[Microsatellite instability : Review of methods and applications]. / Mikrosatelliteninstabilität : Aktueller Überblick über Methoden und Anwendungen.

After introduction of the Bethesda microsatellite test panel demonstration of microsatellite instability (MSI) and/or loss of mismatch repair proteins (MMRD) was primarily used as a marker for cancer predisposition of Lynch syndrome (LS, previous: HNPCC). Nowadays MSI/MMRD has become an important biomarker to predict therapy response to checkpoint immunotherapies. MSI can be determined either by polymerase chain reaction (PCR)-based technologies with or without specification of fragment sizes or next generation sequencing (NGS) methods. Depending on the individual tumor entities, these test methods are used differently. Currently, MSI/MMRD is a tumor biomarker which covers a broad spectrum of indications in tumor pathology, especially in colorectal, endometrial and gastric cancer. In advanced carcinomas, MSI is an established predictor of therapy response to checkpoint-directed immunotherapies.

[Hereditary colorectal cancer : An update on genetics and entities in terms of differential diagnosis]. / Hereditäres Dickdarmkarzinom : Ein Update zu Genetik und Entitäten aus differenzialdiagnostischer Sicht.

The pathologist can contribute to recognizing hereditary causes of colorectal cancer via morphology. By identifying so-called index patients, it is possible to take preventive measures in affected families. The precise definition of the clinical presentation and the histopathological phenotype help to narrow the spectrum of expected genetic alterations. Novelties within Lynch syndrome include the recognition of EPCAM as a fifth gene locus, as well as the newly defined Lynch-like syndrome with evidence of somatic mismatch repair (MMR) mutations. With regard to polyposis-associated syndromes, the spectrum of polyps, whether serrated, hamartomatous or classic adenoma, is of crucial importance. The resulting differential diagnosis includes (attenuated) familial adenomatous polyposis ([a]FAP), MUTYH-associated polyposis (MAP), polymerase proofreading-associated polyposis (PPAP), phosphatase and tensin homolog (PTEN) hamartoma tumor syndrome (PHTS), Peutz-Jeghers syndrome and juvenile polyposis, each with a specific genetic background.

Quality assurance trials for Ki67 assessment in pathology.

Ki67 is a broadly used proliferation marker in surgical pathology with an obvious need for standardization to improve reproducibility of assessment. Here, we present results of the so far only existing round robin tests on Ki67, organized annually in Germany, Austria, and Switzerland from 2010 to 2015 with up to 160 participating laboratories (QuIP). In each quality assessment trial, eight probes from each breast cancer, neuroendocrine tumor, and malignant lymphoma were compiled on a tissue microarray (TMA). TMAs were stained in the participants' laboratories with antibodies and procedures also applied in their daily routine. Participating pathologists were expected to assign Ki67 values to one of four different categories for each tumor type. All local stainings and evaluations were reassessed by the organizing panel and compared to a preset standard. On average, 95% of participants reached the benchmark of over 80% concordance rates with the Ki67 category pre-established by the panel. Automatization and type of antibody did not affect the success rate. Concordance rates differed between tumor entities being highest in each tumor type with either very high or very low labeling indices. Lower rates were seen for intermediate Ki67 levels. Staining quality improved during the observation period as did inter-observer concordance with 85% of participants achieving excellent agreement (kappa > 0.8) in the first year and over 95% in 2015. In conclusion, regular external quality assurance trials have been established as a tool to improve the reproducibility and reliability of the prognostic and predictive proliferation marker Ki67.

[HER2 testing in gastric cancer - results of a German expert meeting]. / HER2-Testung beim Magenkarzinom - Ergebnisse eines deutschen Expertentreffens.

Valid HER2 testing is essential for optimal therapy of patients with HER2 positive gastric cancer and the correct use of first-line treatment. While each breast cancer is routinely being tested for the HER2 status, HER2 testing in gastric cancer has still not become part of the routine and is often only done upon request by the therapist. An interdisciplinary German expert group took the challenges of HER2 testing in gastric cancer as an opportunity to address essential aspects and questions for the practical use of HER2 testing in this indication from the perspective of pathologists and therapists. The recommendations made in this manuscript reflect the consensus of all participants and correspond to their opinions and long-term experience.

[Predictive PD-L1 immunohistochemistry for non-small cell lung cancer : Current state of the art and experiences of the first German harmonization study]. / Prädiktive PD-L1-Immunhistochemie beim nichtkleinzelligen Bronchialkarzinom : Aktueller Stand und Erfahrungen der ersten deutschen Harmonisierungsstudie.

