS. These findings suggest that STAT6YE361 is a potential valuable index in the differential diagnosis and prognosis of HL. The mechanism of STAT6YE361 is related to Epstein-Barr virus infection.

Comparison of Her2/Neu Oncoprotein in Serum and Tissue Samples in Women with Breast Cancer.

BACKGROUND AND OBJECTIVES: Human Epidermal Growth Factor Receptor 2 (HER2/neu) is one of the most extensively studied proto-oncogens in breast cancer patients.  Accurate and timely assessment of the HER2/neu over expression is pivotal for the identification of breast cancer patients that could benefit from HER2-targeted therapy.  The present study was undertaken to investigate the diagnostic utility of serum HER2/neu testing by chemiluminescent immunoassay (CLIA) in breast cancer patients and compare it with the immunohistochemistry (IHC) method of HER2/neu expression. METHODS: Serum sample and tissue/paraffin block was collected from 52 patients with breast cancer before start of any anticancer regimen or hormonal therapy.  The tissue specimens were processed in Histopathology lab. Sections were immunostained with anti -estrogen receptor (ER) , anti -progesteron receptor (PR) and anti HER2/neu receptor  mouse monoclonal antibodies.) Serum HER2/neu was estimated using the chemiluminiscent immunoassay using 15ng/ml as the cut off. RESULTS: Out of 52 patients with breast cancer, serum HER2/neu was found elevated in 25(48.1%) patients and remaining 27(51.9%) showed normal serum HER2/neu concentrations. On IHC HER2/neu score was 3+ in 9(17.3%), 2+ in 10(19.2%), 1+ in 1(1.9%); while 32(61.5%) showed no HER2/neu expression.  31(59.6%) patients were ER positive and 28(53.8%) were PR positive. There was a significant correlation (P<0.001) of serum HER2 concentration with tissue expression of HER2/neu and Histological tumor grade. Serum HER2/neu levels showed a negative correlation with ER status (P=0.047) but no correlation with PR status. CONCLUSION: The result showed that the elevated serum HER2/neu was correlated with the IHC expression of HER2/neu in tissue and the histological grade of the tumor.  Findings suggest that post initial tissue diagnosis (IHC HER2/neu), serum HER2 assay may supplement subsequent tissue tests to monitor disease status and response to therapy.

Molecular subtyping of gastric cancer according to ACRG using immunohistochemistry - Correlation with clinical parameters.

BACKGROUND: Gastric cancer (GC) is a very heterogenous disease necessitating further stratification for prognostic and therapeutic aspects. Based on the recommendation of The Asisan Cancer Research Group (ACRG) recently established four molecular subtypes (MSI, MSS/EMT, MSS/TP53+, MSS/TP53-) which require molecular expression analysis. The technology required for comprehensive molecular analysis is expensive and not applicable for routine diagnostics. Thus, in this study we established a classification system utilizing immunohistochemistry and morphology-based analyses as surrogate markers in order to reproduce the ACRG molecular subtypes of gastric cancer. To clarify the clinical relevance of the novel classification system, we performed a correlation with established clinical parameters. METHODS: The study cohort consisted of 189 patients with GC (UICC III and IV). Using immunohistochemistry, the following markers were analysed: MLH1, MSH2, MSH6, PMS2 (as a surrogate for microsatellite status), p53, SOX9. We assessed tumor budding as a surrogate for EMT to distinguish between MSS/EMT and MSS/non-EMT groups. RESULTS: Immunohistochemical and morphologic subtyping classified cases as follows: 10% MSI, 35% MSS/EMT, 16% MSS/TP53 + and 39% MSS/TP53-. Subtypes significantly correlated with the Lauren classification, tumor stage, venous invasion and SOX9 expression (p < .05). There was no significant correlation between molecular subtype and lymph node growth pattern. CONCLUSION: We propose a simple algorithm for molecular subtyping of GC using universally available immunohistochemistry, which correlates with clinical parameters and is cost-effective and applicable in diagnostic routine. This classification might prospectively help to determine patient prognosis, optimize patient care and homogenize patient cohorts for clinical trials.

Distinct histologic and genetic characteristics of round cell sarcoma with CIC-DUX4 fusion and comparison with ewing sarcoma.

