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Given advances in diagnostic imaging and surgical technique, a variety of neoplastic and non-neoplastic pancreatic lesions are increasingly encountered in clinical practice. The distinction of these lesions has significant therapeutic and prognostic implications. Herein, we review the major clinicoepidemiologic and pathologic features of ductal adenocarcinoma, pancreatic cystic neoplasia, pancreatic endocrine tumor, and related lesions. Emphasis is placed on frozen-section diagnosis and differential diagnostic features. Also, potential diagnostic pitfalls are highlighted, such that they may be avoided. [ABSTRACT FROM AUTHOR]

Objective: To correlate survival and surgical-pathologic factors with DNA mismatch repair status in patients with endometrial cancer. Methods: Specimens from 336 patients with endometrial cancer were used to create a tissue microarray. Immunohistochemistry with antibodies against the mismatch repair genes MLH1, MSH2, MSH6, and PMS2 were used to stain the tissue microarray. Clinical, pathologic, and survival data were collected and correlated with the immunohistochemistry results. Results: Mismatch repair deficiency was seen in 29% (84 of 294) of cases. Correlation was noted between lack of expression of MLH1 and an increased risk for lymphvascular space involvement (32% versus 21%, P=.05) and cervical involvement (26% versus 14%, P=.02). Lack of expression of either MLH1 or MSH2 was associated with thinner patients (85% had a body mass index less than 40 versus 73% of patients with normal expression, P=.02), as well as with the absence of a history of previous primary malignancy (0 verus 13 cases [4%], P=.023). The estimated disease-free survival is 88%; despite a small number of recurrences, there was a nonsignificant improvement in disease-free survival in tumors with an intact mismatch repair system (P=.1). Significantly improved disease-free survival was seen in patients with normal MLH1 and MSH2 expression compared with those with abnormal expression (92% versus 81%, P=.035). Conclusion: Defects in DNA mismatch repair in endometrial cancer is correlated with negative prognostic factors and worse progression-free survival (without a difference in overall survival) compared with tumors with an intact mismatch repair system. Level Of Evidence: II-3. [ABSTRACT FROM AUTHOR]

Increased fruit and vegetable consumption is associated with decreased risk of a number of cancers of epithelial origin, including esophageal cancer. Dietary administration of lyophilized black raspberries (LBRs) has significantly inhibited chemically induced oral, esophageal, and colon carcinogenesis in animal models. Likewise, berry extracts added to cell cultures significantly inhibited cancer-associated processes. Positive results in preclinical studies have supported further investigation of berries and berry extracts in high-risk human cohorts, including patients with existing premalignancy or patients at risk for cancer recurrence. We are currently conducting a 6-mo chemopreventive pilot study administering 32 or 45 g (female and male, respectively) of LBRs to patients with Barrett's esophagus (BE), a premalignant esophageal condition in which the normal stratified squamous epithelium changes to a metaplastic columnar-lined epithelium. BE's importance lies in the fact that it confers a 30- to 40-fold increased risk for the development of esophageal adenocarcinoma, a rapidly increasing and extremely deadly malignancy. This is a report on interim findings from 10 patients. To date, the results support that daily consumption of LBRs promotes reductions in the urinary excretion of two markers of oxidative stress, 8-epi-prostaglandin F2alpha (8-Iso-PGF2) and, to a lesser more-variable extent, 8-hydroxy-2'-deoxyguanosine (8-OHdG), among patients with BE. [ABSTRACT FROM AUTHOR]

Background: Germ-line mutations in the mismatch-repair genes MLH1, MSH2, MSH6, and PMS2 lead to the development of the Lynch syndrome (hereditary nonpolyposis colorectal cancer), conferring a strong susceptibility to cancer. We assessed the frequency of such mutations in patients with colorectal cancer and examined strategies for molecular screening to identify patients with the syndrome. Methods: Patients with a new diagnosis of colorectal adenocarcinoma at the major hospitals in metropolitan Columbus, Ohio, were eligible for the study. Genotyping of the tumor for microsatellite instability was the primary screening method. Among patients whose screening results were positive for microsatellite instability, we searched for germ-line mutations in the MLH1, MSH2, MSH6, and PMS2 genes with the use of immunohistochemical staining for mismatch-repair proteins, genomic sequencing, and deletion studies. Family members of carriers of the mutations were counseled, and those found to be at risk were offered mutation testing. Results: Of 1066 patients enrolled in the study, 208 (19.5 percent) had microsatellite instability, and 23 of these patients had a mutation causing the Lynch syndrome (2.2 percent). Among the 23 probands with the Lynch syndrome, 10 were more than 50 years of age and 5 did not meet the Amsterdam criteria or the Bethesda guidelines for the diagnosis of hereditary nonpolyposis colorectal cancer (including the use of age and family history to identify patients at high risk for the Lynch syndrome). Genotyping for microsatellite instability alone and immunohistochemical analysis alone each failed to identify two probands. In the families of 21 of the probands, 117 persons at risk were tested, and of these, 52 had Lynch syndrome mutations and 65 did not. Conclusions: Routine molecular screening of patients with colorectal adenocarcinoma for the Lynch syndrome identified mutations in patients and their family members that otherwise would not have been detected. These data suggest that the effectiveness of screening with immunohistochemical analysis of the mismatch-repair proteins would be similar to that of the more complex strategy of genotyping for microsatellite instability. [ABSTRACT FROM AUTHOR]

Context.-Splenic rupture secondary to solid malignancy is an infrequent complication that usually occurs late in the progression of a previously diagnosed cancer. In rare instances, splenic rupture precipitates the discovery of an unsuspected pancreatic carcinoma. We report 2 cases of adenocarcinoma of the pancreas in which the patients presented with splenic rupture. Objectives.-To review the clinicopathologic features of splenic rupture due to pancreatic carcinoma and to increase awareness of malignancy as a possible etiology for atraumatic splenic rupture. Design.-We reviewed the clinical and pathologic data from 2 patients. A literature search was conducted to identify previous reports of splenic rupture associated with pancreatic cancer. We summarized the characteristics of the earlier cases and compared them with those of our patients. Results.-We found only 4 previous reports of splenic rupture preceding the diagnosis of pancreatic cancer. In 3 of these cases, the pancreatic carcinoma grossly invaded the spleen at the time of resection. In contrast, malignancy was not suspected as the etiology of the rupture in our patients until histologic examination of the resected spleen revealed carcinoma. Conclusion.-Splenic rupture is an unusual presentation of cancer of the pancreas, and to our knowledge only 4 cases have been reported previously in the literature. Although an underlying malignancy is relatively rare, spleens resected for atraumatic rupture should be carefully examined for possible neoplastic etiologies. [ABSTRACT FROM AUTHOR]