BACKGROUND: Antibodies against PD-1 and PD-L1 can cause strong and durable anti-tumor immune responses in non-small cell lung cancer (NSCLC). Immunohistochemistry for PD-L1 (PD-L1 IHC) was tested as a predictive biomarker. Several IHC assays and interpretation criteria were developed in parallel. AIM: The clinical significance of PD-L1 IHC in NSCLC and the optimum method for staining and interpretation of the results are the subject of ongoing studies. The diagnostic application of immunotherapy in NSCLC necessitates harmonization of PD-L1 IHC to obtain evidence for guidelines; therefore, a consensus opinion on a well-founded diagnostic mode of testing should be defined based on published studies and the results of the first German PD-L1 IHC harmonization study. METHODS: 1. Summary of the current data situation. 2. Evaluation of the first German PD-L1 IHC harmonization study (centralized, staining with PD-L1 IHC analogous to studies, 15 cases of NSCLC, 4 IHC study assays [28­8, 22C3, SP142 and SP263] and scoring by 9 pathologists). RESULTS: The use of PD-L1 IHC in NSCLC is suitable for identification of patients with an increased probability of a clinical benefit from immunotherapy. The various proportional cut-offs used to interpret the staining results can be summarized in a total score, which can be reproducibly assessed. The staining patterns of the four assays investigated were, however, not congruent in all situations. DISCUSSION: In principle, the use of PD-L1 IHC for assessment of the expression in tumor cells is a reliably determinable biomarker. Evaluation algorithms should be based on published clinical trials. For NSCLC approvals with obligatory PD-L1 IHC are to be expected but it remains to be seen to what extent PD-L1 IHC will be implemented in the clinical routine.

[HER2 testing in gastric cancer : Results of a meeting of German experts]. / HER2-Testung beim Magenkarzinom : Ergebnisse eines deutschen Expertentreffens.

Valid HER2 testing is essential for the optimal care of patients with HER2-positive gastric cancer and the correct use of first-line treatment. Although all cases of breast cancer are routinely tested for the HER2 status, HER2 testing in gastric cancer has still not become part of the routine and is usually only done upon request by the therapist. An interdisciplinary group of German experts has taken on the challenges of HER2 testing in gastric cancer as an opportunity to address essential aspects and questions on the practical use of HER2 testing in this indication from the perspective of pathologists and therapists. The recommendations made in this article reflect the consensus of all participants and correspond to their opinions and long-term experience.

[Colorectal Carcinoma with Suspected Lynch Syndrome: A Multidisciplinary Algorithm]. / Kolorektales Karzinom bei V. a. Lynch-Syndrom: ein interdisziplinärer Algorithmus.

Lynch syndrome is the most frequent hereditary cancer syndrome, accounting for approximately 3-5 % of all colorectal cancers. In addition, it is the most frequent predisposing hereditary cause of endometrial cancer and is also associated with gastric cancer, ovarian cancer, cancer of the urinary tract as well as several other cancers. In clinical practise Lynch syndrome is frequently not detected and many clinicians admit uncertainties regarding diagnostic procedures. Also, counselling of patients is considered difficult regarding therapeutic - especially prophylactic surgical and chemopreventive options and recommendations. Based on a review of available literature we discuss optimized strategies for improved detection of suspected Lynch syndrome patients. The aim of this review is to establish a clinical algorithm of how to proceed on a diagnostic level and to discuss surgical options at the time of a colorectal cancer. In order to identify patients with Lynch syndrome, family history should be ascertained and evaluated in regards to fulfilment of the Amsterdam-II- and/or the revised Bethesda criteria. Subsequently immunohistochemical staining for the mismatch-repair-genes, BRAF testing for MLH1 loss of expression, as well as testing for microsatellite instability in some, followed by genetic counselling and mutation analysis when indicated, is recommended. Pathological identification of suspected Lynch syndrome is readily feasible and straightforward. However, the need of performing these analyses in the tumor biopsy at the time of (gastroenterological) diagnosis of CRC neoplasia is essential, in order to offer patients the option of a prophylactically extended surgery and - as recommended in the German S3 guidelines - to discuss the option of a merely prophylactical hysterectomy and oophorectomy (if postmenopausal) in women. Close cooperation between gastroenterologists, pathologists and surgeons is warranted, so that patients may benefit from options of extended or prophylactically extended surgery at the time of diagnosis of a colorectal primary. Patients nowadays must be involved in informed decision-making regarding prophylactic or extended prophylactic surgery at the time of a colorectal primary. To date, however, limitations in daily clinical practise, the failure to assess family history and the lack of awareness of this important hereditary syndrome is the major asset leading to severe underdiagnosis and putting to risk the indexpatients themselves and their families to (metachronous) CRC and the associated extracolonic cancers. If at all tumors of patients fulfilling Bethesda criteria will be analysed for MSI in the surgical specimen and therefore Lynch syndrome patients are not given the opportunity to opt for extended surgery. In clinical experience the postoperative MSI-analysis is inconsistently performed - even if the Bethesda criteria are fulfilled - and in case of suspected Lynch syndrome genetically counselling is not consistently recommended. Therefore affected cancer patients are left unaware of their increased genetic risk and in average 3 high-risk gene carriers per family miss the opportunity to actively engage in the recommended screening program.