CIC-DUX4 fusion gene associated sarcoma is a new emerging subgroup of round cell sarcoma with Ewing sarcoma-like morphology. Distinguishing these tumors from Ewing sarcoma family tumors (ESFT) is critical because of the clinical impact but is still challenging due to the overlapped histological and immunohistochemical phenotypes of each subtype. The present study investigated small round cell sarcoma to identify CIC-DUX4 fusion positive sarcoma, examined clinical, histopathologic and immunohistochemical characteristics of CIC-DUX4 sarcoma, and evaluated parameters to differentiate Ewing sarcoma family tumors. Seventy patients with undifferentiated round cell sarcoma or Ewing-like sarcoma were retrieved. Molecular tests including EWSR1, CIC break apart FISH, and RT-PCR for CIC-DUX4 gene fusion were performed and immunohistochemistry was performed. Six cases (8.6%) of CIC-DUX4 sarcomas were detected. Histologically, CIC-DUX4 sarcomas composed of heterogeneous round, plasmacytoid, and spindle cells and more commonly showed cytologic pleomorphism with bizarre nuclei and multinucleated cells and myxoid stoma unlike ESFT. CIC-DUX4 sarcomas didn't show overall survival differences (p = 0.325) compared to ESFT but they demonstrated short disease-free survival (p = 0.034) and poor response to treatment (p = 0.007). Therefore, molecular analysis to detect the distinctive genetic alteration is mandatory in tumors with atypical histologic, immunohistochemical and/or clinical presentation for accurate diagnosis and treatment.

Immunohistochemical algorithms and gene expression profiling in primary cutaneous B-cell lymphoma.

OBJECTIVE: to assess whether immunohistochemical (IHC) algorithms used to classify the cell of origin (COO) of nodal Diffuse Large B-cell lymphoma (nDLBCL) in Germinal Center type (GCB) and non-GCB subtypes may be applied to Primary Cutaneous B-cell lymphoma (PCBCL) too, and which of these algorithms performs better on PCBCL. DESIGN: Retrospective case control study. SETTING: Pathology Department of the University Hospital "San Giovanni di Dio e Ruggi d'Aragona" Salerno, Italy. PARTICIPANTS: Fourteen PCBCL, including Primary Cutaneous follicle centre lymphoma (PCFCL) and primary cutaneous diffuse large B-cell lymphoma, Leg type (PCDLBCL-LT) and 14 nDLBCL were evaluated for 7-year period (January 2011 to December 2017). Primary cutaneous marginal zone cell lymphoma (PCMZL) cases were not included in the present study. INTERVENTION: Evaluation of immunohistochemical CD10, BCL6, MUM1/IRF4, BCL2, MYC and Ki-67 expression and classification according to three different algorithms. Gene expression profiling (GEP) was performed on the same series using Lymph2Cx assay (Nanostring). The data obtained were compared and analysed. RESULTS: All the IHC algorithms showed 13 GCB and 15 non-GCB. GEP showed 12 GCB, 12 activated B cell-type and 4 unclassified. CONCLUSIONS: The PCBCL were classifiable as GCB and non-GCB like the nDLBCL as IHC algorithms were concordant to GEP and produced the same results.

Malignant pleural mesothelioma with an EML4-ALK fusion: Expect the unexpected!

Case report of malignant pleural mesothelioma with an ALK gene rearrangement, detected by FISH and confirmed by RNA-based next-generation sequencing. The co-occurrence of ALK gene fusions with the more common genetic alterations in CDKN2A, NF2 and BAP1 has, to our best knowledge, not yet been described in malignant mesothelioma. Furthermore, this unexpected finding could suggest a potential target for therapy in this subset of malignant mesotheliomas.

MUM-1 immunohistochemistry has high accuracy and reliability in the diagnosis of chronic endometritis: a multi-centre comparative study with CD-138 immunostaining.