Context.--The distinction of metastatic breast adenocarcinoma (MBA) to the liver from hepatocellular carcinoma (HCC), cholangiocarcinoma (CC), and metastatic adenocarcinoma from other sites may require the use of immunohistochemistry. The use of antibodies directed against estrogen receptor (ER) and progesterone receptor (PR) has been suggested to help make this distinction. Objective.--To examine the utility of ER and PR immunohistochemistry in the distinction of MBA from HCC, CC, and other metastatic adenocarcinomas in the liver. Methods.--Ninety-two previously characterized hepatic neoplasms were identified, including HCC (n = 14), CC (n 5 16), and metastatic tumors from breast (n = 17), colorectal (n = 14), pancreatic (n = 15), and esophageal/gastric (n = 16) origins. For all cases of metastatic tumor, the primary tumor was reviewed to verify the diagnosis. All tumors were graded as well, moderately, or poorly differentiated. Estrogen receptor and PR immunohistochemical staining was performed on all cases and evaluated by 2 pathologists. Results.--Immunoreactivity for ER was identified only in MBA, with 6 (35%) of 17 cases positive. Positive immunoreactivity for PR was not restricted to MBA, but was seen in HCC, CC, esophageal/gastric, and pancreatic metastases. Positive immunostaining with PR was nearly as frequent in poorly differentiated carcinomas of nonbreast origin (3/16 cases, 19%) as in poorly differentiated breast carcinomas (2/8 cases, 25%). Conclusion.--Progesterone receptor exhibited poor specificity and sensitivity for the distinction of MBA from HCC, CC, and other metastatic adenocarcinomas. Estrogen receptor exhibited poor sensitivity for MBA, although the specificity was good. The finding that PR positivity was present with a similar frequency in poorly differentiated tumors of breast and nonbreast origin limits the usefulness of this marker. Therefore, ER and PR staining have limited utility in the distinction of MBA from HCC, CC, and other... [ABSTRACT FROM AUTHOR]

Inactivating mutations of Foxp3, the master regulator of regulatory T cell development and function, lead to immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome in mice and humans. IPEX is a fatal autoimmune disease, with allogeneic stem cell transplant being the only available therapy. In this study, we report that a single dose of adeno-associated virus (AAV)-IL-27 to young mice with naturally occurring Foxp3 mutation (Scurfy mice) substantially ameliorates clinical symptoms, including growth retardation and early fatality. Correspondingly, AAV-IL-27 gene therapy significantly prevented naive T cell activation, as manifested by downregulation of CD62L and upregulation of CD44, and immunopathology typical of IPEX. Because IL-27 is known to induce IL-10, a key effector molecule of regulatory T cells, we evaluated the contribution of IL-10 induction by crossing IL-10-null allele to Scurfy mice. Although IL-10 deficiency does not affect the survival of Scurfy mice, it largely abrogated the therapeutic effect of AAV-IL-27. Our study revealed a major role for IL-10 in AAV-IL-27 gene therapy and demonstrated that IPEX is amenable to gene therapy., (Copyright © 2024 by The American Association of Immunologists, Inc.)

MLH1 promoter hypermethylation (MPH) analysis is an essential step in the universal tumor testing algorithm for Lynch syndrome, the most common inherited predisposition to colorectal cancer (CRC). MPH usually indicates sporadic CRC. EPM2AIP1 gene shares the same promoter as MLH1, therefore MPH should also silence EPM2AIP1 transcription leading to loss of protein expression on immunohistochemistry (IHC). It has been previously reported that EPM2AIP1 IHC can be used as a surrogate for MPH in endometrial cancer. Our goal was to evaluate the feasibility of EPM2AIP1 IHC as a surrogate for MPH in CRC. 101 microsatellite instable CRC cases were selected, including 19 cases from whole tumor sections and 82 cases from tissue microarrays. 74 cases were with MPH and 27 without MPH. All 74 cases with MPH showed absent MLH1 by IHC, but only 47 (64%) exhibited loss of expression of EPM2AIP1. Of the 27 cases without MPH, 9 (33%) cases had unexpected loss of EPM2AIP1 expression. Of note, 10 cases were MLH1-mutated Lynch syndrome without MPH, and 2 of these cases showed unexpected loss of EPM2AIP1 staining. Of the 6 cases with double somatic mutations of MLH1 gene (without MPH), only 4 cases demonstrated intact expression of EPM2AIP1 as expected. Taken together, EPM2AIP1 loss was 64% sensitive and 67% specific for MPH, with an accuracy of 64%. We conclude that, unless stain quality improves with different clones or platforms, EPM2AIP1 IHC will likely not be useful as a surrogate test for MPH in CRC., Competing Interests: Declaration of competing interest The authors have no relevant conflicts of interest to report., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Context.—: Frozen sections are essential in the surgical management of patients, especially those with pancreatic masses, because frozen sections can provide answers intraoperatively and aid in treatment decisions. Pancreas frozen sections are challenging because of the small tissue size, processing artifacts, neoadjuvant treatment effects, and concurrent pancreatitis-like obstructive changes. The authors present a review of intraoperative evaluation of pancreatic specimens., Objectives.—: To provide an approach to the diagnosis of pancreatic adenocarcinoma on frozen sections and to discuss commonly encountered pitfalls. Indications for pancreas frozen sections and specific margin evaluation will be discussed. We will also review frozen section diagnosis of subcapsular liver lesions and tumors other than metastases of pancreatic ductal adenocarcinoma., Data Sources.—: Data sources included a literature review and the personal experiences of the authors., Conclusions.—: The features for diagnosis of pancreatic adenocarcinoma include disordered architecture, glands at abnormal locations, and atypical cytology. It is important to be aware of the pitfalls and clues on frozen section. The evaluation of resection margins can be challenging, and in the setting of the resection of cystic tumors, the key is the diagnosis of high-grade dysplasia or cancer. Finally, it is vital to remember the differential diagnosis for subcapsular liver lesions because not all lesions will be metastases of adenocarcinomas or bile duct adenomas. Frozen sections remain a useful tool for the intraoperative management of patients with pancreatic tumors., (© 2024 College of American Pathologists.)

Tumor budding refers to a cluster of one to four tumor cells located at the tumor-invasive front. While tumor budding is a prognostic factor for colorectal cancer, counting and grading tumor budding are time consuming and not highly reproducible. There could be high inter- and intra-reader disagreement on H&E evaluation. This leads to the noisy training (imperfect ground truth) of deep learning algorithms, resulting in high variability and losing their ability to generalize on unseen datasets. Pan-cytokeratin staining is one of the potential solutions to enhance the agreement, but it is not routinely used to identify tumor buds and can lead to false positives. Therefore, we aim to develop a weakly-supervised deep learning method for tumor bud detection from routine H&E-stained images that does not require strict tissue-level annotations. We also propose Bayesian Multiple Instance Learning (BMIL) that combines multiple annotated regions during the training process to further enhance the generalizability and stability in tumor bud detection. Our dataset consists of 29 colorectal cancer H&E-stained images that contain 115 tumor buds per slide on average. In six-fold cross-validation, our method demonstrated an average precision and recall of 0.94, and 0.86 respectively. These results provide preliminary evidence of the feasibility of our approach in improving the generalizability in tumor budding detection using H&E images while avoiding the need for non-routine immunohistochemical staining methods.