SUPT6H controls estrogen receptor activity and cellular differentiation by multiple epigenomic mechanisms.

The estrogen receptor alpha (ERα) is the central transcriptional regulator of ductal mammary epithelial lineage specification and is an important prognostic marker in human breast cancer. Although antiestrogen therapies are initially highly effective at treating ERα-positive tumors, a large number of tumors progress to a refractory, more poorly differentiated phenotype accompanied by reduced survival. A better understanding of the molecular mechanisms involved in the progression from estrogen-dependent to hormone-resistant breast cancer may uncover new targets for treatment and the discovery of new predictive markers. Recent studies have uncovered an important role for transcriptional elongation and chromatin modifications in controlling ERα activity and estrogen responsiveness. The human Suppressor of Ty Homologue-6 (SUPT6H) is a histone chaperone that links transcriptional elongation to changes in chromatin structure. We show that SUPT6H is required for estrogen-regulated transcription and the maintenance of chromatin structure in breast cancer cells, possibly in part through interaction with RNF40 and regulation of histone H2B monoubiquitination (H2Bub1). Moreover, we demonstrate that SUPT6H protein levels decrease with malignancy in breast cancer. Consistently, SUPT6H, similar to H2Bub1, is required for cellular differentiation and suppression of the repressive histone mark H3K27me3 on lineage-specific genes. Together, these data identify SUPT6H as a new epigenetic regulator of ERα activity and cellular differentiation.

Discrepancies between medical oncologists and surgeons in assessment of resectability and indication for chemotherapy in patients with colorectal liver metastases.

BACKGROUND: Multidisciplinary discussion of the treatment of patients with colorectal liver metastases (CRLM) is advocated currently. The aim of this study was to investigate medical oncologists' and surgeons' assessment of resectability and indication for chemotherapy, and the effect of an educational intervention on such assessment. METHODS: Medical histories of 30 patients with CRLM were presented to ten experienced medical oncologists and 11 surgeons at an initial virtual tumour board meeting (TB1). Treatment recommendations were obtained from each participant by voting for standardized answers. Following lectures on the potential of chemotherapy and surgery, assessment was repeated at a second virtual tumour board meeting (TB2), using the same patients and participants. RESULTS: Overall, 630 answers (21 × 30) were obtained per tumour board meeting. At TB1, resectability was expected more frequently by surgeons. Participants changed 56·8 per cent of their individual answers at TB2. Assessment shifted from potentially resectable to resectable CRLM in 81 of 161 and from unresectable to (potentially) resectable CRLM in 29 of 36 answers. Preoperative chemotherapy was indicated more often by medical oncologists, and overall was included in 260 answers (41·3 per cent) at TB1, compared with only 171 answers (27·1 per cent) at TB2. Medical oncologists more often changed their decision to primary resection in resectable patients (P = 0·006). Postoperative chemotherapy was included in 51·9 and 52·4 per cent of all answers at TB1 and TB2 respectively, with no difference in changes between medical oncologists and surgeons (P = 0·980). CONCLUSION: Resectability and indication for preoperative chemotherapy were assessed differently by medical oncologists and surgeons. The educational intervention resulted in more patients deemed resectable by both oncologists and surgeons, and less frequent indication for chemotherapy.

[Determination of tumor biological parameters in breast cancer: round robin testing for quality assurance]. / Bestimmung tumorbiologischer Parameter beim Mammakarzinom: Ringversuche zur Qualitätssicherung.

