[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.

[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.

[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.

[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.

[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.

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 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).

[Polyps of the colorectum: non-neoplastic and non-hamartomatous]. / Polypen im Kolorektum: Nichtneoplastisch und nichthamartomatös.

Non-neoplastic and non-hamartomatous colorectal polyps or tumor-like lesions comprise a very heterogeneous group of changes in the colorectal mucosa or the colon wall. Mucosal prolapse-associated lesions and inflammatory polyps, which are predominantly associated with chronic inflammatory bowel disease, are the most prominent examples for polypoid lesions difficult to distinguish from neoplastic lesions such as adenomas, hyperplastic/serrated polyps/adenomas and invasive carcinomas. The considerably less frequent tumor-like lesions like heterotopias, endometriosis, amyloid tumors and pseudolipomatous changes are histologically often well defined and should be considered in the differential diagnosis of colorectal lesions. The etiology, endoscopic and histological appearance of these entities and their most important differential diagnoses are discussed.

[Anal cancer: diagnostic and differential diagnostic issues]. / Das Analkanalkarzinom: Diagnostische und differenzialdiagnostische Aspekte.

Tumors of the anal canal are mostly epithelial in origin. The transition of gland-forming rectal mucosa via specialized urothelium-like cells at the dentate line to anal non-keratinized and finally perianal keratinized squamous epithelium implies a broad spectrum of tumor types, with most cancers exhibiting a mixture of different histological features. Moreover, secondary neoplasias extending into or metastasizing to the anal region need to be considered. Based on epithelial metaplasia at the transformation zone, poorly differentiated squamous anal carcinomas may show co-expression of both the squamous (CK5/6) and glandular type keratins (CK7). Since HPV infection of high-risk types (often 16 and 18) is etiologically associated with anal cancer, p16(INK4a) is highly sensitive and specific in the detection of high-grade anal squamous intraepithelial neoplasias (ASIN) and corresponding invasive squamous carcinomas. Diagnosis of secondary malignancies, including pagetoid extension into the anogenital region, requires the application of specific immunohistochemical marker panels.

Enhancement of experimental metastasis by tumor necrosis factor.

The influence of endogenous and exogenous tumor necrosis factor (TNF) on metastasis was investigated in an experimental fibrosarcoma metastasis model. A single intraperitoneal injection of recombinant human (rh) TNF or recombinant mouse (rm) TNF into mice 5 h before intravenous inoculation of methylcholanthrene-induced fibrosarcoma cells (CFS1) induced a significant enhancement of the number of metastases in the lung. Dose responses of rmTNF and rhTNF demonstrated a stronger metastasis-augmenting effect by rmTNF compared with rhTNF. This effect was time dependent, as administration of rmTNF 5 h before or 1 h but not 24 h after tumor cell inoculation caused an increase of tumor cell colony formation on the lung surface, suggesting an influence of TNF on the vascular adhesion and diapedesis of tumor cells. Since tumor-bearing mice showed an enhanced ability to produce TNF after endotoxin injection compared to control mice, tumor-bearing mice were treated with anti-mTNF antibodies. Neutralization of endogenous tumor-induced TNF led to a significant decrease of the number of pulmonary metastases. Histological analysis of micrometastases in the lung on day 5 by silver staining of proteins associated with nucleolar organizer regions revealed more metastatic foci and augmented proliferative activity of the tumor cells after rmTNF pretreatment of mice. However, no direct effect of rmTNF on the proliferation rate of tumor cells was seen in vitro. These findings suggest that low doses of endogenous TNF or administered TNF during cytokine therapy might enhance the metastatic potential of circulating tumor cells.

[Differential diagnostics of hereditary colorectal cancer syndromes. The role of pathology]. / Differenzialdiagnostik erblicher Dickdarmkarzinomsyndrome. Der Beitrag der Pathologie.

One third of colorectal carcinomas (CRC) show familial clustering of which about 5% have a monogenetic trait. Distinction between disease with and without polyposis, tumor histology and tumor spectrum in a given patient are all of diagnostic relevance. Familial adenomatous polyposis (FAP) underlies approximately 1% of CRC characterized by rapidly forming (>100) adenomas. In contrast to these about 2%-3% of CRC have a hereditary background without polyposis (HNPCC). This is the only hereditary tumour syndrome to date for which a tissue-based molecular screening test is available. Accordingly, expression analysis of mismatch repair genes (MSH2, MSH6 and MLH1, PMS2) is performed first. In the case of an equivocal result with no complete loss of expression testing of microsatellite instability (MSI) is added. In contrast to the other diseases MYH-associated polyposis (MAP) follows a recessive trait with polyp numbers usually between 15-30 adenomas and should be distinguished from attenuated forms of FAP with <100 polyps in the differential diagnosis. In the case of suspected familial cancer syndrome genetic counseling is warranted in order to decide ultimately whether there is an indication for genetic testing (evidence of a germ-line mutation).

[Her2 testing in gastric cancer. What is different in comparison to breast cancer?]. / Her2-Diagnostik beim Magenkarzinom. Was ist anders im Vergleich zum Mammakarzinom?

Based on data from a large multicenter phase III trial (ToGA study) trastuzumab has very recently been approved by the EMEA for metastatic gastric cancer and adenocarcinoma of the gastro-esophageal junction. Only patients with tumors which over express Her2 as defined by IHC2+ and a confirmatory FISH+ result, or IHC 3+, determined by an accurate and validated assay are eligible for trastuzumab therapy. However, testing of Her2 status by immunohistochemistry (IHC) differs from breast cancer in core aspects: 1. IHC2+/3+ is scored even though membranous staining is incomplete if membrane staining is clearly detectable even at low magnification (2.5x/5x, 3+) or medium magnification (10x/20x, 2+). 2. Additionally, membrane staining at the appropriate intensity found in at least 10% of tumor cells is restricted to resection specimens. Evaluation of Her2 in situ hybridization (ISH) is similar to breast cancer with ratio values of > or =2.0 indicating Her2 gene amplification. Taking these modifications into account and defining the HER2 positive subgroup as IHC 3+ and IHC2+/FISH+, approximately 16% of gastric cancers are considered Her2 positive, affecting mainly tumor regions with intestinal (gland forming) type carcinoma. In contrast to breast cancer, up to one-third of gastric cancers show a heterogeneous Her2 status both at IHC and ISH levels which favors bright field ISH over FISH.