Intramucosal lipomas of the colon implicate Cowden syndrome.

Intramucosal lipomas are rare and easily overlooked by pathologists, despite their diagnostic significance for Cowden syndrome (PTEN hamartoma tumor syndrome), an inherited multiorgan cancer syndrome. Only 25-35% of patients harbor identifiable PTEN mutations, thus clinical features, like intramucosal lipomas, remain the mainstay of diagnosis. The significance and diagnostic approach to intramucosal lipomas have not been thoroughly addressed in the literature. Intramucosal lipomas are mimicked by pseudolipomatosis coli, an artifactual mucosal gas infiltration from endoscopic insufflation. This differential was investigated by morphology and S-100 immunohistochemistry. Twenty-five colonic intramucosal lipomas were identified from 176 archival gastrointestinal lipomas from 1998 to 2017. Controls included 40 submucosal lipomas and 30 pseudolipomatoses. S-100 immunohistochemistry on all 95 lesions confirmed delicate fat vacuole membranous and nuclear S-100 staining in lipomas absent from pseudolipomatoses. Differentiating morphology between intramucosal lipoma and pseudolipomatosis, respectively, included consistently large, regular fat vacuoles (92% vs 7%), associated spindle cells (80% vs 0%), and mucosal lymphoid aggregate involvement (12% vs 80%). Of the 25 intramucosal lipomas, five patients (20%) had confirmed Cowden syndrome (four with PTEN mutations). In four of these Cowden patients, the intramucosal lipoma was the index diagnostic lesion. Three (12%) intramucosal lipoma patients had additional clinical features associated with Cowden syndrome, but did not meet the diagnostic criteria. Sporadic-type intramucosal lipomas were identified in 17 patients (68%) without evidence of Cowden syndrome, including three with normal PTEN genetic testing. No distinguishing endoscopic or pathologic polyp features were identified between sporadic and syndromic intramucosal lipomas. These data provide evidence that intramucosal lipomas are important harbingers of Cowden syndrome, making up approximately one-third of this series, the largest in the literature. We also show for the first time that two-thirds of intramucosal lipomas are sporadic. Gastrointestinal pathologists, gastroenterologists, and geneticists should increase their awareness of this subtle but diagnosable lesion strongly associated with Cowden syndrome.

Needle size has only a limited effect on outcomes in EUS-guided fine needle aspiration: a systematic review and meta-analysis.

BACKGROUND: Several recent studies have investigated the utility of 19-, 22-, and 25-gauge needles in endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) of pancreatic and peri-pancreatic tumors. AIM: The objective of this study was to summarize data from these studies and estimate the effect of needle size on reported outcomes such as accuracy, adequacy, and complications. METHODS: Systematic review and meta-analysis comparing the effect of needle size (19, 22, and 25G) on diagnostic accuracy, adequacy, number of needle passes, and complications. RESULTS: 25G appear to confer an advantage in adequacy rates relative to 22G needles (risk difference = 0.12 %, 95 % CI 0.01, 0.25). There was no significant difference in accuracy with an overall sensitivity and specificity for 22G being 0.78 (95 % CI 0.74-0.81) and 1.00 (95 % CI 0.98-1.00) and an overall sensitivity and specificity for 25G being 0.91 (95 % CI 0.87-0.94) and 1.00 (95 % CI 0.97-1.00). There was no difference in number of passes or complications between 25 and 22G. The limited data available regarding 19G needles do not show evidence of improved outcomes with these devices. CONCLUSIONS: In the evaluation of pancreatic and peri-pancreatic lesions by EUS-FNA, 25G needles may confer an advantage in adequacy relative to 22G needles but confer no advantages with respect to accuracy, number of passes, or complications.

Distinguishing Gastrointestinal Leiomyomas From Muscularis Propria in Biopsy Specimens by Differential Expression of S100 Immunohistochemical Stain.