Round robin testing for quality assurance in the determination of the breast cancer biomarkers estrogen receptor (ER), progesterone receptor (PR) and epithelial growth factor receptor 2 (HER2) have been carried out in Germany for 13 years. As the first quality assurance trial worldwide tissue microarrays with 20 different breast cancer specimens were used. As a further innovation the challenges were split into a test part representing routine cases and a training part enriched with difficult borderline cases in order to uncover latent weaknesses in the participating laboratories. Certificates are issued based exclusively on the test part. Similar to NordiQC and UKNequas stained slides are assessed externally and the quality of staining and evaluation are considered separately. Since 2010 an additional internet-based trial without assessment of the staining quality is offered for ER and PR. Since the introduction of the round robin trials the numbers of participants (n = 200-250) and the success rates have steadily increased. The breast cancer quality assurance trial ranks first with regard to the number of participants in Germany. It could be demonstrated that regular participation in the round robin test leads to an improvement of staining results of ER, PR and HER2 and hence appears to be mandatory for maintaining quality standards. The use of fully automated immunohistochemical staining procedures has steadily increased and these are now used by approximately 50 % of participants.

HER2/ErbB2 activates HSF1 and thereby controls HSP90 clients including MIF in HER2-overexpressing breast cancer.

Overexpression of the human epidermal growth factor receptor-2 (HER2) in breast cancer strongly correlates with aggressive tumors and poor prognosis. Recently, a positive correlation between HER2 and MIF (macrophage migration inhibitory factor, a tumor-promoting protein and heat-shock protein 90 (HSP90) client) protein levels was shown in cancer cells. However, the underlying mechanistic link remained unknown. Here we show that overexpressed HER2 constitutively activates heat-shock factor 1 (HSF1), the master transcriptional regulator of the inducible proteotoxic stress response of heat-shock chaperones, including HSP90, and a crucial factor in initiation and maintenance of the malignant state. Inhibiting HER2 pharmacologically by Lapatinib (a dual HER2/epidermal growth factor receptor inhibitor) or CP724.714 (a specific HER2 inhibitor), or by knockdown via siRNA leads to inhibition of phosphoactivated Ser326 HSF1, and subsequently blocks the activity of the HSP90 chaperone machinery in HER2-overexpressing breast cancer lines. Consequently, HSP90 clients, including MIF, AKT, mutant p53 and HSF1 itself, become destabilized, which in turn inhibits tumor proliferation. Mechanistically, HER2 signals via the phosphoinositide-3-kinase (PI3K)-AKT- mammalian target of rapamycin (mTOR) axis to induce activated pSer326 HSF1. Heat-shock stress experiments confirm this functional link between HER2 and HSF1, as HER2 (and PI3K) inhibition attenuate the HSF1-mediated heat-shock response. Importantly, we confirmed this axis in vivo. In the mouse model of HER2-driven breast cancer, ErbB2 inhibition by Lapatinib strongly suppresses tumor progression, and this is associated with inactivation of the HSF1 pathway. Moreover, ErbB2-overexpressing cancer cells derived from a primary mouse ErbB2 tumor also show HSF1 inactivation and HSP90 client destabilization in response to ErbB2 inhibition. Furthermore, in HER2-positive human breast cancers HER2 levels strongly correlate with pSer326 HSF1 activity. Our results show for the first time that HER2/ErbB2 overexpression controls HSF1 activity, with subsequent stabilization of numerous tumor-promoting HSP90 clients such as MIF, AKT and HSF1 itself, thereby causing a robust promotion in tumor growth in HER2-positive breast cancer.

HER2 staining intensity in HER2-positive disease: relationship with FISH amplification and clinical outcome in the HERA trial of adjuvant trastuzumab.

BACKGROUND: Trastuzumab treatment improves survival of HER2-positive primary breast cancer. HER2 staining intensity varies widely in HER2-positive tumours. PATIENTS AND METHODS: We investigated whether differences in immunohistochemical (IHC) staining intensity for HER2 in HER2-positive tumors (IHC 3+ or FISH ratio ≥2.0) was associated with prognosis or benefit from trastuzumab treatment in patients randomized to 1 year or no trastuzumab in the HERceptin Adjuvant (HERA) trial. Median follow-up was 2 years. The nested case-control analysis, included 425 patients (cases) with a disease-free survival (DFS) event and two matched controls (no DFS event) per case. Tissue sections stained for HER2 were assessed for HER2 staining intensity by image analysis. RESULTS: HER2 staining intensity varied widely and correlated with HER2 gene copy number (Spearman, r = 0.498, P < 0.001) or less closely with HER2/CEP17 FISH ratio (r = 0.396, P < 0.001). We found no significant difference in DFS in the observation arm according to staining intensity (odds ratio [OR] change per 10 unit change in intensity: 1.015, 95% confidence interval [CI] 0.930-1.108) and no impact of staining intensity on benefit derived from 1-year trastuzumab (OR: 1.017, 95% CI 0.925-1.120). CONCLUSIONS: Variability in HER2 staining in HER2-positive tumours has no role in clinical management with adjuvant trastuzumab. HERA TRIAL NO: NCT00045032.

