Prognostic performance of microscopic size measurements in small invasive carcinomas arising in intraductal papillary mucinous neoplasms of the pancreas.

AIMS: Small invasive carcinomas arising in intraductal papillary mucinous neoplasms (IPMNs) of the pancreas can present as multiple, small foci. In such cases, there is no clear optimal measurement method for determining the invasive size for tumour staging and prognostication. METHODS: In all, 117 small invasive IPMNs (size of largest invasive component ≤2 cm) from seven institutions (2000-2016) were reviewed, and all individual foci of invasive carcinoma were measured. T stages (AJCC 8th edition) based on the largest single focus size (LS), average size of all foci (AS), and total sum of all foci (TS) were examined in association with clinicopathologic parameters and patient outcomes. RESULTS: The cohort comprised IPMNs with invasive tubular-type (n = 82, 70%) and colloid-type (n = 35, 30%) carcinomas. The mean LS, AS, and TS were 0.86, 0.71, and 1.32 cm, respectively. Based on the LS, AS, and TS, respectively, 48, 65, and 39 cases were classified as pT1a; 22, 18, and 11 cases as pT1b; and 47, 34, and 50 cases as pT1c. Higher pT stages based on all measurements were significantly associated with small vessel, large vessel, and perineural invasion (P < 0.05). LS-, AS-, and TS-based pT stages were not significantly associated with recurrence-free survival (RFS) or overall survival (OS) by univariate or multivariate analyses. However, among tubular-type carcinomas, higher LS-, AS-, and TS-based pT stages trended with lower RFS (based on 1-, 3-, and 5-year survival rates). All microscopic measurement methods were most predictive of RFS and OS using a 1.5-cm cutoff, with LS significantly associated with both RFS and OS by univariate and multivariate analysis. CONCLUSIONS: For invasive tubular-type carcinomas arising in IPMN, microscopic size-based AJCC pT stages were not significant predictors of patient outcomes. However, for LS, a size threshold of 1.5 cm was optimal for stratifying both RFS and OS. The AJCC 8th ed. may not be applicable for stratifying small invasive IPMNs with colloid-type histology that generally portend a more favourable prognosis.

Inhibition of the proline metabolism rate-limiting enzyme P5CS allows proliferation of glutamine-restricted cancer cells.

Glutamine is a critical metabolite for rapidly proliferating cells as it is used for the synthesis of key metabolites necessary for cell growth and proliferation. Glutamine metabolism has been proposed as a therapeutic target in cancer and several chemical inhibitors are in development or in clinical trials. How cells subsist when glutamine is limiting is poorly understood. Here, using an unbiased screen, we identify ALDH18A1, which encodes P5CS, the rate-limiting enzyme in the proline biosynthetic pathway, as a gene that cells can downregulate in response to glutamine starvation. Notably, P5CS downregulation promotes de novo glutamine synthesis, highlighting a previously unrecognized metabolic plasticity of cancer cells. The glutamate conserved from reducing proline synthesis allows cells to produce the key metabolites necessary for cell survival and proliferation under glutamine-restricted conditions. Our findings reveal an adaptive pathway that cancer cells acquire under nutrient stress, identifying proline biosynthesis as a previously unrecognized major consumer of glutamate, a pathway that could be exploited for developing effective metabolism-driven anticancer therapies.

Molecular magnetic resonance imaging of liver inflammation using an oxidatively activated probe.