OBJECTIVES: Interpreting small biopsy specimens or fine-needle aspirations of gastrointestinal tract (GI) smooth muscle lesions may be challenging when the differential diagnosis includes leiomyoma vs muscularis propria (MP). We evaluated the utility of S100 staining in distinguishing GI leiomyomas from MP. METHODS: A search was conducted in our laboratory information system for cases of leiomyomas arising within the GI tract (2004-2021). Site-matched controls containing MP were selected (2018-2020). Five high-power fields (hpf) were counted on S100 immunohistochemical stains by two pathologists in the resections and by three different blinded pathologists in the biopsy specimens and analyzed. RESULTS: The median S100 count was 2.5/5 hpf in leiomyoma resection cases (n = 38), which was significantly lower than the median count of 548/5 hpf in MP (n = 19) with a P value of <.0001. The median S100 count in biopsy specimens (n = 16) was 1.2/5 hpf and within the expected range of 1 to 104/5 hpf (minimum-maximum value) established by the leiomyoma resections. S100 counts in the normal MP were significantly higher than those observed in leiomyomas (P < .001). CONCLUSIONS: S100 staining can aid in distinguishing a leiomyoma from MP in the GI tract, which is especially helpful when evaluating cases with limited sampling.

Multianalyte Serum Biomarker Panel for Early Detection of Pancreatic Adenocarcinoma.

PURPOSE: We determined whether a large, multianalyte panel of circulating biomarkers can improve detection of early-stage pancreatic ductal adenocarcinoma (PDAC). MATERIALS AND METHODS: We defined a biologically relevant subspace of blood analytes on the basis of previous identification in premalignant lesions or early-stage PDAC and evaluated each in pilot studies. The 31 analytes that met minimum diagnostic accuracy were measured in serum of 837 subjects (461 healthy, 194 benign pancreatic disease, and 182 early-stage PDAC). We used machine learning to develop classification algorithms using the relationship between subjects on the basis of their changes across the predictors. Model performance was subsequently evaluated in an independent validation data set from 186 additional subjects. RESULTS: A classification model was trained on 669 subjects (358 healthy, 159 benign, and 152 early-stage PDAC). Model evaluation on a hold-out test set of 168 subjects (103 healthy, 35 benign, and 30 early-stage PDAC) yielded an area under the receiver operating characteristic curve (AUC) of 0.920 for classification of PDAC from non-PDAC (benign and healthy controls) and an AUC of 0.944 for PDAC versus healthy controls. The algorithm was then validated in 146 subsequent cases presenting with pancreatic disease (73 benign pancreatic disease and 73 early- and late-stage PDAC cases) and 40 healthy control subjects. The validation set yielded an AUC of 0.919 for classification of PDAC from non-PDAC and an AUC of 0.925 for PDAC versus healthy controls. CONCLUSION: Individually weak serum biomarkers can be combined into a strong classification algorithm to develop a blood test to identify patients who may benefit from further testing.

Integrated Molecular Characterization of Intraductal Papillary Mucinous Neoplasms: An NCI Cancer Moonshot Precancer Atlas Pilot Project.

