The rapid development of molecular technologies and targeted therapies has fostered the implementation of specialized tumor conferences, known as molecular tumor boards (MTBs). MTBs become particularly important when tre...The rapid development of molecular technologies and targeted therapies has fostered the implementation of specialized tumor conferences, known as molecular tumor boards (MTBs). MTBs become particularly important when treatment recommendations are needed based on molecular alterations beyond the approved targeted therapies. While an MTB's goals are based on individualized diagnostics and therapies of tumor patients using innovative technologies and biomarkers, the procedures of MTBs are still quite heterogeneous. This applies to the primary inclusion criteria for tumor patients, the composition of MTBs, the applied diagnostic tests and their assessment and reporting, the evaluation of their clinical value and implementation in a therapeutic strategy, and the associated quality assurance measurements as well as knowledge-gaining, economical, legal, and ethical aspects.This article provides an overview of the spectrum of MTBs, their challenges, and the potential for individualized cancer medicine.
The enormous increase in sequencing capacity due to the development of next generation sequencing technologies opens up new opportunities in the fields of histopathology, research, and diagnostics, but also poses huge ch...The enormous increase in sequencing capacity due to the development of next generation sequencing technologies opens up new opportunities in the fields of histopathology, research, and diagnostics, but also poses huge challenges.The identification of genomic aberrations (point mutations, small insertions and deletions, fusion transcripts, and tumor mutation burden (TMB)) have already become a reliable part of routine molecular diagnostics. This will be supplemented by additional applications, namely gene amplifications, microsatellite instability, genomic signatures like homologous recombination deficiency (HRD), mRNA expression patterns, B‑ and T‑cell clonality, and DNA methylation. Challenges in preanalytics and the evaluation of assay sensitivity and specificity as well as proper curation of identified aberrations, which requires a new type of specialist, are presented and discussed.
Metastatic castration-resistant prostate cancer (mCRPC) is considered as the final stage of the disease with limited therapeutic options to date. In this article, we review recent histopathologic and molecular pathologic...Metastatic castration-resistant prostate cancer (mCRPC) is considered as the final stage of the disease with limited therapeutic options to date. In this article, we review recent histopathologic and molecular pathologic findings that may expand our understanding of the disease and may lay, or have already laid the groundwork for the development of novel and individualized therapies. These include the detection of pathogenic mutations in the DNA repair genes BRCA1/2, androgen receptor splice variant 7 (AR-V7), deletion of the tumor suppressor gene PTEN, and evidence of neuroendocrine prostate cancer (t-NEPC) arising under antiandrogenic therapy. The theoretical and diagnostic basis behind the increasing relevance of pathology for therapeutic guidance in this stage of disease are presented.
The role of pathologist Hans Klein during the National Socialist era and his career in post-war Germany have hardly received systematic attention. During World War II, Hans Klein worked in two medical institutions, where...The role of pathologist Hans Klein during the National Socialist era and his career in post-war Germany have hardly received systematic attention. During World War II, Hans Klein worked in two medical institutions, where he collaborated with individuals who were significantly involved in Nazi crimes. Klein's participation initially extended mainly to his work as an employed pathologist at the Rudolf Virchow Hospital in Berlin. There he was introduced to autopsy practices in the context of the children's euthanasia programme and autopsies of victims of medical experiments. Later, a shift in his activities is noticeable at the Hohenlychen Sanatorium. Klein's activities there increasingly involved independent research or voluntary collaboration in the projects of other scientists that were closely connected to the SS and experiments on human beings in concentration camps. He never had to face justice. His role was not further investigated by the Allies - probably due to his non-existent Nazi party and SS membership.