Background & Aims: Many liver diseases are driven by inflammation, but imaging to non-invasively diagnose and quantify liver inflammation has been underdeveloped. The inflammatory liver microenvironment is aberrantly oxidising owing in part to reactive oxygen species generated by myeloid leucocytes. We hypothesised that magnetic resonance imaging using the oxidatively activated probe Fe-PyC3A will provide a non-invasive biomarker of liver inflammation. Methods: A mouse model of drug-induced liver injury was generated through intraperitoneal injection of a hepatoxic dose of acetaminophen. A mouse model of steatohepatitis was generated via a choline-deficient, l-amino acid defined high-fat diet (CDAHFD). Images were acquired dynamically before and after intravenous injection of Fe-PyC3A. The contrast agent gadoterate meglumine was used as a non-oxidatively activated negative control probe in mice fed CDAHFD. The (post-pre) Fe-PyC3A injection change in liver vs. muscle contrast-to-noise ratio (ΔCNR) recorded 2 min post-injection was correlated with liver function test values, histologic scoring assigned using the NASH Clinical Research Network criteria, and intrahepatic myeloid leucocyte composition determined by flow cytometry. Results: For mice receiving i.p. injections of acetaminophen, intrahepatic neutrophil composition correlated poorly with liver test values but positively and significantly with ΔCNR (r = 0.64, p <0.0001). For mice fed CDAHFD, ΔCNR generated by Fe-PyC3A in the left lobe was significantly greater in mice meeting histologic criteria strongly associated with a diagnosis NASH compared to mice where histology was consistent with likely non-NASH (p = 0.0001), whereas no differential effect was observed using gadoterate meglumine. In mice fed CDAHFD, ΔCNR did not correlate strongly with fractional composition of any specific myeloid cell subpopulation as determined by flow cytometry. Conclusions: Magnetic resonance imaging using Fe-PyC3A merits further evaluation as a non-invasive biomarker for liver inflammation. Impact and implications: Non-invasive tests to diagnose and measure liver inflammation are underdeveloped. Inflammatory cells such as neutrophils release reactive oxygen species which creates an inflammatory liver microenvironment that can drive chemical oxidation. We recently invented a new class of magnetic resonance imaging probe that is made visible to the scanner only after chemical oxidation. Here, we demonstrate how this imaging technology could be applied as a non-invasive biomarker for liver inflammation.

Retroperitoneal Foregut Duplication Cyst Containing Gastric, Respiratory, and Pancreatic Tissue Misinterpreted as an Adrenal Mass on Imaging: A Case Report and Review of the Literature.

Foregut duplication cyst is most commonly seen in the posterior mediastinum without communication with adjacent organs or presence of other malformations and typically shows ectopic gastric or respiratory epithelium. The finding of ectopic pancreatic tissue is extremely rare. A 15-year-old female patient presented with elevated blood pressure, intermittent right flank pain for 18 months. An abdominal MRI revealed a 4 cm right cystic retroperitoneal mass, initially thought to arise from the right adrenal gland. Intraoperatively, the mass was centered in the retroperitoneum between the right adrenal gland and kidney, without attachments to these organs and no communication with other structures, and it was completely excised. Gross examination revealed a 3.5 cm well-circumscribed solid and cystic mass with orange-white cut surface and cloudy fluid surrounded by variable amounts of adipose tissue. On microscopic examination, the cysts were lined by respiratory and gastric antral/oxyntic-type mucosa, surrounded by muscularis mucosae, submucosal tissue, muscularis propria, and perienteric tissue. Within the muscular propria, exocrine pancreatic tissue was also noted. The patient is well with 7-months of follow up. This case is the first one reporting gastric, respiratory, and pancreatic epithelia.

Defining an abnormal p53 immunohistochemical stain in Barrett's oesophagus-related dysplasia: a single-positive crypt is a sensitive and specific marker of dysplasia.

AIMS: p53 is an independent risk stratification marker in Barrett's oesophagus (BE), but no universally accepted definition exists for abnormal p53 staining. Herein, we assess p53 stains in two cohorts to: (1) define abnormal p53 staining in BE-related dysplasia (BERD) and (2) assess the specificity and sensitivity of this cut-point for the diagnosis of dysplasia. METHODS: Cohort 1 (n = 313) included (1) dysplastic BE biopsies, (2) prior non-dysplastic BE (NDBE) biopsies from the same patients and (3) NDBE biopsies from patients who never progressed to dysplasia. Cohort 2 (n = 191) consisted of BE biopsies in which p53 staining aided in diagnosing dysplasia. Automated p53 staining quantification was performed on cohort 1. A semiquantitative p53 analysis, performed on both cohorts, included: (1) number of strongly positive glands, (2) strong glandular surface staining, (3) percentage of strongly positive glands and (4) null phenotype. RESULTS: NDBE biopsies from cohort 1 patients who progressed to dysplasia were more likely to show p53 positivity than non-progressors (16.9 versus 0.6%) (P = 0.0001). The optimal quantitative cut-point for distinguishing dysplastic from never-dysplasia biopsies was 10 strongly positive cells. By semiquantitative analysis, a single strongly p53-positive gland distinguished dysplastic from never-dysplasia BE (sensitivity 98.6%, specificity 99.4%). The semiquantitative and quantitative analyses correlated (P = 0.0001). In cohort 2, the sensitivity and specificity for BERD of ≥ 1 strongly positive p53 gland were 86.0 and 88.6%. CONCLUSIONS: A single strongly positive p53 gland is sensitive and specific for BERD. Automated p53 analysis may reduce subjectivity associated with the diagnosis of BERD.