Intraductal papillary mucinous neoplasms (IPMN) are cystic precursor lesions to pancreatic ductal adenocarcinoma (PDAC). IPMNs undergo multistep progression from low-grade (LG) to high-grade (HG) dysplasia, culminating in invasive neoplasia. While patterns of IPMN progression have been analyzed using multiregion sequencing for somatic mutations, there is no integrated assessment of molecular events, including copy-number alterations (CNA) and transcriptional changes that accompany IPMN progression. We performed laser capture microdissection on surgically resected IPMNs of varying grades of histologic dysplasia obtained from 23 patients, followed by whole-exome and whole-transcriptome sequencing. Overall, HG IPMNs displayed a significantly greater aneuploidy score than LG lesions, with chromosome 1q amplification being associated with HG progression and with cases that harbored co-occurring PDAC. Furthermore, the combined assessment of single-nucleotide variants (SNV) and CNAs identified both linear and branched evolutionary trajectories, underscoring the heterogeneity in the progression of LG lesions to HG and PDAC. At the transcriptome level, upregulation of MYC-regulated targets and downregulation of transcripts associated with the MHC class I antigen presentation machinery as well as pathways related to glycosylation were a common feature of progression to HG. In addition, the established PDAC transcriptional subtypes (basal-like and classical) were readily apparent within IPMNs. Taken together, this work emphasizes the role of 1q copy-number amplification as a putative biomarker of high-risk IPMNs, underscores the importance of immune evasion even in noninvasive precursor lesions, and reinforces that evolutionary pathways in IPMNs are heterogenous, comprised of both SNV and CNA-driven events. SIGNIFICANCE: Integrated molecular analysis of genomic and transcriptomic alterations in the multistep progression of IPMNs, which are bona fide precursors of pancreatic cancer, identifies features associated with progression of low-risk lesions to high-risk lesions and cancer, which might enable patient stratification and cancer interception strategies.

Differential methylation of G-protein coupled receptor signaling genes in gastrointestinal neuroendocrine tumors.

Neuroendocrine tumors (NETs) of the small intestine undergo large chromosomal and methylation changes. The objective of this study was to identify methylation differences in NETs and consider how the differentially methylated genes may impact patient survival. Genome-wide methylation and chromosomal copy number variation (CNV) of NETs from the small intestine and appendix were measured. Tumors were divided into three molecular subtypes according to CNV results: chromosome 18 loss (18LOH), Multiple CNV, and No CNV. Comparison of 18LOH tumors with MultiCNV and NoCNV tumors identified 901 differentially methylated genes. Genes from the G-protein coupled receptor (GPCR) pathways are statistically overrepresented in the differentially methylated genes. One of the highlighted genes from the GPCR pathway is somatostatin (SST), a clinical target for NETs. Patient survival based on low versus high methylation in all samples identified four significant genes (p < 0.05) OR2S2, SMILR, RNU6-653P, and AC010543.1. Within the 18LOH molecular subtype tumors, survival differences were identified in high versus low methylation of 24 genes. The most significant is TRHR (p < 0.01), a GPCR with multiple FDA-approved drugs. By separating NETs into different molecular subtypes based on chromosomal changes, we find that multiple GPCRs and their ligands appear to be regulated through methylation and correlated with survival. These results suggest opportunities for better treatment strategies for NETs based on molecular features.

Detection of circulating tumor DNA without a tumor-informed search using next-generation sequencing is a prognostic biomarker in pancreatic ductal adenocarcinoma.

The confounding effects of next-generation sequencing (NGS) noise on detection of low frequency circulating tumor DNA (ctDNA) without a priori knowledge of solid tumor mutations has limited the applications of circulating cell-free DNA (ccfDNA) in clinical oncology. Here, we use a 118 gene panel and leverage ccfDNA technical replicates to eliminate NGS-associated errors while also enhancing detection of ctDNA from pancreatic ductal adenocarcinomas (PDACs). Pre-operative ccfDNA and tumor DNA were acquired from 14 patients with PDAC (78.6% stage II-III). Post-operative ccfDNA was also collected from 11 of the patients within 100 days of surgery. ctDNA detection was restricted to variants corresponding to pathogenic mutations in PDAC present in both replicates. PDAC-associated pathogenic mutations were detected in pre-operative ccfDNA in four genes (KRAS, TP53, SMAD4, ALK) from five patients. Of the nine ctDNA variants detected (variant allele frequency: 0.08%-1.59%), five had a corresponding mutation in tumor DNA. Pre-operative detection of ctDNA was associated with shorter survival (312 vs. 826 days; χ2=5.4, P = 0.021). Guiding ctDNA detection in pre-operative ccfDNA based on mutations present in tumor DNA yielded a similar survival analysis. Detection of ctDNA in the post-operative ccfDNA with or without tumor-informed guidance was not associated with outcomes. Therefore, the detection of PDAC-derived ctDNA during a broad and untargeted survey of ccfDNA with NGS may be a valuable, non-invasive, prognostic biomarker to integrate into the clinical assessment and management of patients prior to surgery.