BACKGROUND: DNA double-strand breaks may evoke cell death or cancer. Cells have developed two fundamentally different mechanisms of DNA double-strand repair: the accurate mechanism of homologous recombination repair and...BACKGROUND: DNA double-strand breaks may evoke cell death or cancer. Cells have developed two fundamentally different mechanisms of DNA double-strand repair: the accurate mechanism of homologous recombination repair and the error-prone nonhomologous end joining. The deficiency of homologous recombination repair (HRD) is a frequent feature of several solid tumor entities and is associated with sensitivity to poly(ADP-ribose) polymerase (PARP) inhibitor therapy. OBJECTIVES: Among other biomarkers, HRD testing provides an opportunity to guide PARP inhibitor therapy in solid tumors, but the basic principles are complex and the use and benefits of the different methodologies remain controversial. Knowledge of the underlying mechanisms at the molecular level will advance our understanding and will pave the way to introduce the testing of new biomarkers. METHODS: An overview of the fundamental mechanisms of DNA repair is provided. Important terms like HRR, HRD, and BRCAness are defined, and analysis methods are described, especially with regard to their integration in molecular pathology routine diagnostics. RESULTS: Currently, at least testing of the BRCA mutation status and genomic instability using a composite HRD score should be implemented in laboratories to identify subgroups of patients who might benefit from PARP inhibitor therapies. A broad range of testing methods is available with pros and cons for introduction in the clinical setting. They have to be validated carefully to reliably inform treatment selection. CONCLUSIONS: Biomarkers to identify current homologous recombination deficiency status are needed to predict the benefit from PARP inhibitors and stratify their use in clinical management. Besides commercial assays, different tests might be used for the analysis of HRD. The application depends, among other things, on the local situation and has to be extensively validated.
From the very beginning, special attention regarding severe acute respiratory syndrome-coronavirus‑2 (SARS-CoV-2) and the resulting coronavirus disease-2019 (COVID-19) has been paid to pregnant women.In this review, afte...From the very beginning, special attention regarding severe acute respiratory syndrome-coronavirus‑2 (SARS-CoV-2) and the resulting coronavirus disease-2019 (COVID-19) has been paid to pregnant women.In this review, after a short introduction into the immunodefensive role of the placenta and viral infections in general, we describe the morphological changes of the placenta in SARS-CoV-2-infected pregnant women based on our own and other published studies, draw comparisons to the SARS epidemic, and discuss the question of vertical transmission of SARS-CoV‑2 from the mother to the neonate.The most common pathological findings of the placenta in SARS-CoV‑2 infection are signs of maternal and fetal malperfusion as well as potentially immunologically and/or thromboinflammation-mediated findings. These manifest as infarcts and decidual vasculopathy as well as thrombi in the fetal circulation and avascular villi. In some cases, there is also an inflammatory reaction with villitis, intervillositis, and fetal vasculitis. In addition, it has been shown that SARS-CoV‑2 can directly infect the placenta, so vertical transmission is possible.There is no COVID-19 specific pattern of placental alterations, although the detection of fetal thrombovasculitis, villitis, and intervillositis as well as fetal and maternal malperfusion could be best interpreted as the signature of SARS-CoV‑2 infection - considering the known pathophysiology of COVID-19 regarding other organs (inflammatory reaction and [micro]angiopathy). Detection of viral RNA in the fetal placental tissue and the umbilical cord indicates SARS-CoV‑2 vertical transmission.
Based on new trial data regarding immune checkpoint inhibitors (ICIs), the detection of high-grade microsatellite instability (MSI-H) or underlying deficient mismatch repair protein (dMMR) is now becoming increasingly im...Based on new trial data regarding immune checkpoint inhibitors (ICIs), the detection of high-grade microsatellite instability (MSI-H) or underlying deficient mismatch repair protein (dMMR) is now becoming increasingly important for predicting treatment response. For the first time, a PD‑1 ICI (pembrolizumab) has been approved by the European Medicines Agency (EMA) for first-line treatment of advanced (stage IV) dMMR/MSI‑H colorectal cancer (CRC). Further indications, such as dMMR/MSI‑H endometrial carcinoma (EC), have already succeeded (Dostarlimab, 2nd line treatment) and others are expected to follow before the end of 2021. The question of optimal testing in routine diagnostics should therefore be re-evaluated. Based on a consideration of the strengths and weaknesses of the widely available methods (immunohistochemistry and PCR), a test algorithm is proposed that allows quality assured, reliable, and cost-effective dMMR/MSI‑H testing. For CRC and EC, testing is therefore already possible at the primary diagnosis stage, in line with international recommendations (NICE, NCCN). The clinician is therefore enabled from the outset to consider not only the predictive but also the prognostic and predispositional implications of such a test when counseling patients and formulating treatment recommendations. As a basis for quality assurance, participation in interlaboratory comparisons and continuous documentation of results (e.g., QuIP Monitor) are strongly recommended.
