A common classification framework for neuroendocrine neoplasms: an International Agency for Research on Cancer (IARC) and World Health Organization (WHO) expert consensus proposal.

The classification of neuroendocrine neoplasms (NENs) differs between organ systems and currently causes considerable confusion. A uniform classification framework for NENs at any anatomical location may reduce inconsistencies and contradictions among the various systems currently in use. The classification suggested here is intended to allow pathologists and clinicians to manage their patients with NENs consistently, while acknowledging organ-specific differences in classification criteria, tumor biology, and prognostic factors. The classification suggested is based on a consensus conference held at the International Agency for Research on Cancer (IARC) in November 2017 and subsequent discussion with additional experts. The key feature of the new classification is a distinction between differentiated neuroendocrine tumors (NETs), also designated carcinoid tumors in some systems, and poorly differentiated NECs, as they both share common expression of neuroendocrine markers. This dichotomous morphological subdivision into NETs and NECs is supported by genetic evidence at specific anatomic sites as well as clinical, epidemiologic, histologic, and prognostic differences. In many organ systems, NETs are graded as G1, G2, or G3 based on mitotic count and/or Ki-67 labeling index, and/or the presence of necrosis; NECs are considered high grade by definition. We believe this conceptual approach can form the basis for the next generation of NEN classifications and will allow more consistent taxonomy to understand how neoplasms from different organ systems inter-relate clinically and genetically

Animal models for COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the aetiological agent of coronavirus disease 2019 (COVID-19), an emerging respiratory infection caused by the introduction of a novel coronavirus into humans late in 2019 (first detected in Hubei province, China). As of 18 September 2020, SARS-CoV-2 has spread to 215 countries, has infected more than 30 million people and has caused more than 950,000 deaths. As humans do not have pre-existing immunity to SARS-CoV-2, there is an urgent need to develop therapeutic agents and vaccines to mitigate the current pandemic and to prevent the re-emergence of COVID-19. In February 2020, the World Health Organization (WHO) assembled an international panel to develop animal models for COVID-19 to accelerate the testing of vaccines and therapeutic agents. Here we summarize the findings to date and provides relevant information for preclinical testing of vaccine candidates and therapeutic agents for COVID-19

DNA extraction from paraff in-em bedded tissues using a salting-out procedure, a reliable method for PCR amplification of archiva1 material

Many techniques have been described for the extraction of DNA from paraffin-embedded tissues. Numerous efforts have been directed at simplification of these methods for rapid analysis using PCR. One disadvantage to some of the simpler procedures is inefficient PCR amplification, and for more involved ones using phenol/chloroform extraction, reduction in the yield of DNA. In the present study we report the use of a novel salting-out procedure that was utilized to extract DNA from 259 separate microdissection specimens of formalin-fixed, paraffin-embedded tissue sections. These sections were derived from 97 patients with tumors of the ampulla of Vater resected between 1965 and 1995 at our institution. The mean DNA yield was 22.75 pg (median 13.2130.25) and the mean 2601280 absorbance ratio was 1.68 (median 1.7020.25). Al1 specimens (2591259) were successfully used to amplify K-ras exon 1 by a nested PCR technique. These results indicate that this DNA extraction method produces good yields of quality DNA, even from specimens several decades old

Preferential Expression of MUC6 in Oncocytic and Pancreatobiliary Types of Intraductal Papillary Neoplasms Highlights a Pyloropancreatic Pathway, Distinct From the Intestinal Pathway, in Pancreatic Carcinogenesis

The expression of different MUC glycoproteins has helped define cellular lineage in variety of pancreatic neoplasms, and has helped identify distinct carcinogenic pathways such as the intestinal pathway characterized by diffuse/strong MUC2/CDX2 expression in intestinal-type intraductal papillary mucinous neoplasms (IPMNs) and their associated colloid carcinomas (CCs). In this study, the expression profile of MUC6, a pyloric-type mucin, was investigated in both preinvasive and invasive pancreatic neoplasia.Florid papillary ("in-situ") components of 9 intraductal oncocytic papillary neoplasms (IOPNs), 24 IPMNs, and 7 mucinous cystic neoplasms (MCNs), were analyzed immunohistochemically for MUC6 expression, as were 15 PanINs, 112 usual invasive ductal adenocarcinomas (DAs), and 14 CCs.In PanINs, MUC6 expression was limited to the very early areas of PanIN-1A that typically have pyloric features. Expression was lost in later stages. Similarly, in IOPNs or IPMNs or MCNs, MUC6 expression was detectable in the cystic or flat areas that have pyloric-like histology. However, in the more advanced (papillary) components of these neoplasms, MUC6 expression was mostly limited to the "cuboidal-cell" but was not seen in the "columnar-cell" phenotype: there was diffuse or strong expression in 8/9 IOPN and, relatively weaker but consistent expression in all 6/6 pancreatobiliary-type IPMNs; whereas virtually no expression in villous or intestinal-type IPMNs. The 7/8 gastric or foveolar-type IPMNs were also negative; in the single case with positivity, the labeling was limited to high-grade dysplastic areas. Interestingly, the papillae in MCNs were also mostly negative. Among invasive carcinomas, 39/112 DAs and only 1/14 CC expressed MUC6. In DA, the expression did not correlate with survival (P=0.94), or any of the markers of aggressiveness: more than 2-cm tumor size (P=0.76), positive surgical margins (P=0.27), lymph node metastasis (P =0.82), or high grade (P=0.08).In conclusion: (1) The expression of MUC6 in oncocytic and pancreatobiliary-type neoplasms but not in villous or intestinal-type neoplasms supports the presence of a pyloropancreatic pathway distinct from the MUC2/CDX2 expressing intestinal pathway in intraductal papillary neoplasia. (2) MUC6 expression is present in the earliest (nonpapillary) form of any type of preinvasive neoplasia regardless of whether it is PanIN or IOPN or IPMN or MCN suggesting that these entities may share some characteristics early on, but evolve along divergent pathways as they progress