Current deep learning methods in histopathology are limited by the small amount of available data and time consumption in labeling the data. Colorectal cancer (CRC) tumor budding quantification performed using H&E-stained slides is crucial for cancer staging and prognosis but is subject to labor-intensive annotation and human bias. Thus, acquiring a large-scale, fully annotated dataset for training a tumor budding (TB) segmentation/detection system is difficult. Here, we present a DatasetGAN-based approach that can generate essentially an unlimited number of images with TB masks from a moderate number of unlabeled images and a few annotated images. The images generated by our model closely resemble the real colon tissue on H&E-stained slides. We test the performance of this model by training a downstream segmentation model, UNet++, on the generated images and masks. Our results show that the trained UNet++ model can achieve reasonable TB segmentation performance, especially at the instance level. This study demonstrates the potential of developing an annotation-efficient segmentation model for automatic TB detection and quantification.

Colorectal cancer (CRC) is the third most common cancer in the United States. Tumor Budding (TB) detection and quantification are crucial yet labor-intensive steps in determining the CRC stage through the analysis of histopathology images. To help with this process, we adapt the Segment Anything Model (SAM) on the CRC histopathology images to segment TBs using SAM-Adapter. In this approach, we automatically take task-specific prompts from CRC images and train the SAM model in a parameter-efficient way. We compare the predictions of our model with the predictions from a trained-from-scratch model using the annotations from a pathologist. As a result, our model achieves an intersection over union (IoU) of 0.65 and an instance-level Dice score of 0.75, which are promising in matching the pathologist's TB annotation. We believe our study offers a novel solution to identify TBs on H&E-stained histopathology images. Our study also demonstrates the value of adapting the foundation model for pathology image segmentation tasks.

With advancements in the field of digital pathology, there has been a growing need to compare the diagnostic abilities of pathologists using digitized whole slide images against those when using traditional hematoxylin and eosin (H&E)-stained glass slides for primary diagnosis. One of the most common specimens received in pathology practices is an endoscopic gastric biopsy with a request to rule out Helicobacter pylori (H. pylori) infection. The current standard of care is the identification of the organisms on H&E-stained slides. Immunohistochemical or histochemical stains are used selectively. However, due to their small size (2-4 μm in length by 0.5-1 μm in width), visualization of the organisms can present a diagnostic challenge. The goal of the study was to compare the ability of pathologists to identify H. pylori on H&E slides using a digital platform against the gold standard of H&E glass slides using routine light microscopy. Diagnostic accuracy rates using glass slides vs digital slides were 81% vs 72% (P = .0142) based on H&E slides alone. When H. pylori immunohistochemical slides were provided, the diagnostic accuracy was significantly improved to comparable rates (96% glass vs 99% digital, P = 0.2199). Furthermore, differences in practice settings (academic/subspecialized vs community/general) and the duration of sign-out experience did not significantly impact the accuracy of detecting H. pylori on digital slides. We concluded that digital whole slide images, although amenable in different practice settings and teaching environments, does present some shortcomings in accuracy and precision, especially in certain circumstances and thus is not yet fully capable of completely replacing glass slide review for identification of H. pylori. We specifically recommend reviewing glass slides and/or performing ancillary stains, especially when there is a discrepancy between the degree of inflammation and the presence of microorganisms on digital images., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Endoscopic biopsies from the ampulla of Vater are challenging due to specimen sampling limitation, small size, interventional artifacts, and the nature of local complex anatomy. We retrospectively reviewed 318 in-house ampulla of Vater biopsy specimens from 252 patients over a 10-year period. The biopsy findings were compared to those in subsequent biopsy and/or resection specimens. Of the 318 biopsy cases, 104 (32.7 %) cases were diagnosed as adenoma (96 with low-grade dysplasia; 8 with high-grade dysplasia), 19 (6.0 %) adenocarcinomas (ampullary-12, distal bile duct-6, pancreatic-1), 5 (1.6 %) other carcinomas/tumors, and the rest were benign findings (unremarkable, ulcer and acute inflammation, reactive changes, and rare atypical cells/gland). Of the 90 cases with follow-up specimens, 55 cases (61.1 %) had concordant results and 35 (38.9 %) were discordant. Eight (22.9 %) of the 35 discordant cases had major discrepancies (benign biopsy diagnosis with malignant resection diagnosis); 27 (77.1 %) cases had minor discrepancies (normal, reactive, atypical, and dysplastic). We found that vast majority of the false negative biopsy results were due to sampling limitations. Combined biopsy and cytology specimens may help decrease the false negative rate. Careful correlation with endoscopic/cytology/clinical findings and acknowledging the limitation of the biopsy material in the pathology report are important, when malignancy is suspected but cannot be established in a small ampullary biopsy., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Mismatch repair (MMR) protein-deficient non-neoplastic colonic crypts and endometrial glands (dMMR crypts and glands) have been reported as a unique marker of underlying Lynch syndrome (LS). However, no large studies have directly compared the frequency of detection in cases with double somatic (DS) MMR mutations. We retrospectively analyzed 42 colonic resection specimens (24 LS and 18 DS) and 20 endometrial specimens (9 LS and 11 DS), including 19 hysterectomies and 1 biopsy for dMMR crypts and glands. All specimens were from patients with known primary cancers, including colonic adenocarcinomas and endometrial endometrioid carcinomas (including 2 mixed carcinomas). Four blocks of normal mucosa away from the tumor were selected from most cases, as available. MMR immunohistochemistry specific to the primary tumor mutations was analyzed. dMMR crypts were found in 65% of LS and 0% of DS MMR-mutated colonic adenocarcinomas (P < .001). Most dMMR crypts were detected in the colon (12 of 15) compared to the ileum (3 of 15). dMMR crypts showed single and grouped losses of MMR immunohistochemical expression. dMMR glands were found in 67% of LS and 9% (1 of 11) of DS endometrial cases (P = .017). Most dMMR glands were found in the uterine wall, with 1 LS and 1 DS case exhibiting dMMR glands in the lower uterine segment. Most cases exhibited multifocal and grouped dMMR glands. No morphologic atypia was identified in dMMR crypts or glands. Overall, we demonstrate that dMMR crypts and glands are highly associated with underlying LS, while being rarer in those with DS MMR mutations., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Universal tumor screening (UTS) for Lynch syndrome (LS) on colorectal cancer (CRC) can be performed on biopsies or resection specimens. The advantage of biopsies is the chance to provide preoperative genetic counseling/testing (GC/T) so patients diagnosed with LS can make informed decisions regarding resection extent. We evaluated utilization of UTS on biopsies, percentage of patients with deficient mismatch repair (dMMR) who underwent GC/T preoperatively, and whether surgical/treatment decisions were impacted. We performed a retrospective review of medical records to assess CRC cases with dMMR immunohistochemical staining from 1/1/2017 to 2/26/2021. 1144 CRC patients had UTS using MMR immunohistochemistry; 559 biopsies (48.9%) and 585 resections (51.1%). The main reason UTS was not performed on biopsy was it occurred outside our health system. 58 (5%) of CRCs were dMMR and did not have MLH1 promoter hypermethylation (if MLH1 and PMS2 absent). 28/58 (48.3%) of dMMR cases were diagnosed on biopsy. Of those 28, 14 (50%) eventually underwent GC/T, and 7 (25%) had GT results prior to surgery. One of the 7 had incomplete documentation of results affecting their treatment plan. Of the remaining 6 with complete documentation, 5 underwent surgery and one was treated with immunotherapy only. Three patients elected a more extensive surgery. 6/28 (21.4%) dMMR patients identified on biopsy made an informed surgical/treatment decision based on their dMMR status/LS diagnosis. When applied, UTS on biopsy followed by genetic counseling and testing informs surgical decision-making. Process and implementation strategies are in place to overcome challenges to more broadly optimize this approach., (© 2022. The Author(s).)