PURPOSE: The current gold standard for chronic endometritis (CE) diagnosis is immunohistochemistry (IHC) for CD-138. However, IHC for CD-138 is not exempt from diagnostic limitations. The aim of our study was to evaluate the reliability and accuracy of MUM-1 IHC, as compared with CD-138. METHODS: This is a multi-centre, retrospective, observational study, which included three tertiary hysteroscopic centres in university teaching hospitals. One hundred ninety-three consecutive women of reproductive age were referred to our hysteroscopy services due to infertility, recurrent miscarriage, abnormal uterine bleeding, endometrial polyps or myomas. All women underwent hysteroscopy plus endometrial biopsy. Endometrial samples were analysed through histology, CD138 and MUM-1 IHC. The primary outcome was to evaluate the diagnostic accuracy of MUM-1 IHC for CE, as compared with CD-138 IHC. RESULTS: Sensitivity and specificity of CD-138 and MUM-1 IHC were respectively 89.13%, 79.59% versus 93.48% and 85.03%. The overall diagnostic accuracy of MUM-1 and CD-138 IHC were similar (AUC = 0.893 vs AUC = 0.844). The intercorrelation coefficient for single measurements was high between the two techniques (ICC = 0.831, 0.761-0.881 95%CI). However, among CE positive women, MUM-1 allowed the identification of higher number of plasma cells/hpf than CD-138 (6.50 [SD 4.80] vs 5.05 [SD 3.37]; p = 0.017). Additionally, MUM-1 showed a higher inter-observer agreement as compared to CD-138. CONCLUSION: IHC for MUM-1 and CD-138 showed a similar accuracy for detecting endometrial stromal plasma cells. Notably, MUM-1 showed higher reliability in the paired comparison of the individual samples than CD-138. Thus, MUM-1 may represent a novel, promising add-on technique for the diagnosis of CE.

Correlation of manual semi-quantitative and automated quantitative Ki-67 proliferative index with OncotypeDXTM recurrence score in invasive breast carcinoma.

BACKGROUND: Ki-67 immunohistochemistry (IHC) staining is a widely used cancer proliferation assay; however, its limitations could be improved with automated scoring. The OncotypeDXTM Recurrence Score (ORS), which primarily evaluates cancer proliferation genes, is a prognostic indicator for breast cancer chemotherapy response; however, it is more expensive and slower than Ki-67. OBJECTIVE: To compare manual Ki-67 (mKi-67) with automated Ki-67 (aKi-67) algorithm results based on manually selected Ki-67 "hot spots" in breast cancer, and correlate both with ORS. METHODS: 105 invasive breast carcinoma cases from 100 patients at our institution (2011-2013) with available ORS were evaluated. Concordance was assessed via Cohen's Kappa (κ). RESULTS: 57/105 cases showed agreement between mKi-67 and aKi-67 (κ 0.31, 95% CI 0.18-0.45), with 41 cases overestimated by aKi-67. Concordance was higher when estimated on the same image (κ 0.53, 95% CI 0.37-0.69). Concordance between mKi-67 score and ORS was fair (κ 0.27, 95% CI 0.11-0.42), and concordance between aKi-67 and ORS was poor (κ 0.10, 95% CI -0.03-0.23). CONCLUSIONS: These results highlight the limits of Ki-67 algorithms that use manual "hot spot" selection. Due to suboptimal concordance, Ki-67 is likely most useful as a complement to, rather than a surrogate for ORS, regardless of scoring method.

Utility of a new notation to visualize flow cytometry analysis results: first preliminary comparison with immunohistochemistry to detect CD30 expression on T-cell lymphoma cells.