Protective autophagy elicited by RAF→MEK→ERK inhibition suggests a treatment strategy for RAS-driven cancers.

Pancreatic ductal adenocarcinoma (PDA) was responsible for ~ 44,000 deaths in the United States in 2018 and is the epitome of a recalcitrant cancer driven by a pharmacologically intractable oncoprotein, KRAS1-4. Downstream of KRAS, the RAF→MEK→ERK signaling pathway plays a central role in pancreatic carcinogenesis5. However, paradoxically, inhibition of this pathway has provided no clinical benefit to patients with PDA6. Here we show that inhibition of KRAS→RAF→MEK→ERK signaling elicits autophagy, a process of cellular recycling that protects PDA cells from the cytotoxic effects of KRAS pathway inhibition. Mechanistically, inhibition of MEK1/2 leads to activation of the LKB1→AMPK→ULK1 signaling axis, a key regulator of autophagy. Furthermore, combined inhibition of MEK1/2 plus autophagy displays synergistic anti-proliferative effects against PDA cell lines in vitro and promotes regression of xenografted patient-derived PDA tumors in mice. The observed effect of combination trametinib plus chloroquine was not restricted to PDA as other tumors, including patient-derived xenografts (PDX) of NRAS-mutated melanoma and BRAF-mutated colorectal cancer displayed similar responses. Finally, treatment of a patient with PDA with the combination of trametinib plus hydroxychloroquine resulted in a partial, but nonetheless striking disease response. These data suggest that this combination therapy may represent a novel strategy to target RAS-driven cancers.

Publisher Correction: Protective autophagy elicited by RAF→MEK→ERK inhibition suggests a treatment strategy for RAS-driven cancers.

In the version of this article initially published, the label over the bottom schematic in Fig. 1a was "pH > 5.0"; it should have been "pH < 5.0". Further, the original article misspelt the surname of Katrin P. Guillen as "Gullien". These errors have been corrected in the print, PDF and HTML versions of the article.

PD-L1 protein expression in tumour cells and immune cells in mismatch repair protein-deficient and -proficient colorectal cancer: the foundation study using the SP142 antibody and whole section immunohistochemistry.

AIMS: Routine application of PD-L1 immunohistochemistry (IHC) in colorectal cancer (CRC) is limited due to lack of standardized scoring criteria, antibody clones, and intratumoral staining heterogeneity. We assessed PD-L1 protein expression on full face CRC tissue sections and applied two algorithms based on the published clinical trials that support the recent FDA approval for immune checkpoint inhibitors (ICPI) therapy in non-small cell lung cancer (NSCLC). METHODS: PD-L1/CD274 IHC (Roche/Ventana, clone SP142) was performed on representative tumour blocks from 52 mismatch repair-deficient (MMR-D) and 52 MMR-proficient (MMR-P) CRCs. Membranous PD-L1 expression was scored for the tumour cell (TC) and tumour-infiltrating immune cell (IC) components. PD-L1 positivity status was determined based on the published NSCLC clinical trials that utilized the Ventana SP142 assay. Hybrid capture-based comprehensive genomic profiling (CGP) was performed on a separate set of 2268 clinically advanced CRCs and the frequency of PD-L1/PD-L2 amplification was determined. RESULTS: PD-L1 expression in the TC and IC correlated with MMR-D (p=0.013, p<0.0001), T stage (p=0.036, p=0.0036) and clinical stage (p=0.022, p=0.0037). PD-L1 positivity status correlated with MMR-D by two algorithms. Five of 2268 (<1%) advansced CRCs demonstrated amplification of either the PD-L1 or PD-L2 genes by CGP. CONCLUSIONS: PD-L1 expression in TC and IC is associated with advanced stage and MMR-D. PD-L1 positivity status by the published algorithm is associated with MMR-D. PD-L1 amplification is extremely uncommon in CRC. Evaluation of whole tissue section and incorporation of IC staining enhance the sensitivity to screen patients who may benefit from ICPI therapy.