A Novel Digital Algorithm for Identifying Liver Steatosis Using Smartphone-Captured Images.

Access to lifesaving liver transplantation is limited by a severe organ shortage. One factor contributing to the shortage is the high rate of discard in livers with histologic steatosis. Livers with <30% macrosteatosis are generally considered safe for transplant. However, histologic assessment of steatosis by a pathologist remains subjective and is often limited by image quality. Here, we address this bottleneck by creating an automated digital algorithm for calculating histologic steatosis using only images of liver biopsy histology obtained with a smartphone. Methods: Multiple images of frozen section liver histology slides were captured using a smartphone camera via the optical lens of a simple light microscope. Biopsy samples from 80 patients undergoing liver transplantation were included. An automated digital algorithm was designed to capture and count steatotic droplets in liver tissue while discounting areas of vascular lumen, white space, and processing artifacts. Pathologists of varying experience provided steatosis scores, and results were compared with the algorithm's assessment. Interobserver agreement between pathologists was also assessed. Results: Interobserver agreement between all pathologists was very low but increased with specialist training in liver pathology. A significant linear relationship was found between steatosis estimates of the algorithm compared with expert liver pathologists, though the latter had consistently higher estimates. Conclusions: This study demonstrates proof of the concept that smartphone-captured images can be used in conjunction with a digital algorithm to measure steatosis. Integration of this technology into the transplant workflow may significantly improve organ utilization rates.

Inhibition of microbial deconjugation of micellar bile acids protects against intestinal permeability and liver injury.

Altered host-microbe interactions and increased intestinal permeability have been implicated in disease pathogenesis. However, the mechanisms by which intestinal microbes affect epithelial barrier integrity remain unclear. Here, we investigate the impact of bacterial metabolism of host-produced bile acid (BA) metabolites on epithelial barrier integrity. We observe that rats fed a choline-deficient, l-amino acid-defined, high-fat diet (CDAHFD) exhibit reduced intestinal abundance of host-produced conjugated BAs at early time points, coinciding with increased gut permeability. We show that in vitro, conjugated BAs protect gut epithelial monolayers from damage caused by bacterially produced unconjugated BAs through micelle formation. We then demonstrate that inhibition of bacterial BA deconjugation with a small-molecule inhibitor prevents the development of pathologic intestinal permeability and hepatic inflammation in CDAHFD-fed rats. Our study identifies a signaling-independent, physicochemical mechanism for conjugated BA-mediated protection of epithelial barrier function and suggests that rational manipulation of microbial BA metabolism could be leveraged to regulate gut barrier integrity.

Clinical, pathological genetics and intratumoral immune milieu of serrated adenocarcinoma of the colon.

BACKGROUND: Serrated adenocarcinoma (SAC), a recognised WHO variant of colonic adenocarcinoma, is the purported end-product of serrated neoplasia. However, the diagnosis of SAC is infrequently rendered, and little is known about its prognosis, immune microenvironment and molecular alterations. MATERIALS AND METHODS: We assessed 903 consecutive colon carcinomas and recognised tumours with ≥ 5% (n = 77) serrated and ≥ 50% serrated patterns (n = 13). We assessed precursor polyps and synchronous polyps. We recorded demographic/clinical parameters, histological features and mismatch repair (MMR) status. We performed immunohistochemistry and quantification on tissue microarray for HLA class I/II proteins, B2MG, CD8, CD163, LAG3, FoxP3, PD-L1 and BRAF V600E. RESULTS: We identified ≥ 5% epithelial serration prevalence in 8.5% of cases and ≥ 50% epithelial serration prevalence in 1.4% of cases. Precursor lesions were present in 21.4% of cases; these were mostly tubular adenomas with two traditional serrated adenomas identified. SAC with ≥ 5% serrations exhibited lower numbers of CD8-positive lymphocytes (P = 0.002) and lower B2MG expression (P = 0.048), although neither value was significant at ≥ 50% serration threshold. There was no difference in HLA class I/II, or PD-L1 expression on tumour cells and no difference in PD-L1, LAG3, FoxP3 and CD163 expression on immune cells. There was no association with MMR status, or BRAFV600E relative to conventional adenocarcinoma. There was improved disease-specific survival on univariate (but not multivariate) analysis between carcinomas with serrated pattern and non-mucinous conventional colonic carcinomas at ≥ 5% epithelial serrations (P = 0.04). CONCLUSION: SAC category shows a limited impact on survival, and this phenotype may harbour a unique immunological milieu.