BACKGROUND: It is important to confirm CD30 expression in T-cell lymphoma cases, but immunohistochemical staining for CD30 is not commonly performed and no comparison has been done between the results of flow cytometry (FCM) and immunohistochemical staining for CD30. Therefore, we devised a notation that we termed proportion of immunoreactivity/expression for FCM (PRIME-F notation), based on the cellular proportion showing different antigen-antibody reactivity. METHODS: We retrospectively compiled 211 cases of T-cell lymphoma, assessed via FCM, from major hospitals in Miyagi Prefecture from January 2012 to January 2019, and compared 52 of these cases with the immunohistochemical immunoreactive (IR) pattern of CD30 (PRIME-I notation). The PRIME-F notation was divided into five levels: notations starting with "-" followed by 3, 2, and 1 ">" correspond to level-I, level-II, or level-III; notations starting with "(dim)+" correspond to level-IV; and those starting with "+" or "(bright)+" correspond to level-V. RESULTS: The 52 cases of PRIME-F notation with "+" included 16 cases of peripheral T-cell lymphoma (PTCL/NOS), 3 of follicular T-cell lymphoma (FTL), 3 of angioimmunoblastic T-cell lymphoma (AITL), 6 of extranodal NK/T-cell lymphoma/nasal type (ENKL), 18 of adult T-cell lymphoma (ATL), and 6 cases of anaplastic large cell lymphoma (ALCL). Eight of the 52 cases were immunohistochemically CD30-negative. In the PRIME-F level-I to III group (excluding false-positive cases), 21.7% (5 out of 23 cases) were < 10% positive for CD30 upon immunohistochemistry (IHC). Contrarily, in the level-IV & -V group, no CD30 positivity rate of < 10% upon IHC was found (0%) (p = 0.0497). In level-IV, 42.9% of cases presented a CD30 negative rate > 1/3 upon IHC, while in level-V, only 7.1% (one out of 14 cases) did. The CD30 negative rate tended to be low (p = 0.0877) in level-V. CONCLUSIONS: To our knowledge, this is the first report describing the correspondence between FCM and immunohistochemistry findings for CD30 through newly proposed notations. The PRIME-F and PRIME-I notations for CD30 showed a minor positive correlation. The PRIME notation is considered universally applicable to antibodies, and notations of both FCM and IHC show great potential for big data.

HER2 testing by immunohistochemistry in breast cancer: A multicenter proficiency ring study.

BACKGROUND: Human epidermal growth factor receptor 2 (HER2) over-expression in breast cancer is associated with aggressive tumor behavior and predicts response to targeted therapy. Accurate HER2 result is paramount for optimal patient management. However, routine HER2 immunohistochemistry (IHC) testing are subjected to intra- and inter-laboratory variability. OBJECTIVE: This study aims to determine inter-laboratory variation in HER2 IHC testing through a slide-exchange program between five main reference laboratories. METHOD: A total of 20 breast carcinoma cases with different known HER2 expression and gene status were selected by the central laboratory in five testing rounds. Three unstained tissue sections from each case were sent to participating laboratories, which immunostained and interpreted the HER2 immunohistochemistry result. One of the stained slides was sent to one designated participating laboratory for evaluation. Results were analyzed by the central laboratory. RESULTS: A complete concordance was achieved in six IHC-positive and six IHC-negative cases, its gene status of which was confirmed by in-situ-hybridization (ISH) study. The discordant results were observed in six equivocal cases, one negative case and one positive case with a concordance rate of 50-88.3%. Interestingly, the negative discordant case actually displays tumor heterogeneity. Good inter-observer agreement was achieved for all participating laboratories (k = 0.713-1.0). CONCLUSION: Standardization of HER2 testing method is important to achieve optimum inter-laboratory concordance. Discordant results were seen mainly in equivocal cases. Intra-tumoral heterogeneity may impact the final HER2 IHC scoring. The continuous quality evaluation is therefore paramount to achieve reliable HER2 results.

Applicability and interpretation of HER2/Neu & PD-L1 stains in gastrointestinal tract tumours.

The luminal gastrointestinal tract carcinomas are one of the major causes of cancer-related deaths. To improve overall survival, the current trend is to combine targeted therapeutic agents with conventional chemotherapies. Major trials have shown survival benefits with this approach and many more trials are being undertaken. However, pathologists often get perplexed by different methods of interpretation and reporting of these stains, vital for deciding therapeutic approaches.

Rate of Immunohistochemistry Utilization in the Diagnosis of Cutaneous Melanocytic Lesions.

ABSTRACT: Melanocytic lesions represent a large portion of the workload in many laboratories. Although many melanocytic nevi can be confidently diagnosed based on routine hematoxylin and eosin light microscopy, ancillary testing is often warranted. Various immunohistochemical (IHC) stains are routinely used in the diagnosis of melanocytic lesions. Because melanocytic lesions are frequently encountered in skin specimens, the use of IHC is likely to represent a significant area of resource utilization in dermatopathology laboratories. Our study investigates the rate of IHC utilization in the diagnosis of melanocytic lesions in a high-volume, government-funded, not-for-profit laboratory. Of the 1230 cases of melanocytic lesions investigated, including benign as well as malignant entities, 300 cases involved the utilization of IHC. IHC was used in a larger percentage of melanomas than nevi and in a larger percentage of melanoma in situ cases than invasive melanomas. SOX10 was overwhelmingly the most frequently used IHC.