Background: Resistance to anti-angiogenic therapies targeting vascular endothelial growth factor-A (VEGF-A) stems from VEGF-A independent angiogenesis mediated by other proangiogenic factors. Therefore identifying these factors in colon adenocarcinoma (CA) will reveal new therapeutic targets., Methods: Neuropeptide Y (NPY) and Y2 receptor (Y2R) expressions in CA were studied by immunohistochemical analysis. Orthotopic HT29 with intact VEGF-A gene and VEGF-A knockdown (by CRISPR/Cas9 gene-editing technique) HT29 colon cancer-bearing mice were treated with specific Y2R antagonists, and the effects on angiogenesis and tumour growth were studied. The direct effect of NPY on angiogenesis and the underlying molecular mechanism was elucidated by the modulation of Y2R receptors expressed on colonic endothelial cells (CEC)., Results: The results demonstrated that NPY and Y2R are overexpressed in human CA, orthotopic HT29, and most interestingly in VEGF-A-depleted orthotopic HT29 tumours. Treatment with Y2R antagonists inhibited angiogenesis and thereby HT29 tumour growth. Blocking /silencing Y2R abrogated NPY-induced angiogenic potential of CEC. Mechanistically, NPY regulated the activation of the ERK/MAPK signalling pathway in CEC., Conclusions: NPY derived from cancer cells independently regulates angiogenesis in CA by acting through Y2R present on CEC. Targeting NPY/Y2R thus emerges as a novel potential therapeutic strategy in CA., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

Importance: National guidelines endorse treatment with neoadjuvant therapy for borderline resectable pancreatic ductal adenocarcinoma (PDAC), but the optimal strategy remains unclear., Objective: To compare treatment with neoadjuvant modified FOLFIRINOX (mFOLFIRINOX) with or without hypofractionated radiation therapy with historical data and establish standards for therapy in borderline resectable PDAC., Design, Setting, and Participants: This prospective, multicenter, randomized phase 2 clinical trial conducted from February 2017 to January 2019 among member institutions of National Clinical Trials Network cooperative groups used standardized quality control measures and included 126 patients, of whom 70 (55.6%) were registered to arm 1 (systemic therapy; 54 randomized, 16 following closure of arm 2 at interim analysis) and 56 (44.4%) to arm 2 (systemic therapy and sequential hypofractionated radiotherapy; all randomized before closure). Data were analyzed by the Alliance Statistics and Data Management Center during September 2021., Interventions: Arm 1: 8 treatment cycles of mFOLFIRINOX (oxaliplatin, 85 mg/m2; irinotecan, 180 mg/m2; leucovorin, 400 mg/m2; and infusional fluorouracil, 2400 mg/m2) over 46 hours, administered every 2 weeks. Arm 2: 7 treatment cycles of mFOLFIRINOX followed by stereotactic body radiotherapy (33-40 Gy in 5 fractions) or hypofractionated image-guided radiotherapy (25 Gy in 5 fractions). Patients without disease progression underwent pancreatectomy, which was followed by 4 cycles of treatment with postoperative FOLFOX6 (oxaliplatin, 85 mg/m2; leucovorin, 400 mg/m2; bolus fluorouracil, 400 mg/m2; and infusional fluorouracil, 2400 mg/m2 over 46 hours)., Main Outcomes and Measures: Each treatment arm's 18-month overall survival (OS) rate was compared with a historical control rate of 50%. A planned interim analysis mandated closure of either arm for which 11 or fewer of the first 30 accrued patients underwent margin-negative (R0) resection., Results: Of 126 patients, 62 (49%) were women, and the median (range) age was 64 (37-83) years. Among the first 30 evaluable patients enrolled to each arm, 17 patients in arm 1 (57%) and 10 patients in arm 2 (33%) had undergone R0 resection, leading to closure of arm 2 but continuation to full enrollment in arm 1. The 18-month OS rate of evaluable patients was 66.7% (95% CI, 56.1%-79.4%) in arm 1 and 47.3% (95% CI 35.8%-62.5%) in arm 2. The median OS of evaluable patients in arm 1 and arm 2 was 29.8 (95% CI, 21.1-36.6) months and 17.1 (95% CI, 12.8-24.4) months, respectively., Conclusions and Relevance: This randomized clinical trial found that treatment with neoadjuvant mFOLFIRINOX alone was associated with favorable OS in patients with borderline resectable PDAC compared with mFOLFIRINOX treatment plus hypofractionated radiotherapy; thus, mFOLFIRINOX represents a reference regimen in this setting., Trial Registration: ClinicalTrials.gov Identifier: NCT02839343.

Context.—: Pancreatic adenocarcinoma is the third leading cause of cancer death in the United States. Surgery remains the mainstay of treatment, and frozen section analysis is used to confirm diagnosis and determine resectability and margin status., Objective.—: To evaluate use and accuracy of frozen section and how diagnosis impacts surgical procedure., Design.—: We reviewed patients with planned pancreatic resections between January 2014 and March 2019 with at least 1 frozen section. Pathology reports including frozen sections, preoperative cytology, and operative notes were reviewed. Frozen sections were categorized by margin, primary pancreatic diagnosis, metastasis, or vascular resectability. The deferral and error rates and surgeons' response were noted., Results.—: We identified 898 planned pancreatic resections and 221 frozen sections that were performed on 152 cases for 102 margins, 94 metastatic lesions, 20 primary diagnoses, and 5 to confirm vascular resectability. The diagnosis was deferred to permanent sections in 13 of 152 cases (8.6%) on 16 of 221 frozen sections (7.2%): 6 for metastasis, 8 for margins, and 2 for primary diagnosis. Discrepancies/errors were identified in 4 of 152 cases (2.6%) and 4 of 221 frozen sections (1.8%). Surgeons' responses were different than expected in 8 of 221 frozen sections (3.6%), but their actions were explained by other intraoperative findings in 6 of 8., Conclusions.—: Frozen section remains an important diagnostic tool used primarily for evaluation of margins and metastasis during pancreatectomy. In most cases, a definitive diagnosis is rendered, with occasional deferrals and few errors. Intraoperative findings explain most cases where surgeons act differently than expected based on frozen section diagnosis.