Paraffin histology is one of the most important and commonly used laboratory techniques in diagnostic histopathology. The discovery of paraffin embedding is often attributed to the pathologist Edwin Klebs. Klebs was foll...Paraffin histology is one of the most important and commonly used laboratory techniques in diagnostic histopathology. The discovery of paraffin embedding is often attributed to the pathologist Edwin Klebs. Klebs was following the lead of Stricker, who embedded embryos in a mixture of hot stearin and white beeswax. We show that Klebs experimented with paraffin wax for embedding tumour tissue. But he quickly rejected it as unsuitable because paraffin wax did not infiltrate the tissue. One of Klebs' correspondents, embryologist Wilhelm His, Sr., learned of Klebs' experiments and decided to try paraffin embedding. His dehydrated chicken embryos in alcohol, cleared them in lavender oil, and dripped hot paraffin wax onto them. This process allowed His to cut good sections. Here, we have replicated His's paraffin embedding protocol in order to determine whether His had indeed made the landmark discovery of infiltration embedding with paraffin wax. We followed the protocol that he gives in his 1868 monograph on the early development of the chicken. The protocol described by His failed, in our hands, to yield sections of the quality that he illustrates in his monograph. Typically, the tissue disintegrated when sectioned due to poor infiltration of the wax. Usable sections could only be obtained if His's protocol was modified by melting the embedded embryos in fresh paraffin wax. One explanation for our findings is that we failed to faithfully replicate His's protocol. Another is that his protocol was incomplete. We suggest that His is likely to have discovered and perfected infiltration embedding with paraffin wax but did not publish a complete protocol.
In the past 25 years, treatment of metastatic colorectal cancer (mCRC) has undergone profound changes. The approval of newer chemotherapeutics such as irinotecan and oxaliplatin was followed in 2005 by the first targeted...In the past 25 years, treatment of metastatic colorectal cancer (mCRC) has undergone profound changes. The approval of newer chemotherapeutics such as irinotecan and oxaliplatin was followed in 2005 by the first targeted therapies, for example, monoclonal antibodies directed against the epidermal growth factor receptor (EGFR), as cetuximab and panitumumab, or the angiogenesis inhibitors bevacizumab, ramucirumab, and aflibercept. With the rapidly progressing molecular characterization of mCRC in the last 10 years and the classification of the disease in four consensus subtypes, further changes are emerging, which will promote, among other things, the introduction of protein-kinase inhibitors developed for specific molecular aberrations as well as immune checkpoint inhibitors into the treatment algorithm.Thorough molecular pathologic testing is indispensable today for guideline-compliant treatment of mCRC patients. In addition to RAS testing as a precondition for the therapy decision with regard to cetuximab and panitumumab, BRAF testing is of considerable relevance to allow decision making with regard to the newly approved chemotherapy-free combination of the BRAF inhibitor encorafenib and cetuximab in cases where a BRAF-V600E mutation is detected. Additional diagnostic tests should also include genome instability (microsatellite instability). Overall, more and more molecular alterations need to be investigated simultaneously, so that the use of focused next-generation sequencing is increasingly recommended.This overview describes the prognostic relevance of BRAF testing in the context of molecular pathologic diagnostics of mCRC, presents new treatment options for BRAF-mutated mCRC patients, and explains which modern DNA analytical and immunohistochemical methods are available to detect BRAF mutations in mCRC patients.
Diagnostic radiology and diagnostic pathology are medical disciplines that use a variety of morphological analyses with different macroscopic and microscopic resolutions for diagnosis and staging of cancers. In the clini...Diagnostic radiology and diagnostic pathology are medical disciplines that use a variety of morphological analyses with different macroscopic and microscopic resolutions for diagnosis and staging of cancers. In the clinical setting, radiology and pathology departments are often spatially separated. However, there are examples of increasingly tight cooperation and convergence, for example in the setting of multidisciplinary tumor boards. This article focuses exemplarily on the correlations of radiological and histopathological diagnostics in pancreatic cancer.