Clinical significance of immunohistochemistry to detect BRAF V600E mutant protein in thyroid tissues.

ABSTRACT: This study investigated the feasibility of using immunohistochemistry (IHC) instead of PCR to detect BRAF V600E mutant protein in papillary thyroid carcinoma (PTC), and to determine the value of using preoperative BRAF V600E mutant protein by IHC to assist in the diagnosis of thyroid nodule patients with Hashimoto's thyroiditis (HT).The expression of BRAFV600E mutant protein was measured in 23 cases of HT+PTC, 31 cases of PTC, and 28 cases of HT by IHC, followed by PCR in the same samples for validation. SPSS 19.0 software was used for statistical analysis.The sensitivity and specificity of IHC to detect BRAF V600E mutation were 100% and 42.86%, respectively. In addition, the mutation rate of BRAF V600E protein in the HT+PTC group (34.78%, 8/23) was lower than that in the PTC group (80.65%, 25/31).The application of IHC to detect BRAF V600E mutant protein has good sensitivity but not specificity to diagnose PTC. IHC can be used as a preliminary screening method to detect BRAF V600E mutation. The strongly positive (+++) staining of IHC potently indicated BRAF V600E gene mutation. For suspicious thyroid nodules combined with HT, the detection of BRAF V600E mutant protein with IHC alone is not of great significance for differentiating benign and malignant nodules.

Glomerular C4d deposition in proliferative glomerular diseases.

INTRODUCTION: The aim of this study was to evaluate the immunohistochemical expression of C4d in native renal biopsies of proliferative glomerular diseases, complement pathways in these diseases, and assess the relationship of C4d with histological and clinicopathological parameters, other complement proteins, and immunoglobulin markers. METHODS: This cross-sectional study was conducted during the year 2018-19 involving 107 native renal biopsies with histologically diagnosed cases of proliferative glomerular diseases. C4d immunohistochemical evaluation of renal tissue sections was performed using polyclonal antihuman C4d as the primary antibody. Patients were classified as positive and negative groups based on their glomerular C4d deposition. RESULTS: The overall prevalence of C4d positivity was 80.4% in proliferative glomerular diseases ranging between 60.0% in C3 glomerulonephritis to 92.9% in membranoproliferative glomerulonephritis. Mixed capillary and mesangial deposition were noted in all cases of proliferative glomerulonephritis. Classical pathway was dominantly involved in all glomerular diseases except C3 glomerulonephritis and IgA nephropathy. Multivariate logistic regression analysis revealed that glomerular IgG staining (aOR: 5.86, 95% CI: 1.26-27.14) and IgM staining (aOR: 3.90, 95%CI: 1.07-14.18) were significantly associated with C4d positivity. CONCLUSION: C4d staining along with immunoglobulin markers such as IgG and IgM and complement proteins can be useful in delineating different complement activation pathways in glomerular diseases and understanding the disease pathogenesis.

Malignancy is in the eye of the beholder: Pathologic diagnosis of challenging follicular neoplasms in the era of noninvasive follicular thyroid neoplasms with papillary-like nuclear features and immunohistochemical and molecular adjuncts.

BACKGROUND: Classification of thyroid follicular neoplasms can be challenging for pathologists. Introduction of noninvasive follicular thyroid neoplasms with papillary-like nuclear features, the utilization of immunohistochemistry, and molecular analysis are all thought to be valuable diagnostic adjuncts. Our aim was to determine whether interobserver variability for follicular neoplasms has improved since the application of these adjuncts. METHODS: One representative section from a cohort of follicular neoplasms previously proven difficult for pathologists were examined independently by 7 pathologists and assigned to 1 of 3 diagnostic categories (benign, neoplasms with papillary-like nuclear features, or malignant). This process was carried out separately 3 times: (1) after viewing hematoxylin and eosin stain slides, (2) hematoxylin and eosin stain in conjunction with immunohistochemistry, and (3) hematoxylin and eosin stain/immunohistochemistry in conjunction with molecular analysis. The interobserver variability and overall agreement were then calculated using the free-marginal kappa coefficient. RESULTS: Agreement on hematoxylin and eosin stain was 57%, with a kappa coefficient of 0.36 (minimal agreement). The agreement improved slightly with the application of immunohistochemistry (kappa coefficient = 0.49 [weak agreement] and a percentage agreement 67%). The level of agreement decreased slightly after the addition of molecular analysis (kappa coefficient = 0.43 [weak agreement] and percentage agreement 62%). CONCLUSION: Despite attempts to standardize the diagnostic criteria for neoplasms with papillary-like nuclear features and the utilization immunohistochemistry and molecular analysis, attaining pathologic consensus for difficult follicular neoplasms of the thyroid remains a challenge.