Purpose: To evaluate the use of early assessment of chemotherapy responsiveness by positron emission tomography (PET) imaging to tailor therapy in patients with esophageal and esophagogastric junction adenocarcinoma., Methods: After baseline PET, patients were randomly assigned to an induction chemotherapy regimen: modified oxaliplatin, leucovorin, and fluorouracil (FOLFOX) or carboplatin-paclitaxel (CP). Repeat PET was performed after induction; change in maximum standardized uptake value (SUV) from baseline was assessed. PET nonresponders (< 35% decrease in SUV) crossed over to the alternative chemotherapy during chemoradiation (50.4 Gy/28 fractions). PET responders (≥ 35% decrease in SUV) continued on the same chemotherapy during chemoradiation. Patients underwent surgery at 6 weeks postchemoradiation. Primary end point was pathologic complete response (pCR) rate in nonresponders after switching chemotherapy., Results: Two hundred forty-one eligible patients received Protocol treatment, of whom 225 had an evaluable repeat PET. The pCR rates for PET nonresponders after induction FOLFOX who crossed over to CP (n = 39) or after induction CP who changed to FOLFOX (n = 50) was 18.0% (95% CI, 7.5 to 33.5) and 20% (95% CI, 10 to 33.7), respectively. The pCR rate in responders who received induction FOLFOX was 40.3% (95% CI, 28.9 to 52.5) and 14.1% (95% CI, 6.6 to 25.0) in responders to CP. With a median follow-up of 5.2 years, median overall survival was 48.8 months (95% CI, 33.2 months to not estimable) for PET responders and 27.4 months (95% CI, 19.4 months to not estimable) for nonresponders. For induction FOLFOX patients who were PET responders, median survival was not reached., Conclusion: Early response assessment using PET imaging as a biomarker to individualize therapy for patients with esophageal and esophagogastric junction adenocarcinoma was effective, improving pCR rates in PET nonresponders. PET responders to induction FOLFOX who continued on FOLFOX during chemoradiation achieved a promising 5-year overall survival of 53%., Competing Interests: Karyn A. GoodmanConsulting or Advisory Role: RenovoRx Tanios Bekaii-SaabConsulting or Advisory Role: Amgen, Ipsen, Lilly, Bayer, Roche/Genentech, AbbVie, Incyte, Immuneering, Seattle Genetics, Pfizer, Boehringer Ingelheim, Janssen, Eisai, Daiichi Sankyo/UCB Japan, AstraZeneca, Exact Sciences, Natera, Treos Bio, Celularity, SOBI, BeiGene, Foundation MedicinePatents, Royalties, Other Intellectual Property: Patent WO/2018/183488 and Patent WO/2019/055687Other Relationship: Exelixis, Merck, AstraZeneca, Lilly, Pancreatic Cancer Action Network Daniel J. BoffaResearch Funding: Epic Sciences Wendy L. FrankelPatents, Royalties, Other Intellectual Property: Patent title: Automated Identification of Tumor Buds. Application No.: 16/230,118. Filing date: December 21, 2018. Publication date: July 4, 2019. Applicant(s): Ohio State Innovation Foundation, Columbus, OH. Inventor(s): Metin Gurcan, Winston-Salem, NC; Wendy Frankel, Columbus, OH; Wei Chen, Columbus, OH; Ahmad Fauzi and Mohammad Faizal, Selangor, MY Anne NoonanConsulting or Advisory Role: Helsinn Healthcare, QED Therapeutics, Exelixis, Eisai Yelena Y. JanjigianStock and Other Ownership Interests: RgenixConsulting or Advisory Role: Pfizer, Merck, Bristol Myers Squibb, Merck Serono, Daiichi Sankyo, Rgenix, Bayer, Imugene, AstraZeneca, Lilly, Zymeworks, Seattle Genetics, Merck Sharpe and Dohme Corp, Michael J. Hennessy Associates, Jounce Therapeutics, Ono PharmaceuticalResearch Funding: Boehringer Ingelheim, Bayer, Roche, Genentech, Rgenix, Bristol Myers Squibb, Merck, LillyOther Relationship: Paradigm, Clinical Care Options, Axis Medical Education, Research to Practice Paul J. ThurmesConsulting or Advisory Role: US OncologyTravel, Accommodations, Expenses: US Oncology Alan P. VenookConsulting or Advisory Role: Merck Sharp & Dohme, Array BioPharmaResearch Funding: Genentech/Roche, Bristol Myers Squibb, AmgenPatents, Royalties, Other Intellectual Property: Royalties from Now-UptoDate for authoring and maintaining two chaptersTravel, Accommodations, Expenses: Genentech, Roche Jeffrey A. MeyerhardtHonoraria: Cota Healthcare, Taiho PharmaceuticalResearch Funding: Boston Biomedical Eileen M. O'ReillyConsulting or Advisory Role: Merck, Agios, AstraZeneca, Bayer, BeiGene, Berry Genomics, Celgene, CytomX Therapeutics, Debiopharm Group, Eisai, Exelixis/Ipsen, Flatiron Health, Incyte, Janssen, LAM Therapeutics, Lilly, Loxo, Genentech/Roche, Minapharma, QED Therapeutics, RedHill Biopharma, Sillajen, SOBI, Yiviva, Autem Medical, Gilead Sciences, Ipsen, Silenseed, TheraBionic, twoXAR, Vector HealthResearch Funding: AstraZeneca/MedImmune, Acta Biologica, Bristol Myers Squibb, Celgene, Genentech, Halozyme, MabVax, Roche, Silenseed David H. IlsonConsulting or Advisory Role: Lilly/ImClone, Roche/Genentech, Bristol Myers Squibb, Pieris Pharmaceuticals, Merck, Bayer, AstraZeneca, Taiho Pharmaceutical, Astellas Pharma, IQvia, MacrogenicsNo other potential conflicts of interest were reported.