Checkpoint inhibitors have revolutionized oncological treatment in many cancers and added a new immuno-oncological treatment pillar to the medicinal arsenal of conventional and molecularly targeted therapies. In monother...Checkpoint inhibitors have revolutionized oncological treatment in many cancers and added a new immuno-oncological treatment pillar to the medicinal arsenal of conventional and molecularly targeted therapies. In monotherapy and in combination therapies, however, not all patients respond equally well, even in generally responsive tumor entities. Therefore, since the introduction of these therapies, a major focus has been the research on and implementation of predictive markers for patient selection. The first established biomarker, the expression of the target molecule PD-L1, has found its way into routine diagnostics in a large number of unfortunately very divergent diagnostic constellations in multiple entities. In addition, some molecular predictors, including the measurement of microsatellite instability and tumor mutational burden, have also been suggested and in some cases are already implemented into routine diagnostics. Additional molecular parameters have been proposed but most of them have not yet found their way into routine patient care. This review article discusses the current status and recent developments in the field of diagnostic response predictors in the context of an immune checkpoint blockade.
BACKGROUND: A dysregulated immune response is considered one of the major factors leading to severe COVID-19. Previously described mechanisms include the development of a cytokine storm, missing immunoglobulin class swit...BACKGROUND: A dysregulated immune response is considered one of the major factors leading to severe COVID-19. Previously described mechanisms include the development of a cytokine storm, missing immunoglobulin class switch, antibody-mediated enhancement, and aberrant antigen presentation. OBJECTIVES: To understand the heterogeneity of immune response in COVID-19, a thorough investigation of histomorphological patterns in regional lymph nodes was performed. MATERIALS AND METHODS: Lymph nodes from the cervical, mediastinal, and hilar regions were extracted from autopsies of patients with lethal COVID-19 (n = 20). Histomorphological characteristics, SARS-CoV‑2 qRT-PCR, and gene expression profiling on common genes involved in immunologic response were analyzed. RESULTS: Lymph nodes displayed moderate to severe capillary stasis and edema, an increased presence of extrafollicular plasmablasts, mild to moderate plasmacytosis, a dominant population of CD8 T‑cells, and CD11c/CD68 histiocytosis with hemophagocytic activity. Out of 20 cases, 18 presented with hypoplastic or missing germinal centers with a decrease of follicular dendritic cells and follicular T‑helper cells. A positive viral load was detected by qRT-PCR in 14 of 20 cases, yet immunohistochemistry for SARS-CoV-2 N-antigen revealed positivity in sinus histiocytes of only one case. Gene expression analysis revealed an increased expression of STAT1, CD163, granzyme B, CD8A, MZB1, and PAK1, as well as CXCL9. CONCLUSIONS: Taken together, our findings imply a dysregulated immune response in lethal COVID-19. The absence/hypoplasia of germinal centers and increased presence of plasmablasts implies a transient B‑cell response, implying an impaired development of long-term immunity against SARS-CoV‑2 in such occasions.
Increasingly extensive genomic diagnostics in cancer precision medicine require uniform evaluation criteria for the classification of variants with regard to their functional and therapeutic implications. In this review...Increasingly extensive genomic diagnostics in cancer precision medicine require uniform evaluation criteria for the classification of variants with regard to their functional and therapeutic implications. In this review we present the most important guidelines and classification systems currently used in daily clinical practice, explain their advantages and disadvantages as well as differences and similarities, and present the step-by-step, systematic process that enables successful variant interpretation.
The 2017 WHO classification of pituitary tumors is still based on structural analyses and expression of various pituitary hormones. Three innovations have to be considered: (1) The expression of pituitary transcription f...The 2017 WHO classification of pituitary tumors is still based on structural analyses and expression of various pituitary hormones. Three innovations have to be considered: (1) The expression of pituitary transcription factors Pit‑1, T‑Pit and SF‑1. (2) The term "atypical adenoma" was replaced by "aggressive adenoma". (3) The three tumor types of the neurohypophysis (pituicytoma, spindle cell oncocytoma, granular cell tumor) are defined by their common expression of TTF‑1. Craniophyryngiomas are identified as adamantinomatous type by focal nuclear expression of β‑catenin or as papillary type by demonstration of BRAF V600E mutation. Further primary tumors of the pituitary are extremely rare. These and also the other tumors of the sellar region can be structurally very similar to pituitary adenomas but can be-nearly without exception-differentiated by immunocytochemistry.