Atorvastatin favorably modulates a clinical hepatocellular carcinoma risk gene signature.

Lipophilic but not hydrophilic statins have been shown to be associated with reduced risk for hepatocellular carcinoma (HCC) in patients with chronic viral hepatitis. We investigated differential actions of lipophilic and hydrophilic statins and their ability to modulate a clinical prognostic liver signature (PLS) predicting HCC risk in patients with liver disease. Hepatitis C virus (HCV)-infected Huh7.5.1 cells, recently developed as a model to screen HCC chemopreventive agents, were treated with lipophilic statins (atorvastatin and simvastatin) and hydrophilic statins (rosuvastatin and pravastatin), and then analyzed by RNA sequencing and PLS. Lipophilic statins, particularly atorvastatin, more significantly suppressed the HCV-induced high-risk pattern of PLS and genes in YAP and AKT pathway implicated in fibrogenesis and carcinogenesis, compared with the hydrophilic statins. While atorvastatin inhibited YAP activation through the mevalonate pathway, the distinctive AKT inhibition of atorvastatin was mediated by stabilizing truncated retinoid X receptor alpha, which has been known to enhance AKT activation, representing a target for HCC chemoprevention. In addition, atorvastatin modulated the high-risk PLS in an in vitro model of nonalcoholic fatty liver disease (NAFLD). Conclusion: Atorvastatin distinctively inhibits YAP and AKT activation, which are biologically implicated in HCC development, and attenuates a high-risk PLS in an in vitro model of HCV infection and NAFLD. These findings suggest that atorvastatin is the most potent statin to reduce HCC risk in patients with viral and metabolic liver diseases.

Programmed death-ligand 1 expression in the immune compartment of colon carcinoma.

Programmed cell death ligand 1 (PD-L1) on tumor cells is a significant prognostic biomarker for a number of malignancies, although less is known about the significance of PD-L1 positive immune cells in colon carcinoma. The purpose of this study is to evaluate the role of PD-L1 in a large cohort of colon carcinomas to identify patterns of PD-L1 expression in the tumor microenvironment and its correlation with other key immune subsets to better understand the impact of these immune cells. We assessed 1218 colon carcinomas on representative tissue microarray sections, gathered relevant clinicopathologic information, and performed immunohistochemical staining for mismatch repair proteins, CD8, CD163, LAG3, PD-L1, FoxP3, and BRAF V600E. We then performed automated quantification; manual quantification was used for PD-L1 tumor cells and immune cells. Dual PD-L1/PU.1 immunostain was also performed. The majority of PD-L1 positive cells expressed PU.1 thus representing tumor-associated macrophages. Based on the median number of PD-L1 positive immune cells (7.6/mm2), we classified tumors into two classes: (1) PD-L1 immune cell low and (2) PD-L1 immune cell high. PD-L1 immune cell high colon carcinomas showed favorable prognostic pathologic features including less frequent extramural venous invasion (p = 0.0001) and lower AJCC stage (p = 0.0001); they were also more commonly associated with deficient mismatch repair (dMMR) (p = 0.0001) and BRAF V600E reactivity. PD-LI immune cell high tumors were associated with high CD8, CD163, and FoxP3 positive cells (p = 0.0001, respectively). PD-L1 immune cell high and LAG3 high colon carcinomas were associated with improved disease-specific survival (p = 0.0001 and 0.001, respectively). PD-L1 expression on tumor cells was not associated with disease-specific survival. On multivariate analysis of chemotherapy naïve stage 2 colon carcinomas, only extramural venous invasion (p = 0.002), perineural invasion (p = 0.001) and PD-L1 immune cell expression (p = 0.032) correlated with disease-specific survival. Resected colonic carcinomas with high expression of PD-L1 and LAG3 proteins on immune cells were associated with improved prognosis in colon carcinoma. The mechanism underlying the improved prognosis of colon carcinomas bearing high numbers of immunoregulatory cells needs further investigation.