Analysis of real-world PD-L1 IHC 28-8 and 22C3 pharmDx assay utilisation, turnaround times and analytical concordance across multiple tumour types.

AIMS: Programmed death-1/programmed death ligand 1 (PD-1/PD-L1) inhibitor therapy is accompanied by companion or complementary PD-L1 testing in some tumour types. We investigated utilisation of the Dako PD-L1 IHC 28-8 and 22C3 pharmDx assays and the Ventana PD-L1 (SP142) assay and evaluated concordance between the 28-8 and 22C3 assays in a real-world cohort of patients tested at a single US national reference laboratory. METHODS: NeoGenomics Laboratories performed PD-L1 testing on tumour samples between October 2015 and March 2018. PD-L1 test results were matched with patient characteristics using unique identifiers. Concordance between the 28-8 and 22C3 assays was evaluated in matched tumour samples. Data were evaluated across multiple tumour types and in subgroups of patients with lung cancer, melanoma, squamous cell carcinoma of the head and neck, and urothelial carcinoma. RESULTS: 62 180 individual PD-L1 tests were conducted on samples from 55 652 patients. PD-L1 test volume increased ~10-fold over the period evaluated. Test failure rates were typically low, and test turnaround time (TAT) ranged between 2 and 4 days. Concordance between the 28-8 and 22C3 assays was strong in the overall population and across tumour type subgroups (Kendall's tau correlations of 0.94 and 0.92-0.98, respectively). CONCLUSIONS: Test failure rates for PD-L1 tests were low and TAT remained reasonable despite marked increases in test volume. Concordance was high between the 28-8 and 22C3 assays across a range of tumour types and biopsy locations. These findings add to the literature showing high concordance between the 28-8 and 22C3 assays.

Comparison of Estrogen receptors, Progesterone receptors and HER2-neu immunohistochemistry results in breast cancer with those of Oncotype Dx.

Oncotype Dx (ODx) recurrence score (RS) is used in early breast cancer to guide the use of adjuvant therapy. In addition to RS the test produces results of reverse transcriptase-polymerase chain reaction (RT-PCR) of Estrogen receptors (ER), Progesterone receptors (PgR) and Human epidermal growth factor receptor 2 (HER2-neu). Our goal was to determine the correlation between immunohistochemistry (IHC) and RT-PCR testing of ER, PgR and HER2-neu and to correlate the results of ODx RS with tumors' grade, age and PgR status. 113 patients with ER+, HER2-neu- breast cancers that underwent ODx testing were analyzed for receptors correlation and concordance rates by the 2 methods. A total of 104 patients had ER+/PgR+ tumors and 9 patients had ER+/PgR- tumors by IHC, the average RS were 17.5 ± 9.1 and 31.2 ± 8.7 (P < 0.001) respectively. The Spearman correlation coefficient between IHC and ODx results were 0.5 (95% CI 0.34-0.62) for ER and 0.78 (95% CI 0.7-0.84) for PgR. The concordance rate between IHC and ODx was 98.2% for ER, 89.4%.for PgR and 99.1% for HER2-neu. Most of the discordant cases (9 out of 13) were low positive (1-10%) by IHC and negative by RT-PCR. In addition higher tumor grade was associated with a higher ODx RS. Our data show that the IHC results were highly concordant with RT-PCR for ER, PgR and Her2-neu. In addition low positive (1-10%) ER/PgR might indicate a real negative status. Our study shows that ER+/PgR- breast cancers are associated with a significantly higher ODx RS.