Digital formats have become an indispensable part of academic teaching, including education and training in pathology. Their use offers the perspective of rendering conventional teaching formats more diversified and more...Digital formats have become an indispensable part of academic teaching, including education and training in pathology. Their use offers the perspective of rendering conventional teaching formats more diversified and more flexible since students can adopt the timing and learning speed to their individual needs. However, digital formats should be designed to fulfill the intended didactic purpose within a teaching concept that addresses competences and specific aims. The current view is that E‑learning neither will nor should replace face-to-face teaching, but that both can fuse into blended-learning formats using the best of both worlds. It is important to view the implementation of E‑learning as a dynamic process that should be underpinned by didactic research and be constantly developed further through evaluation and feedback from both teachers and students.
Deficient mismatch repair (dMMR) and microsatellite instability (MSI) have therapeutic relevance not only for colorectal carcinomas but also for carcinomas of other entities (endometrium, biliary tract, pancreas). In ord...Deficient mismatch repair (dMMR) and microsatellite instability (MSI) have therapeutic relevance not only for colorectal carcinomas but also for carcinomas of other entities (endometrium, biliary tract, pancreas). In order to guarantee the knowledge and good technical quality necessary for adequate implementation of the corresponding analyses in pathology institutes, the Pathology Quality Assurance Initiative ("Die Qualitätssicherung-Initiative Pathologie") has been offering proficiency tests (PT) for years. It has been shown for the dMMR PT that various antibody clones from different manufacturers provide comparable results in immunohistological examinations, except for slight variations. The difficulty lies in the staining protocol (intensity of staining) and the interpretation of the staining results. The molecular pathological MSI PT has shown a positive trend at a high-quality level over the last three years. Success rates increased from 89 (2018) to 97% (2019/2020). The choice of assay, whether commercial or in-house tests with the designated cutoffs for this purpose, has not been shown to have a significant impact on the PTs in the selected EQA samples.
BACKGROUND: The classification of renal cell carcinoma (RCC) has changed remarkably in recent years. OBJECTIVES: This is a short overview of the classification of RCC, focusing on new developments. MATERIALS AND METHODS:...BACKGROUND: The classification of renal cell carcinoma (RCC) has changed remarkably in recent years. OBJECTIVES: This is a short overview of the classification of RCC, focusing on new developments. MATERIALS AND METHODS: A literature search was performed resulting in an overview of the classification of RCC. Emerging entities were discussed in detail. RESULTS: Apart from the RCC subtypes in the WHO classification of 2016, several emerging entities came up over the last few years that are characterized by typical morphology, immunophenotype, and especially specific genetic alterations. CONCLUSION: Precise classification of RCC is the key to better prognostic assessment with potential tumor-specific therapy and plays an important role in the recognition of possible association with hereditary tumor syndromes.
Whereas predictive immunohistochemistry has represented a core element of breast cancer classification for decades, predictive molecular pathology, with the exception of in situ hybridization for assessment of HER2 ampli...Whereas predictive immunohistochemistry has represented a core element of breast cancer classification for decades, predictive molecular pathology, with the exception of in situ hybridization for assessment of HER2 amplification, has only recently gained importance because novel drugs have been approved for treatment of metastatic disease. For the use of PARP inhibitors, proof of BRCA1 or BRCA2 mutation is mandatory. When mutation of the catalytic subunit α of the phosphatidylinositol‑4.5‑bisphosphate 3‑kinase gene (PIK3CA) is present, which can be encountered in up to 40% of luminal breast cancers, the option for treatment with the specific inhibitor alpelisib arises. The HER2 -encoded growth factor receptor contributes to neoplastic transformation not only by amplification and overexpression but also by activating the mutation of the kinase domain, which is responsive to tyrosine kinase inhibitors of the tucatinib/neratinib type. Up to 30% of metastatic and endocrine treated luminal breast cancers acquire an activating mutation of the estrogen receptor gene ESR1, resulting in an autocrine and ligand-independent growth stimulation resistant to aromatase inhibitors. Larotrectinib-sensitive mutation of tropomyosinreceptor kinase is present in up to 50% of secretory breast cancers, whereas the other histologic subtypes display an incidence of below 1%. In conclusion, predictive molecular pathology has gained importance in metastatic breast cancer.