Chemoprevention with Cyclooxygenase and Epidermal Growth Factor Receptor Inhibitors in Familial Adenomatous Polyposis Patients: mRNA Signatures of Duodenal Neoplasia.

To identify gene expression biomarkers and pathways targeted by sulindac and erlotinib given in a chemoprevention trial with a significant decrease in duodenal polyp burden at 6 months (P < 0.001) in familial adenomatous polyposis (FAP) patients, we biopsied normal and polyp duodenal tissues from patients on drug versus placebo and analyzed the RNA expression. RNA sequencing was performed on biopsies from the duodenum of FAP patients obtained at baseline and 6-month endpoint endoscopy. Ten FAP patients on placebo and 10 on sulindac and erlotinib were selected for analysis. Purity of biopsied polyp tissue was calculated from RNA expression data. RNAs differentially expressed between endpoint polyp and paired baseline normal were determined for each group and mapped to biological pathways. Key genes in candidate pathways were further validated by quantitative RT-PCR. RNA expression analyses of endpoint polyp compared with paired baseline normal for patients on placebo and drug show that pathways activated in polyp growth and proliferation are blocked by this drug combination. Directly comparing polyp gene expression between patients on drug and placebo also identified innate immune response genes (IL12 and IFNγ) preferentially expressed in patients on drug. Gene expression analyses from tissue obtained at endpoint of the trial demonstrated inhibition of the cancer pathways COX2/PGE2, EGFR, and WNT. These findings provide molecular evidence that the drug combination of sulindac and erlotinib reached the intended tissue and was on target for the predicted pathways. Furthermore, activation of innate immune pathways from patients on drug may have contributed to polyp regression. Cancer Prev Res; 11(1); 4-15. ©2017 AACRSee related editorial by Shureiqi, p. 1.

Environmental Enrichment Induces Pericyte and IgA-Dependent Wound Repair and Lifespan Extension in a Colon Tumor Model.

Environmental enrichment (EE) replicates mind-body therapy by providing complex housing to laboratory animals to improve their activity levels, behavior, and social interactions. Using a Tcf4Het/+ApcMin/+-mediated model of colon tumorigenesis, we found that EE vastly improved the survival of tumor-bearing animals, with differential effect on tumor load in male compared to female animals. Analysis of Tcf4Het/+ApcMin/+ males showed drastically reduced expression of circulating inflammatory cytokines and induced nuclear hormone receptor (NHR) signaling, both of which are common in the wound repair process. Interestingly, EE provoked tumor wound repair resolution through revascularization, plasma cell recruitment and IgA secretion, replacement of glandular tumor structures with pericytes in a process reminiscent of scarring, and normalization of microbiota. These EE-dependent changes likely underlie the profound improvement in survival of colon-tumor-bearing Tcf4Het/+ApcMin/+ males. Our studies highlight the exciting promise of EE in the design of future therapeutic strategies for colon cancer patients.

Methods specification for diagnostic test accuracy studies in fine-needle aspiration cytology: a survey of reporting practice.

Diagnostic test accuracy (DTA) studies on fine-needle aspiration cytology (FNAC) often show considerable variability in diagnostic accuracy between study centers. Many factors affect the accuracy of FNAC. A complete description of the testing parameters would help make valid comparisons between studies and determine causes of performance variation. We investigated the manner in which test conditions are specified in FNAC DTA studies to determine which parameters are most commonly specified and the frequency with which they are specified and to see whether there is significant variability in reporting practice. We identified 17 frequently reported test parameters and found significant variation in the reporting of these test specifications across studies. On average, studies reported 5 of the 17 items that would be required to specify the test conditions completely. A more complete and standardized reporting of methods, perhaps by means of a checklist, would improve the interpretation of FNAC DTA studies.