Correlation of clinical, pathologic, and genetic parameters with intratumoral immune milieu in mucinous adenocarcinoma of the colon.

Mucinous adenocarcinoma (MAD), the most common subtype of colonic adenocarcinoma (CA), requires >50% intratumoral mucin. There is limited data regarding the impact of MAD on key lymphocyte subsets and therapeutically critical immune elements. In this study we address: (1) the definition of MAD, (2) grading of MAD, and (3) the impact of MAD and extracellular mucin on intratumoral immune milieu. Estimation of the percentage of intratumoral mucin was performed by two pathologists. Tissue microarrays were stained for immune markers including CD8, CD163, PD-L1, FoxP3, ß2 microglobulin, HLA class I, and HLA class II. Immunohistochemistry for BRAF V600E was performed. MMR status was determined on immunohistochemistry for MSH2, MSH6, MLH1, PMS2. Manual and automated HALO platforms were used for quantification. The 903 CAs included 62 (6.9%) MAD and 841 CA with ≤ 50% mucin. We identified 225 CAs with mucinous differentiation, defined by ≥10% mucin. On univariate analysis neither cut point, 50% (p = 0.08) and 10% (p = 0.08) mucin, correlated with disease-specific survival (DSS). There were no differences in key clinical, histological and molecular features between MAD and CA with mucinous differentiation. On univariate analysis of patients with MAD, tumor grade correlated with DSS (p = 0.0001) while MMR status did not (p = 0.86). There was no statistically significant difference in CD8 (P = 0.17) and CD163 (P = 0.05) positive immune cells between MAD and conventional CA. However, deficient (d) MMR MADs showed fewer CD8 (P = 0.0001), CD163 (P = 0.0001) and PD-L1 (P = 0.003) positive immune cells compared to proficient (p)MMR MADs, a finding also seen with at 10% mucin cut point. Although MAD does not impact DSS, this study raises the possibility that the immune milieu of dMMR MADs and tumors with > =10% mucin may differ from pMMR MADs and tumors with <10% mucin, a finding that may impact immune-oncology based therapeutics.

Agrin Loss in Barrett's Esophagus-Related Neoplasia and Its Utility as a Diagnostic and Predictive Biomarker.

PURPOSE: There is an unmet need for identifying novel biomarkers in Barrett's esophagus that could stratify patients with regards to neoplastic progression. We investigate the expression patterns of extracellular matrix (ECM) molecules in Barrett's esophagus and Barrett's esophagus-related neoplasia, and assess their value as biomarkers for the diagnosis of Barrett's esophagus-related neoplasia and to predict neoplastic progression. EXPERIMENTAL DESIGN: Gene-expression analyses of ECM matrisome gene sets were performed using publicly available data on human Barrett's esophagus, Barrett's esophagus-related dysplasia, esophageal adenocarcinoma (ADCA) and normal esophagus. Immunohistochemical expression of basement membrane (BM) marker agrin (AGRN) and p53 was analyzed in biopsies of Barrett's esophagus-related neoplasia from 321 patients in three independent cohorts. RESULTS: Differential gene-expression analysis revealed significant enrichment of ECM matrisome gene sets in dysplastic Barrett's esophagus and ADCA compared with controls. Loss of BM AGRN expression was observed in both Barrett's esophagus-related dysplasia and ADCA. The mean AGRN loss in Barrett's esophagus glands was significantly higher in Barrett's esophagus-related dysplasia and ADCA compared with non-dysplastic Barrett's esophagus (NDBE; P < 0.001; specificity = 82.2% and sensitivity = 96.4%). Loss of AGRN was significantly higher in NDBE samples from progressors compared with non-progressors (P < 0.001) and identified patients who progressed to advanced neoplasia with a specificity of 80.2% and sensitivity of 54.8%. Moreover, the combination of AGRN loss and abnormal p53 staining identified progression to Barrett's esophagus-related advanced neoplasia with a specificity and sensitivity of 86.5% and 58.7%. CONCLUSIONS: We highlight ECM changes during Barrett's esophagus progression to neoplasia. BM AGRN loss is a novel diagnostic biomarker that can identify patients with NDBE at increased risk of developing advanced neoplasia.