Hereditary cancer syndromes infer high cancer risks and require intensive surveillance. Identification of high-risk individuals among patients with colorectal cancer (CRC) needs improvement., Methods: Three thousand three hundred ten unselected adults who underwent surgical resection for primary invasive CRC were prospectively accrued from 51 hospitals across Ohio between January 1, 2013, and December 31, 2016. Universal Tumor screening (UTS) for mismatch repair (MMR) deficiency was performed for all, and pathogenic germline variants (PGVs) were identified using multigene panel testing (MGPT) in those who met at least one inclusion criterion: MMR deficiency, diagnosed < 50 years, multiple primary tumors (CRC or endometrial cancer), or with a first-degree relative with CRC or endometrial cancer., Results: Five hundred twenty-five patients (15.9%) had MMR deficiency. Two hundred thirty-four of 3,310 (7.1%; 16% of the 1,462 who received MGPT) had 248 PGVs in cancer susceptibility genes. One hundred forty-two (4.3%) had a PGV in an MMR gene, and 101 (3.1%) had a PGV in a non-MMR gene. Ten with Lynch syndrome (LS) also had a non-MMR PGV and were included in both groups. Two (0.06%) had constitutional MLH1 hypermethylation. Of unexplained MMR-deficient patients, 88.4% (76 of 86) had double somatic MMR mutations. Testing for only MMR genes in MMR-deficient patients would have missed 18 non-MMR gene PGVs (7.3% of total PGVs identified). Had UTS been the only method used to screen for hereditary cancer syndromes, 38.6% (91 of 236) would have been missed, including 6.3% (9 of 144) of those with LS. These results have treatment implications as 5.3% (175 of 3,310) had PGVs in genes with therapeutic targets., Conclusion: UTS alone is insufficient for identifying a large proportion of CRC patients with hereditary syndromes, including some with LS. At a minimum, 7.1% of individuals with CRC have a PGV and pan-cancer MGPT should be considered for all patients with CRC., Competing Interests: Heather Hampel Stock and Other Ownership Interests: Genome Medical Consulting or Advisory Role: InVitae, Genome Medical, Promega, 23andMe No other potential conflicts of interest were reported.Heather Hampel Stock and Other Ownership Interests: Genome Medical Consulting or Advisory Role: InVitae, Genome Medical, Promega, 23andMe No other potential conflicts of interest were reported., (© 2021 by American Society of Clinical Oncology.)

Aim: The prognostic significance of perineural invasion (PNI) in oesophageal adenocarcinoma (EAC) is unclear. We examined the association of PNI with clinical outcomes in patients treated with neoadjuvant chemoradiotherapy (nCRT) and surgery., Methods: We performed a single institutional retrospective study. We evaluated the association of PNI with locoregional recurrence-free survival (LRFS), distant metastasis-free survival, disease-free survival (DFS) and overall survival using log-rank and Cox proportional hazard modelling., Results: 29 out of 73 patients (40%) had PNI at the time of surgery. The median follow-up was 20.1 months. The median DFS was 18.4 months for patients with PNI vs 41.3 months for patients without PNI (p<0.05). The median LRFS was 23.3 months for patients with PNI and median not reached for patients without PNI (p<0.01). In a multivariate model including age and pathological variables, PNI remained a significant independent predictor of LRFS (HR 0.20, 95% CI 0.07 to 0.60; p=0.004)., Conclusions: For patients with EAC treated with nCRT, PNI found at the time of surgery is significantly associated with worse LRFS. Our data support attempts to validate this finding and perhaps testing the role of adjuvant therapy in patients with PNI., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Pancreatic ductal adenocarcinoma (PDAC) is aggressive, with an overall five-year survival rate of 9%, and few patients are candidates for pancreatectomy at presentation. The role of neoadjuvant therapy (NAT) is evolving, especially for high-risk potentially resectable tumors. Owing to the increasing number of NAT resection specimens, we aim to characterize the histologic changes associated with NAT and to compare two tumor regression grading schemes. One hundred eighteen resections for PDAC were selected from the cases between 2011 and 2018, 59 not treated and 59 treated with NAT. All H&E stained tumor slides were reviewed for histologic changes and graded using the four-tier modified Ryan score (recommended by College of American Pathologists) and the three-tier MD Anderson (MDA) score. The histologic changes evaluated included blue/grey fibrosis, islet cell hyperplasia, dystrophic calcification, amyloid deposition, cholesterol clefts, nerve hypertrophy, elastotic stromal/vascular change, abscess formation, and eosinophilic tumor cell changes. There were statistically significant differences for dystrophic calcification, eosinophilic tumor cell changes, elastotic stromal/vascular change, islet cell hyperplasia, and nerve hypertrophy between the two groups, with these features seen more frequently in NAT cases. Blue/grey stromal fibrosis was present in all cases regardless of NAT, except few complete regression cases and one treated case with intraneural invasion only. Blue/grey fibrosis is a useful histologic visual clue to suggest the possibility of adjacent tumor in the majority of PDAC cases regardless of NAT. By Kaplan-Meier analysis, neither grading scheme correlated with overall survival in our cohort. However, the MDA score was significantly correlated with both time to primary tumor recurrence (p = 0.002) and time to distant recurrence (p = 0.04), whereas the modified Ryan score was not., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Diagnostic testing of pancreatic cyst fluid obtained by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) has traditionally utilized elevated carcinoembryonic antigen (CEA) (≥192 ng/ml) and cytomorphologic examination to differentiate premalignant mucinous from benign pancreatic cystic lesions (PCLs). Molecular testing for KRAS/GNAS mutations has been shown to improve accuracy of detecting mucinous PCLs. Using a targeted next-generation sequencing (NGS) panel, we assess the status of PCL-associated mutations to improve understanding of the key diagnostic variables. Molecular analysis of cyst fluid was performed on 108 PCLs that had concurrent CEA and/or cytological analysis. A 48-gene NGS assay was utilized, which included genes commonly mutated in mucinous PCLs such as GNAS, KRAS, CDKN2A, and TP53. KRAS and/or GNAS mutations were seen in 59 of 68 (86.8%) cases with multimodality diagnosis of a mucinous PCL. Among 31 patients where surgical histopathology was available, the sensitivity, specificity, and diagnostic accuracy of NGS for the diagnosis of mucinous PCL was 88.5%, 100%, and 90.3%, respectively. Cytology with mucinous/atypical findings were found in only 29 of 62 cases (46.8%), with fluid CEA elevated in 33 of 58 cases (56.9%). Multiple KRAS mutations at different variant allele frequencies were seen in seven cases favoring multiclonal patterns, with six of them showing at least two separate PCLs by imaging. Among the 6 of 10 cases with GNAS + /KRAS- results, uncommon, non-V600E exon 11/15 hotspot BRAF mutations were identified. The expected high degree of accuracy of NGS detection of KRAS and/or GNAS mutations for mucinous-PCLs, as compared with CEA and cytological examination, was demonstrated. Multiple KRAS mutations correlated with multifocal cysts demonstrated by radiology. In IPMNs that lacked KRAS mutations, the concurring BRAF mutations with GNAS mutations supports an alternate mechanism of activation in the Ras pathway.

