Neuroendokrine Neoplasien (NEN) der Mamma sind spezifische Tumorentitäten. Ihre Häufigkeit wird in der Literatur mit bis zu 5 % der malignen epithelialen Neoplasien der Mamma angegeben. Definiert sind NEN der Mamma durch eine neuroendokrine Zytologie und Architektur, kombiniert mit der Expression der neurosekretorischen Vesikelproteine Chromogranin A und/oder Synaptophysin. Die Diagnose wird ergänzt durch die Angabe der proliferativen Aktivität und des Rezeptorstatus. Bei den NEN der Mamma handelt es sich nach Nomenklatur der WHO von 2012 1) um invasive neuroendokrin differenzierte Mammakarzinome, 2) um hochdifferenzierte neuroendokrine Tumoren (NET) oder 3) um gering differenzierte kleinzellige neuroendokrine Karzinome (NEC). Die vorliegende Übersichtsarbeit konzentriert sich auf 1) die Definition und Grundlagen der Diagnostik, 2) die Historie, Nomenklatur und die WHO-Klassifikationen von 2003 und 2012, 3) die Häufigkeit von NEN der Mamma, 4) den hereditären Hintergrund und die funktionelle Aktivität, 5) die Expression von Rezeptoren und 6) die möglichen klinischen Implikationen. Darüber hinaus werden erste Ergebnisse einer retrospektiv angelegten Studie (465 Patientinnen mit Mammakarzinom; Zeitraum 4 Jahre) zur Häufigkeit von NEN der Mamma am Brustzentrum des Universitätsklinikums Düsseldorf vorgestellt. Die Häufigkeit von NEN der Mamma lag hier bei 4,5 % (bei einem zugrundeliegenden diagnostischen Grenzwert von > 50 % Chromogranin-A- und/oder Synaptophysin-positiven Tumorzellen).

536 Background: The PRIME study (Douillard et al. New Engl. J. Med. 2014) demonstrated that testing all coding exons of both KRAS and NRAS proto-oncogenes (all-RAS) predicted response for anti-EGFR targeting antibody panitumumab better than testing only KRAS exon 2 (PFS: 8.9 vs 9.6 mo, OS: 20.2 vs. 26 mo). Thus, the EMA changed the label of this drug for Europe. Now all RAS testing has to be done on a high quality level. Therefore, an improved quality assurance (QA) system was developed. Methods: The German RAS Advisory Board as part of QuIP (Quality initiative Pathology) launched ring-trials to assure quality of RAS mutation detection. 12 test cases of metastatic colorectal cancers (mCRC) containing WT or mutated sequences in one of the three coding exons 2 – 4 of either the KRAS or the NRAS oncogenes. Additionally many QA passed participants supplied the results of all-RAS testing of mCRC for one year resulting in a RAS monitor. Results: In less than half a year an area-wide coverage of quality certified all-RAS testing laboratories was reached. In three ring-trials 89 of 93 (96%) institutions for pathology passed the QA using Sanger-Sequencing (60%), pyrosequencing (25%) or the COBAS system (15%). None of the methods was superior to another as comparable amounts of methods passed or failed the ring trials. As only 12 cases were tested the result is reliable with a lower limit of confidence of only 0.7. Thus, a RAS monitor was introduced as an additional instrument of QA. Here, the results of almost 4000 cases of mCRC tested for all-RAS were collected indicating RAS mutations in 45.7% of investigated cases (KRAS: 41.5%, NRAS: 4.2%). Conclusions: Ring-trials are a versatile tool to establish a network of quality tested diagnostic laboratories in a short time. In parallel data sets for benchmarking the frequencies of RAS mutations were generated region specifically. Thereby quality was brought to a higher level than without the RAS monitor.

Die wichtigsten, für das metastasierte kolorektale Karzinom (mKRK) bislang zugelassenen zielgerichteten Substanzen sind Cetuximab (Erbitux®) und Panitumumab (Vectibix®), beides Antikörper gegen den „epidermal growth factor receptor“ (EGFR oder ErbB1, Anti-EGFR-Klasse). Für beide Substanzen galt bis Mitte 2013, dass vor der Therapie der Mutationsstatus im Exon 2 des Onkogens Kirsten-RAS (KRAS Exon 2) analysiert werden musste, da eine Mutation in diesem Exon als negativer prädiktiver Marker für ein Ansprechen auf die Therapie identifiziert worden war. Daraus folgte, dass nur Tumoren ohne Mutation (Wildtyp, WT) mit Anti-EGFR-Klasse-Antikörpern behandelt werden durften. Aktuell wurden die Patienten aus den Zulassungsstudien auch auf Mutationen in den anderen Exons der KRAS- und NRAS-Onkogene untersucht. Daraus ergaben sich neue Erkenntnisse.