Concurrent Nab-paclitaxel and Radiotherapy: Novel Radiosensitization for Borderline Resectable or Unresectable Pancreatic Cancer.

PURPOSE: This study evaluates the toxicity and tumor response with concurrent nab-paclitaxel chemoradiotherapy (CRT) compared with standard (5-fluorouracil or gemcitabine) CRT. MATERIALS AND METHODS: Fifty patients with borderline resectable or unresectable pancreatic adenocarcinoma from 2014 to 2017 were divided into 2 groups: concurrent nab-paclitaxel (100 to 125 mg/m2 weekly) CRT (median: 2.1 Gy fraction size and 52.5 Gy total) or standard CRT (median: 1.8 Gy fraction size, 54.5 Gy total). The primary endpoint was toxicity, and secondary endpoints were local failure and conversion to resectability. Comparisons were made using rank-sum or Fisher exact test and multivariable competing risk regression for the cumulative incidence of local failure. RESULTS: There were 28 patients in the nab-paclitaxel CRT group and 22 in the standard CRT group; 88% had the unresectable disease. The median follow-up was 18 months. The median duration of chemotherapy before concurrent CRT was 1.9 and 2.3 months in the nab-paclitaxel and standard CRT groups (P=0.337), and radiotherapy dose was 52.5 Gy (range, 52.5 to 59.4 Gy) and 54.5 Gy (range, 45.0 to 59.4 Gy), respectively. There were no statistically significant grade ≥2 toxicities. The nab-paclitaxel CRT group experienced a nonstatistically significant lower incidence of local failure (hazard ratio=0.91, 95% confidence interval: 0.27-3.03, P=0.536). More patients in the nab-paclitaxel CRT group proceeded to surgery (9/28 compared with 3/22 in the standard CRT, P=0.186); of which 6 (25%) in the nab-paclitaxel CRT and 2 (10%) in the standard CRT groups were initially unresectable. CONCLUSIONS: Nab-paclitaxel CRT had similar toxicity compared with standard CRT in the treatment of borderline resectable or unresectable pancreatic cancer. Its use was associated with an arithmetically lower cumulative incidence of local failure and an arithmetically higher conversion to resectability, both of which were not statistically significant.

Fatty Acids Activate the Transcriptional Coactivator YAP1 to Promote Liver Fibrosis via p38 Mitogen-Activated Protein Kinase.

BACKGROUND & AIMS: Patients with simple steatosis (SS) and nonalcoholic steatohepatitis can develop progressive liver fibrosis, which is associated with liver-related mortality. The mechanisms contributing to liver fibrosis development in SS, however, are poorly understood. SS is characterized by hepatocellular free fatty acid (FFA) accumulation without lobular inflammation seen in nonalcoholic steatohepatitis. Because the Hippo signaling transcriptional coactivator YAP1 (YAP) has previously been linked with nonalcoholic fatty liver disease (NAFLD)-related fibrosis, we sought to explore how hepatocyte FFAs activate a YAP-mediated profibrogenic program. METHODS: We analyzed RNA sequencing data from a GEO DataSet (accession: GSE162694) consisting of 143 patients with NAFLD. We also performed immunohistochemical, immunofluorescence, immunoblot, and quantitative reverse-transcription polymerase chain reaction analyses (qRT-PCR) in liver specimens from NAFLD subjects, from a murine dietary NAFLD model, and in FFA-treated hepatic spheroids and hepatocytes. RESULTS: YAP-target gene expression correlated with increasing fibrosis stage in NAFLD patients and was associated with fibrosis in mice fed a NAFLD-inducing diet. Hepatocyte-specific YAP deletion in the murine NAFLD model attenuated diet-induced fibrosis, suggesting a causative role of YAP in NAFLD-related fibrosis. Likewise, in hepatic spheroids composed of Huh7 hepatoma cells and primary human hepatic stellate cells, Huh7 YAP silencing reduced FFA-induced fibrogenic gene expression. Notably, inhibition of p38 mitogen-activated protein kinase could block YAP activation in FFA-treated Huh7 cells. CONCLUSIONS: These studies provide further evidence for the pathological role of YAP in NAFLD-associated fibrosis and that YAP activation in NAFLD may be driven by FFA-induced p38 MAPK activation.