[Angioinvasion by neuroendocrine jejunal tumor. Demonstration of a malignancy sign by acetone compression]. / Angioinvasion durch neuroendokrinen Jejunumtumor. Darstellung eines Malignitätszeichens durch Acetonkompression.

Neuroendocrine neoplasms of the digestive system are classified by current World Health Organization (WHO) guidelines as G1 and G2 neuroendocrine tumors (NET) as well as neuroendocrine carcinoma (NEC) based on proliferation and differentiation. The G1 NET tumors are highly differentiated, low proliferating and usually exhibit a favorable course of the disease without the development of metastases. In the case presented here, angioinvasion by a pT3 NET G1 was demonstrated after complete work-up of the mesenterial fat by acetone compression. The findings indicate an unfavorable course of disease requiring intensive surveillance.

Adenocarcinoma of the GEJ: gastric or oesophageal cancer?

According to WHO (2010) adenocarcinomas of the esophagogastric junction (GEJ) are defined as tumors that cross the most proximal extent of the gastric folds regardless of where the bulk of the tumor lies. In addition, these neoplasms are now classified as esophageal cancers by UICC (2010). Recent studies, however, revealed two types of carcinogenesis in the distal oesophagus and at the GEJ, one of intestinal type (about 80 %) and the other of gastric type (about 20 %). These are characterized by marked differences in morphology, tumor stage at diagnosis, and prognosis. Furthermore, both cancer types show different targetable biomarker expression profiles such as Her2 in the intestinal and EGFR in the non-intestinal pathway indicating new therapy options. Due to the fact that carcinomas of the intestinal pathway were typically associated with Barrett's mucosa which was not the case in the non-intestinal-type tumors, this challenges the paradigm "no goblets no Barrett's". Moreover, even the cancer risk of intestinal-type metaplasia has seriously been questioned by a Danish population-based study where Barrett's mucosa turned out to be only a weak indicator of esophageal and GEJ cancer (1 case in 860 patients years). Thus, two biologically different types of cancer arise at the GEJ-esophageal and gastric type that open distinctive targeted treatment options and also question our current concept about the diagnostics of potential precursor lesions as well as the associated screening and surveillance strategy.

[In situ hybridization in clinical pathology. Significance of polysomy 17 for HER2 determination and genetic tumor heterogeneity in breast cancer]. / In-situ-Hybridisierung in der klinischen Pathologie. Bedeutung der Polysomie 17 für die HER2-Bestimmung und genetische Tumorheterogenität im Mammakarzinom.

The introduction of total genome sequencing led to the confirmation that tumors show substantial genetic heterogeneity. This phenomenon, which describes the presence of different genetic cell clones within a tumor also complicates the diagnostics of HER2. This article gives a review of new knowledge on polysomy 17 and genetic tumor heterogeneity in connection with HER2 determination of breast cancer.

[Translational research and diagnostics of melanoma]. / Translationale Forschung und Diagnostik beim Melanom.

Although early stage malignant melanoma (MM) has a favorable prognosis five year survival rate is poor (<10%) in patients suffering from distant metastases. Due to molecular typing of MM recently high response rates were achieved in metastatic MM by using specific inhibitors directed against the mutated form of BRAF kinase, e.g. Vemurafinib and Dabrafinib. Therefore BRAF mutation analysis has become standard of care in advanced MM and pathologists are urged to provide a quality guaranteed molecular diagnostics. However, squamous neoplasias (e. g., keratoacanthomas) and recurrences of MM mostly within 6 months during targeted therapy point to the need of further translational research. Thus new drugs, such as MEK inhibitors, based on the MAP-kinase pathway downstream of BRAF have already effectively been used. Finally, the impact of molecular characteristics in different subtypes of MM (acral, mucosal, uveal) will be discussed with respect to their specific mutational spectrum (e.g. cKIT , NRAS , GNAQ).