Objective: Lynch syndrome is the most common cause of inherited endometrial cancer, attributable to germline pathogenic variants (PV) in mismatch repair (MMR) genes. Tumor microsatellite instability (MSI-high) and MMR IHC abnormalities are characteristics of Lynch syndrome. Double somatic MMR gene PV also cause MSI-high endometrial cancers. The aim of this study was to determine the relative frequency of Lynch syndrome and double somatic MMR PV., Methods: 341 endometrial cancer patients enrolled in the Ohio Colorectal Cancer Prevention Initiative at The Ohio State University Comprehensive Cancer Center from 1/1/13-12/31/16. All tumors underwent immunohistochemical (IHC) staining for the four MMR proteins, MSI testing, and MLH1 methylation testing if the tumor was MMR-deficient (dMMR). Germline genetic testing for Lynch syndrome was undertaken for all cases with dMMR tumors lacking MLH1 methylation. Tumor sequencing followed if a germline MMR gene PV was not identified., Results: Twenty-seven percent (91/341) of tumors were either MSI-high or had abnormal IHC indicating dMMR. As expected, most dMMR tumors had MLH1 methylation; (69, 75.8% of the dMMR cases; 20.2% of total). Among the 22 (6.5%) cases with dMMR not explained by methylation, 10 (2.9% of total) were found to have Lynch syndrome (6 MSH6, 3 MSH2, 1 PMS2). Double somatic MMR PV accounted for the remaining 12 dMMR cases (3.5% of total)., Conclusions: Since double somatic MMR gene PV are as common as Lynch syndrome among endometrial cancer patients, paired tumor and germline testing for patients with non-methylated dMMR tumor may be the most efficient approach for LS screening., Competing Interests: Declaration of Competing Interest Professor Hampel is on the scientific advisory board for Genome Medical, InVitae Genetics, and Promega, and has had research support from Myriad Genetics Laboratories, Inc. Ms. Pearlman has had research support from Myriad Genetics Laboratories, Inc. Dr. Pritchard consults for Promega and AstraZeneca. Dr. Stanich receives research support from Emtora Biosciences, Janssen Pharmaceuticals Inc., Pfizer Inc. and the PTEN Research Foundation. Drs. Backes, Chen, Cohn, Copeland, Cosgrove, de la Chapelle, Frankel, Fowler, Jones, McElroy, O'Malley, Salani, Suarez, Yilmaz, and Zhao have no conflicts of interest to disclose., (Copyright © 2020 Elsevier Inc. All rights reserved.)

It has been observed that some patients with colorectal cancer due to germline or double somatic pathogenic variants in the mismatch repair (MMR) genes may have intact protein expression in their tumors as assessed by immunohistochemistry (IHC). This has been speculated to occur more frequently in Lynch syndrome (LS) cases due to pathogenic missense mutations, leading to expression of a full-length but nonfunctional protein with retained antigenicity. Our goals were to study the frequency of unexpected MMR expression in colorectal cancers among LS cases with missense mutations, LS cases with truncating mutations, as well as cases with double somatic MMR mutations and evaluate if the unexpected MMR expression is more common in certain categories. IHC slides were available for 82 patients with MMR deficiency without methylation, which included 56 LS cases and 26 double somatic MMR mutation cases. Sixteen of 82 MMR-defective cases showed unexpected MMR expression, with 10 cases showing tumor staining weaker than the control and 6 cases (7%) showing intact staining. Unexpected MMR expression was most commonly seen with LS cases with missense mutations (4 of 9, 44%), followed by MMR double somatic mutation cases (7 of 26, 27%), and finally by LS cases with truncating mutations (5 of 47, 11%). Cautious interpretation of MMR IHC is advised when dealing with tumor staining that is weaker than the control regardless of the percentage of tumor staining as these cases may harbor pathogenic MMR gene mutations. Missense mutations may account for some LS cases that may be missed by IHC alone. Strict adherence to proper interpretation of IHC with attention to staining intensity and the status of heterodimer partner protein will prevent many potential misses., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Aims: Immune checkpoint inhibitors (ICIs) have revolutionised the treatment of advanced malignancies by boosting immune-mediated destruction of neoplastic cells, but are associated with side effects stemming from generalised immune system activation against normal tissues. Checkpoint ligand expression in non-tumoral cells of tissues affected by immune-related adverse effects has been described in ICI-associated hypophysitis, myocarditis, and acute interstitial nephritis. We aimed to investigate the tissue expression of the immune checkpoint receptor programmed cell death-1 (PD-1) and its ligand, programmed death-ligand 1 (PD-L1), in PD-1 inhibitor-associated colitis (PD1i colitis)., Methods and Results: PD-1 and PD-L1 immunohistochemical expression levels were analysed in 15 cases of PD1i colitis and potential mimics-infectious colitis and inflammatory bowel disease (IBD). Increased epithelial expression of PD-L1 was observed in PD1i colitis as compared with normal colon and infectious colitis, but the expression level was lower than that in IBD. Conversely, PD-1 expression in inflammatory cells was higher in infectious colitis, intermediate in IBD, and minimal or absent in normal colon and in patients receiving PD-1 inhibitors., Conclusions: Although our results do not justify the use of PD-L1 as a discriminatory marker of PD1i colitis against other entities within the differential diagnosis, they support the concept that PD1i colitis and IBD have similar pathogenetic mechanisms. They also highlight the fact that PD-L1 epithelial overexpression is a commonly used mechanism of the gastrointestinal tract mucosa to protect itself from inflammatory-mediated damage resulting from different aetiologies, which probably underpins the high incidence of gastrointestinal immune-related adverse effects in patients receiving ICI therapies, in whom this mechanism is disrupted., (© 2020 John Wiley & Sons Ltd.)

We conducted an institutional study to compare the clinical and pathological efficacy between the neoadjuvant therapy (NAT)-modified FOLFIRINOX (mFOLF) vs nanoparticle albumin-bound paclitaxel plus gemcitabine (nab-P/G) for borderline resectable pancreatic cancer (BRPC) and locally advanced pancreatic cancer (LAPC) patients who completed resection. The study retrospectively enrolled patients with pathologically confirmed BRPC or LAPC from 2010 to 2018 at our institution. The survival rates were determined by the Kaplan-Meier method and log-rank test was used to test differences. Cox's proportional hazard model was used to assess survival with respect to covariates. Seventy-two patients who completed at least two cycles of neoadjuvant chemotherapy and surgical resection were included, with 52 (72.2%) patients receiving mFOLF and 20 (27.8%) receiving nab-P/G. Patients treated with mFOLF had statistically higher rates of RECIST 1.1 partial or complete response (16/52 vs 1/20, P = .028). Additionally, mFOLF patients had greater pathological tumor size reduction, fewer positive lymph nodes, and higher treatment response grade compared to the nab-P/G patients (all P < .05). The median overall survival was 33.3 months vs 27.1 months (P = .105), and distant metastasis-free survival (DMFS) was 21.3 months vs 14.6 months (P = .042) in the mFOLF vs nab-P/G groups, respectively. On multivariate analysis, mFOLF (hazard ratio, 0.428; 95% confidence interval [CI], 0.186-0.987) and abnormal postoperative CA 19-9 (hazard ratio, 2.47; 95% CI, 1.06-5.76) were associated with DMFS. Among patients with BRPC and LAPC who complete surgical resection, neoadjuvant mFOLF was associated with improved pathological and clinical outcomes compared with nab-P/G., (© 2020 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