Pan-cancer Transcriptomic Predictors of Perineural Invasion Improve Occult Histopathologic Detection.

PURPOSE: Perineural invasion (PNI) is associated with aggressive tumor behavior, recurrence, and metastasis, and can influence the administration of adjuvant treatment. However, standard histopathologic examination has limited sensitivity in detecting PNI and does not provide insights into its mechanistic underpinnings. EXPERIMENTAL DESIGN: A multivariate Cox regression was performed to validate associations between PNI and survival in 2,029 patients across 12 cancer types. Differential expression and gene set enrichment analysis were used to learn PNI-associated programs. Machine learning models were applied to build a PNI gene expression classifier. A blinded re-review of hematoxylin and eosin (H&E) slides by a board-certified pathologist helped determine whether the classifier could improve occult histopathologic detection of PNI. RESULTS: PNI associated with both poor overall survival [HR, 1.73; 95% confidence interval (CI), 1.27-2.36; P < 0.001] and disease-free survival (HR, 1.79; 95% CI, 1.38-2.32; P < 0.001). Neural-like, prosurvival, and invasive programs were enriched in PNI-positive tumors (P adj < 0.001). Although PNI-associated features likely reflect in part the increased presence of nerves, many differentially expressed genes mapped specifically to malignant cells from single-cell atlases. A PNI gene expression classifier was derived using random forest and evaluated as a tool for occult histopathologic detection. On a blinded H&E re-review of sections initially described as PNI negative, more specimens were reannotated as PNI positive in the high classifier score cohort compared with the low-scoring cohort (P = 0.03, Fisher exact test). CONCLUSIONS: This study provides salient biological insights regarding PNI and demonstrates a role for gene expression classifiers to augment detection of histopathologic features.

Morphologic and molecular analysis of early-onset gastric cancer.

BACKGROUND: Evidence suggests that early-onset gastric cancers are distinct from traditional gastric cancers; however, detailed genomic and morphologic characterization of these cancers has not been performed. METHODS: Genomic analysis was performed for 81 patients with gastric cancer who were 50 years old or younger; pathology slides were available for 53 of these patients, and they were re-reviewed to perform a morphologic-molecular correlation analysis. The results were compared with corresponding cBioPortal data and The Cancer Genome Atlas (TCGA) analysis, which represent traditional gastric cancers. The TP53 molecular signature was established to determine the pattern of somatic mutational damage. Variants of potential germline origin were also identified from next-generation sequencing data. RESULTS: A higher rate of CDH1 mutations (22.2% of early-onset gastric cancers vs 11.4% of traditional gastric cancers; P = .0042) but a similar rate of TP53 mutations (63% of early-onset gastric cancers vs 56.6% of traditional gastric cancers; P = .2674) were seen in early-onset cancers in comparison with traditional gastric cancers. The diffuse/mixed types correlated with the TCGA genomically stable type, and the remaining Lauren types correlated with the TCGA chromosomal instability type. Diffuse and indeterminate histologic types (overall survival, 26.25 months for the intestinal type, 20.5 months for the mixed type, 12.62 months for the diffuse type, and 9 months for the indeterminate type; P = .027) and the presence of a CDH1 gene mutation (overall survival, 9 months for mutant CDH1 and 22 months for wild-type CDH1; P = .013) significantly correlated with worse survival. The TP53 gene frequently showed transition mutations (65.5%) involving the CpG sites (49%). Variants of potential germline origin were seen in high-penetrance genes (CDH1 and APC) and moderate-penetrance genes (ATM, NBN, and MUTYH) in 9.9% of cancers. CONCLUSIONS: Early-onset gastric cancer has distinct genomic alterations, such as CDH1 mutations, but shares with traditional gastric cancers a high frequency of TP53 mutations and the TP53 mutagenic signature. Diffuse and indeterminate histologic types and the presence of a CDH1 mutation are associated with worse overall survival. Endogenous factors leading to cytosine deamination and potential germline alterations in moderate-penetrance cancer susceptibility genes may be implicated in the pathogenesis of these cancers.