Die wichtigsten, für das metastasierte kolorektale Karzinom (mKRK) bislang zugelassenen zielgerichteten Substanzen sind Cetuximab (Erbitux®) und Panitumumab (Vectibix®), beides Antikörper gegen den „epidermal growth factor receptor“ (EGFR oder ErbB1, Anti-EGFR-Klasse). Für beide Substanzen galt bis Mitte 2013, dass vor der Therapie der Mutationsstatus im Exon 2 des Onkogens Kirsten-RAS (KRAS Exon 2) analysiert werden musste, da eine Mutation in diesem Exon als negativer prädiktiver Marker für ein Ansprechen auf die Therapie identifiziert worden war. Daraus folgte, dass nur Tumoren ohne Mutation (Wildtyp, WT) mit Anti-EGFR-Klasse-Antikörpern behandelt werden durften. Aktuell wurden die Patienten aus den Zulassungsstudien auch auf Mutationen in den anderen Exons der KRAS- und NRAS-Onkogene untersucht. Daraus ergaben sich neue Erkenntnisse.

The most important targeted substances approved for metastasized colorectal cancer are cetuximab (ErbituxA (R)) and panitumumab (VectibixA (R)), both of which are antibodies against epidermal growth factor receptor (EGFR or ErbB1) of the anti-EGFR class. For both substances up to the middle of 2013, the mutation status of the oncogene Kirsten-RAS (KRAS-exon 2) had to be analyzed before treatment, because a mutation in this exon had been identified as a negative predictive marker for response to therapy. Therefore, only non-mutated (wild type) tumors could be treated with antibodies of the anti-EGFR class.On the basis of these data the European Medicines Agency (EMA) as the European approval committee, authorized the therapeutic use of the antibody panitumumab in Summer 2013 and cetuximab in November 2013 exclusively for patients with tumors which tested negative for a mutation in exons 2-4 of the KRAS gene and exons 2-4 of the NRAS gene. The absence of mutations identifies the RAS wild type constellation so that patients with metastastic colorectal cancercan be treated with these substances. Because the mutation analysis must be carried out on histologically characterized tumor tissue, pathology plays a central role in the extended RAS mutation analysis and therefore the prediction of therapy response. In the meantime the patients of the approval studies were also investigated for mutations in the other exons of the KRAS and the NRAS oncogen. This resulted in new findings.Pathology in Germany provides a comprehensive and guaranteed molecular analysis procedure which fulfils all the requirements of the licensing authorities regarding quality assurance for the use of antibodies of the anti-EGFR class.

Neuroendocrine neoplasms (NEN) of the distal jejunum and ileum derive from serotonin-producing enterochromaffin (EC) cells. Due to their low proliferation rate and their infiltrative growth, they are often discovered at an advanced disease stage when metastasis has already occurred. The biology of these tumours is different from other NEN of the digestive tract. In order to standardise and improve diagnosis and therapy, the guidelines for the diagnosis and clinical management of jejuno-ileal NEN as well as for the management of patients with liver and other distant metastases from NEN were revised by the European Neuroendocrine Tumour Society (ENETS) in 2012. This review focuses on aspects relevant for surgical pathology.

e14016 Background: One option in the therapy of metastatic colorectal cancer (mCRC) is the targeting of the epidermal growth factor receptor (EGFR) using the antibodies panitumumab or cetuximab. Here, a biomarker, the KRAS gene, allows the prediction of the response on an individual basis as mutated forms of KRAS lead to a deregulation of the EGFR- signaling pathway by which the antibodies become useless. Therefore, the approval of the European Medicines Agency (EMEA) as well as a recommendation by the Food and Drug Administration (FDA) included that anti-EGFR targeted therapy is only valid in case of mCRCs with wildtypic (WT) KRAS sequences. Thus, the correct determination of the sequence of the KRAS oncogene became an important piece of work in the targeted therapy of mCRCs. Methods: Therefore, the German Society for Pathology (DGP) and the Federation of the German Pathologists (BDP) initiated under the umbrella of the Quality Initiative in Pathology (QuIP) a quality assurance (QA) system based on the testing of histological sections of 10 cases of mCRC. Two parameters were defined for passing the QA test: 1) Correctness or quality of the results independent of the applied testing method (table). 2) Time to completion (14 days). Results: 159 institutions for pathology participated in this QA system in the last two years resulting in a network of now 82 institutions in Germany that analyze the mutational status of the KRAS gene fast and with a high grade of quality. This was interestingly independent of the applied method (table-some institutes participated repeatedly). Conclusions: The results and consequences of the German QA system are presented here. Method No. of participants Sensitivity(true positives) Specificity(true negatives) ARMS-PCR 24 0.99 1.00 DHPLC 0 0.99 1.00 Didesoxy-sequencing 75 0.93 0.99 Hybridization 11 0.93 0.99 Melting point analysis 7 1.00 1.00 Other 7 0.97 1.00 Pyrosequencing 21 0.99 1.00 Restriction-fragment-length-polymorphism 3 0.93 0.93 Snapshot 1 1.00 1.00 Single strand conformational polymorphism 2 1.00 1.00 All 151 0.96 0.99 Author Disclosure Employment or Leadership Position Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Amgen, Merck Serono Amgen, Merck Serono