Smooth muscle tumors represent the second most common mural mesenchymal neoplasm in the gastrointestinal tract, but established criteria for prognostic assessment of these tumors are lacking. A large cohort of surgically resected intramural gastrointestinal smooth muscle tumors from 31 institutions was analyzed to identify potential prognostic features. Pathologic features were assessed by expert gastrointestinal and/or soft tissue pathologists at each center. Immunohistochemical confirmation was required. A total of 407 cases from the esophagus (n = 97, 24%), stomach (n = 180, 44%), small bowel (n = 74, 18%), and colorectum (n = 56, 14%) were identified. Patients ranged in age from 19 to 92 years (mean 55 years), with a slight female predominance (57%). Mean tumor size was 5.4 cm, with the largest tumor measuring 29 cm. Disease progression following surgery, defined as local recurrence, metastasis, or disease-related death, occurred in 56 patients (14%). Colorectal tumors were most likely to progress, followed by small bowel and gastric tumors. None of the esophageal tumors in this series progressed. Receiver operator characteristic analysis identified optimal cutoffs of 9.8 cm and 3 mitoses/5 mm 2 for discriminating between progressive and non-progressive tumors. Histologic features strongly associated with progression by univariate analysis included moderate-to-severe atypia, high cellularity, abnormal differentiation (defined as differentiation not closely resembling that of normal smooth muscle), tumor necrosis, mucosal ulceration, lamina propria involvement, and serosal involvement (P < 0.0001 for all features). Age, sex, and margin status were not significantly associated with progression (P = 0.23, 0.82, and 0.07, respectively). A risk assessment table was created based on tumor site, size, and mitotic count, and Kaplan-Meier plots of progression-free survival for each subgroup revealed progression-based tiers. Based on our findings, it appears that nonesophageal gastrointestinal smooth muscle tumors measuring >10 cm and/or showing ≥3 mitoses/5 mm 2 may behave aggressively, and therefore close clinical follow-up is recommended in these cases.

Resectable pancreatic adenocarcinoma (PC) is generally managed with surgery followed by chemotherapy, but the role of postoperative chemoradiation (pCRT) is controversial. We sought to identify a microRNA (miRNA) expression profile associated with higher risk for local-regional recurrence (LRR), which might help identify patients that may benefit from pCRT. Total RNA was isolated from viable tumor from 88 patients who underwent PC resection with or without chemotherapy, but did not receive radiation. Digital miRNA expression profiling was performed and risk scores were calculated based on the expression levels of the four most significantly correlated miRNAs, and dichotomized about the median to detect correlations between risk group, LRR and overall survival (OS). Two cohorts from The Cancer Genome Atlas (TCGA) and Seoul National University (SNU) were used for validation. Patients with high-risk scores had significantly worse LRR ( p = 0.001) and worse OS ( p = 0.034). Two-year OS rates for the high- and low-risk groups were 27.7% and 52.2%, respectively. On multivariable analysis, the risk score remained significantly associated with LRR ( p = 0.018). When validated on TCGA data, a high-risk score was associated with worse OS on univariate ( p = 0.03) and multivariable analysis ( p = 0.017). When validated on the SNU cohort, a high-risk score was likewise associated with worse OS ( p = 0.042). We have developed a 4-miRNA molecular signature that is associated with risk of LRR and OS after PC resection and validated on two separate cohorts. This signature has the potential to select patients most likely to benefit from pCRT, and should be tested further., Competing Interests: CONFLICTS OF INTEREST No potential conflicts of interest., (Copyright: © 2020 Wolfe et al.)

Mismatch repair protein (MMR) immunohistochemistry is an important tool in screening for Lynch syndrome in colorectal cancer patients. Unusual staining patterns such as heterogeneous MSH6 staining have been reported in colorectal and endometrial cancers. We aim to better understand MSH6 staining heterogeneity in colorectal cancer by comparative sequencing of different tumor areas for MMR and DNA polymerase mutations. Whole-section slides of 1754 colorectal cancers were reviewed for heterogeneous MSH6 staining, defined as discrete tumor areas with abrupt loss of staining juxtaposed to tumor areas with retained staining. Nine cases (0.05%) demonstrated heterogeneous MSH6 staining; none received neoadjuvant therapy prior to the specimen collection. The area of tumor with loss of MSH6 expression ranged from 5% to 60% (average 22%). Four cases had enough tissue remaining in both retained and lost MSH6 areas to perform tumor sequencing on both areas. All 9 cases were negative for MSH6 germline mutation; MSH6 heterogeneous staining was seen in tumors with MLH1 or PMS2 abnormalities (6 cases of MLH1 methylation, 2 PMS2 germline mutation, 1 MLH1 germline mutation). In addition, case 1 also had a somatic POLD1 exonuclease domain mutation (p.Y405C) in the MSH6 loss area but not in the intact area. We recommend reporting MSH6 heterogeneous pattern as MSH6 staining is present with a comment stating that the heterogeneous pattern typically does not indicate germline mutation in MSH6 but is commonly associated with abnormality in another MMR gene such as MLH1 or PMS2, or even other DNA repair genes such as DNA polymerase., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Tumor budding is defined as the presence of single tumor cells or small tumor clusters (less than five cells) that 'bud' from the invasive front of the main tumor. Tumor budding (TB) has recently emerged as an important adverse prognostic factor for many different cancer types. In colorectal carcinoma (CRC), tumor budding has been independently associated with lymph node metastasis and poor outcome. Pathologic assessment of tumor budding by light microscopy requires close evaluation of tumor invasive front on intermediate to high power magnification, entailing locating the 'hotspot' of tumor budding, counting all TB in one high power field, and generating a tumor budding score. By automating these time-consuming tasks, computer-assisted image analysis tools can be helpful for daily pathology practice, since tumor budding reporting is now recommended on select cases. In this paper, we report our work on the development of a tumor budding detection system in CRC from whole-slide Cytokeratin AE1/3 images, based on de novo computer algorithm that automates morphometric analysis of tumor budding.

Background: Atypical multinucleated stromal giant cells (MSGCs) are occasionally encountered in the esophagogastric mucosa. This study aims to investigate the origin and clinical association of MSGCs in the upper gastrointestinal tract., Methods: Three hundred sixty-one contiguous biopsies and 1 resection specimen from the stomach and gastroesophageal junction (GEJ) were identified from archives for morphologic and immunohistochemical studies., Results: MSGCs were identified in 22 cases (6%: 7 gastric, 15 GEJ). Patients' average age was 53 years. There was no sex predilection. 77% cases had only 1 or 2 MSGCs per 10 high power fields. MSGCs were located in the lamina propria of the gastric or GEJ mucosa, with an accentuation in the subepithelial zone. The median number of nuclei in a MSGC was 5 (ranging from 3 to 16). The nuclei were touching/overlapping, often arranged into "wreath", "caterpillar", or "morula" configurations. MSGCs expressed smooth muscle actin, desmin, while negative for cytokeratin AE1/3, CD68, S100, chromogranin, and CD117. The most common clinical history was epigastric pain, gastroesophageal reflux, and Barrett esophagus. The most common associated pathologic diagnoses included reactive (chemical) gastropathy (71% gastric biopsies) and gastroesophageal reflux (73% GEJ specimens)., Conclusions: MSGCs in the esophagogastric mucosa show smooth muscle/myofibroblast differentiation by immunohistochemistry and likely represent a reactive/reparative stromal reaction associated with gastroesophageal reflux and reactive (chemical) gastropathy.