Immunohistochemical versus molecular (BluePrint and MammaPrint) subtyping of breast carcinoma. Outcome results from the EORTC 10041/BIG 3-04 MINDACT trial.

PURPOSE: This study compares immunohistochemical (IHC) versus molecular subtyping (BluePrint and MammaPrint) in the population of patients enrolled in MINDACT and outcome based on molecular subtyping (MS) versus surrogate pathological subtyping (PS) as defined by the 2013 St. Gallen guidelines. METHODS: MS classified patients in the following subtypes: Luminal A, Luminal B, HER-2-, and Basal-type. IHC/FISH for pathological subtyping (ER, PgR, HER-2, and Ki67) was centrally assessed in the European Institute of Oncology (n = 5806). Hazard ratios for distant-metastasis-free survival (DMFS) by subtype were adjusted for chemotherapy and endocrine therapy administration and thus independent of adjuvant treatment allocation. RESULTS: PS Luminal cancers classified as HER-2+ or Basal-type by MS did not have a significantly lower DMFS than the Luminal-type cancers by MS (95.9%): HR = 1.40, 95% CI 0.75-2.60 (p = 0.294). More patients were identified with Luminal A disease by MS (63%) as compared with PS (47%) with comparable 5-year DMFS (≥96.0%). Among the 500 patients with PS TN cancers, MS identified 24 (5%) patients as Luminal-type with 5-year DMFS estimated at 100% versus 71.4% for MS HER-2+ or 90.1% for MS Basal-type. CONCLUSIONS: MS was able to re-stratify 54% of patients with a Luminal-B PS subtype to a low-risk Luminal A-type group with comparable outcome. Among TN EBC, 5% were classified as Luminal by MS with Luminal-like outcome. Molecular classification can help to identify a larger group of patients with low risk of recurrence compared with the more contemporarily used classification methodology including high-quality assessed Ki67.

High concordance of protein (by IHC), gene (by FISH; HER2 only), and microarray readout (by TargetPrint) of ER, PgR, and HER2: results from the EORTC 10041/BIG 03-04 MINDACT trial.

BACKGROUND: To investigate the correlation of TargetPrint with local and central immunohistochemistry/fluorescence in situ hybridization assessment of estrogen (ER), progesterone (PgR), and human epidermal growth factor receptor 2 (HER2) in the first 800 patients enrolled in the MINDACT trial. PATIENTS AND METHODS: Data from local (N = 800) and central (N = 626) assessments of receptor status were collected and compared with TargetPrint results. RESULTS: For ER, the positive agreement (the percentage of central pathology positive assessments that were also TargetPrint/local laboratory positive) for TargetPrint in comparison to centralized assessment was 98% with a negative agreement (the percentage of central pathology negative assessments that were also TargetPrint/local laboratory negative) of 96%. For PgR, the positive agreement was 83% with a negative agreement of 92%. For HER2, the positive agreement was 75% with a negative agreement of 99%. Even though the local assessment showed higher positive agreement for PgR (89%) and higher positive agreement for HER2 (85%), the range of discordant local versus central assessments were as high as 6.7% for ER, 12.9% for PgR, and 4.3% for HER2. CONCLUSION: TargetPrint and local assessment of ER, PgR, and HER2 show high concordance with central assessment in the first 800 MINDACT patients. However, there are concerns about the higher discordance rates for some local sites. TargetPrint can improve the reliability of hormone receptor and HER2 testing for those centers with a lower rate of concordance with the reference laboratory, with the limitation of a positive agreement of 75% for HER2. TargetPrint consequently has important implications for treatment decisions in clinical practice and is a reliable alternative to local assessment for ER. CLINICAL TRIALS NUMBER: NCT00433589.

[Comparing immunohistochemical diagnosis of cancer of unknown primary with gene expression-based tumor classification]. / Vergleich immunhistologischer mit genexpressionsbasierter Diagnostik: von Karzinomen mit unbekanntem Primarius.

Five percent of cancer cases present as metastases. If the primary tumor cannot be identified after diagnostic workup, the disease is referred to as cancer of unknown primary (CUP) and is classified as C80.9 according to ICD-10. In Germany, CUP is among the ten most common causes of tumor-related death, with mortality similar to mortality in gastric or pancreatic cancer. Biopsies of the tumor manifestation are generally examined histopathologically and by immunohistochemistry (IHC). Gene expression profiling (GEP) is a new diagnostic technique that might further contribute to tumor specification.In a retrospective study, 43 CUP cases underwent central immunohistochemical review and centrally performed GEP using a classifier based on 495 genes. There was concordance between IHC, GEP and clinical picture in 54% of cases. In four cases, the combination of methods led to an unequivocal identification of the primary tumor.In conclusion, we regard detailed IHC workup and complementary GEP advisable for the purposes of targeted therapy, as well as to identify or exclude specific tumors in a CUP situation.

European inter-institutional impact study of MammaPrint.

AIM: To measure the impact of MammaPrint on adjuvant treatment decisions and to analyze the agreement in treatment decisions between hospitals from 4 European countries for the same patient cohort. METHODS: Breast cancer patients were prospectively enrolled and MammaPrint was assessed. Patients' clinical data without and then with MammaPrint results were sent to the different multidisciplinary teams and treatment advice was provided for each patient. RESULTS: Using MammaPrint, chemotherapy treatment advice for ER+/HER2- breast cancer patients was changed in 37% of patients by the Dutch, 24% by the Belgian, 28% by the Italian and 35% by the Spanish teams. MammaPrint increased the inter-institutional agreement in treatment advice (chemotherapy or no chemotherapy) from 51% to 75%. CONCLUSION: The results of this study indicate that MammaPrint impacts adjuvant chemotherapy recommendation. MammaPrint can decrease inter-institutional and inter-country variability in adjuvant treatment advice for breast cancer patients.