4018 Background: In the beginning of 2008 the EMEA (European Medicines Agency) approved with panitumumab for the first time an EGFR (epidermal growth factor receptor) targeting therapy for patients with metastatic colorectal cancer overexpressing the EGFR and showing wildtypic sequences in the KRAS gene as a predictive biomarker. Thus, the need for assuring the quality of laboratories emerged. The German Society for Pathology in cooperation with the Federation of the German Pathologist supported by an unrestricted financial grant of Amgen Germany arranged a quality assurance system (QAS). In this context two round- robin tests were carried out which results are presented here. METHODS Collection of results from two round -robin tests and their statistical analysis applying binary classification tests. RESULTS Test sets of 4 histological sections from ten different cases of colorectal tumors with known mutational status of the KRAS gene were prepared for the round-robin tests. The method for the mutation detection was unrestricted. A total of 74 participants from universities (44 - 59.5 %) or other institutions (30 - 40.5 %) attended the tests. 11 participants (14.8 %) failed the test (6 universities: 13.6 %, 5 institutions: 16.6 %). For the analysis didesoxy-sequencing (DDS: 55 - 66.2 %), ARMS®-PCR (8 - 10.4 %), melting-point analysis (MPA: 7 - 9.1 %), pyrosequencing (PS: 6 - 7.8 %), hybridization (HYB: 4 - 5.2 %), or SSCP (1 - 1.3 %) were used, in which some participants (3) used more than one method. It turned out that all methods employed for the testing gave similar results when comparing the rate of correct or wrong hits or the rate of false positive detection: DDS (0.92, 0.07, 0.02), ARMS®-PCR (0.91, 0.08, 0.05), MPA (0.94, 0.06, 0.04), PS (0.95, 0.05, 0.03) or HYB (0.90, 0.10, 0.08). CONCLUSIONS The quality of the molecular-pathological detection of KRAS mutations as precondition for an EGFR targeted therapy should be tested since about 15 % of laboratories did not meet a sufficient grade. For the mutation detection no method seemed superior. [Table: see text].

Prediction of the response of malignant tumors to target-oriented drugs plays an ever-increasing role in current cancer treatment. This means that prior to therapy the target molecule or its activity must be detected by molecular pathologic methods in tumor tissue by the pathologist. This has now been established for metastasised colorectal carcinomas (mCRC) since the beginning of 2008. In cases of planned therapy with the newly approved anti-EGFR antibody panitumumab (Vectibix (R)), it must first be investigated whether a mutation in the Kirsten-RAS (K-RAS) oncogene, and therefore permanent activation, or the wild-type is present before administration. This investigation is carried out on formalin-fixed paraffin-em bedded tissue from the pathology department and should be performed preferentially by institutes with experience in quality-controlled molecular diagnostic. The investigation is strictly stipulated on the instructions of the licensing authorities because this therapy is only justified in the presence of the wild-type.

The postoperative course of 44 patients (24 women, 20 men; mean age 31.5 [18-63] years) treated by ileocaecal resection for Crohn's disease was investigated prospectively. None of the patients received any prophylactic drug treatment during the 12-month postoperative period of observation. Recurrence of Crohn's disease was endoscopically diagnosed in 21 of the 44 patients during the 12-month period, and in 14 patients recurrence was suspected. Histological confirmation of recurrent Crohn's disease, however, was obtained unequivocally in only 11 patients, while in further 20 patients there was suspicion of recurrence. A large proportion of the recurrences was already confirmed endoscopically and histologically by the end of the third postoperative month. It is concluded that recurrences are frequent and early after a "curative" operation, raising the question of early prophylaxis with drugs.