Tacrolimus's Time Below Therapeutic Range Is Associated With Acute Pancreatic Graft Rejection and the Development of De Novo Donor-specific Antibodies

Tacrolimus is pivotal in pancreas transplants but poses challenges in maintaining optimal levels due to recipient differences. This study aimed to explore the utility of time spent below the therapeutic range and intrapatient variability in predicting rejection and de novo donor-specific antibody (dnDSA) development in pancreas graft recipients. This retrospective unicentric study included adult pancreas transplant recipients between January 2006 and July 2020. Recorded variables included demographics, immunosuppression details, HLA matching, biopsy results, dnDSA development, and clinical parameters. Statistical analysis included ROC curves, sensitivity, specificity, and predictive values. A total of 131 patients were included. Those with biopsy-proven acute rejection (BPAR, 12.2%) had more time (39.9% ± 24% vs. 25.72% ± 21.57%, p = 0.016) and tests (41.95% ± 13.57% vs. 29.96% ± 17.33%, p = 0.009) below therapeutic range. Specific cutoffs of 31.5% for time and 34% for tests below the therapeutic range showed a high negative predictive value for BPAR (93.98% and 93.1%, respectively). Similarly, patients with more than 34% of tests below the therapeutic range were associated with dnDSA appearance (38.9% vs. 9.4%, p = 0.012; OR 6.135, 1.346-27.78). In pancreas transplantation, maintaining optimal tacrolimus levels is crucial. Suboptimal test percentages below the therapeutic range prove valuable in identifying acute graft rejection risk.

Linked-color imaging versus high definition white-light endoscopy for evaluation of post-polypectomy scars of nonpedunculated lesions: LCI-Scar study

BACKGROUND

Detection and treatment of recurrence after piecemeal endoscopic mucosal resection of nonpedunculated colorectal polyps are crucial for avoidance of post-colonoscopy cancer. Linked-color imaging (LCI) has demonstrated improved polyp detection but has never been assessed for evaluation of post-polypectomy scars. Our aim was to compare sensitivity and negative predictive value (NPV) between LCI and white-light endoscopy (WLE) for detection of post-polypectomy recurrence.

METHODS

Patients undergoing surveillance colonoscopy after resection of lesions ≥15 mm were included in this prospective, single-center, randomized, crossover study. Each post-polypectomy scar underwent two examinations, one with LCI and the other with WLE, performed by two blinded endoscopists. Blue-light imaging (BLI) was then applied. A diagnosis of recurrence with a level of confidence was made for each modality and histopathology was the gold standard.

RESULTS

129 patients with 173 scars were included. Baseline patient, lesion, and procedural characteristics were similar in both arms. Recurrence was detected in 56/173 (32.4%), with 27/56 (48.2%) adenomas and 29/56 (51.8%) serrated lesions. LCI had greater sensitivity (96.4% [95%CI 87.8%-99.5%]) versus WLE (89.3% [95%CI 78.1%-95.9%]) and greater NPV (98.1% [95%CI 93.4%-99.8%] versus 94.6% [95%CI 88.7%-98.0%]). Paired concordance between modalities was 96.0%. In discordant cases, LCI identified four true-positive cases not detected by WLE and reclassified one false-positive of WLE. WLE reclassified two false positives of LCI without any increase in recurrence detection.

CONCLUSIONS

LCI was highly accurate and had greater ability than WLE to rule out recurrence on post-polypectomy scars after resection of large polyps.

Flanagan's condensed protocol for neurodegenerative diseases. Implementation in a clinical autopsy setting with partial supervision of a neuropathologist

The Condensed Protocol (CP) was originally developed for the evaluation of Alzheimer's Disease (AD) and other neurodegenerative diseases as a workable alternative to the complex and costly established autopsy guidelines. The study objective is to examine the degree of implementation of the CP in the pathology department of a third level university hospital in a period of 5 years. Clinical autopsies performed between 2016 and 2021 on patients aged 65 years or over and did not require a specific neuropathological examination were reviewed. Histological screening and staging of neurodegenerative diseases was performed using the original immunohistochemical stains. Out of 255 autopsies, 204 met the inclusion criteria and 190 could be reviewed. The CP was applied to 99 cases; histological signs of neurodegenerative disease were observed in 92. Sampling errors were detected in 59 cases. Immunohistochemical studies were performed in 68 cases. The diseases identified were: 31 cases of AD (12 low grade; 19 intermediate), 18 amyloid angiopathy, 15 primary age-related tauopathy, 6 argyrophilic grain disease, 3 progressive supranuclear palsy, 1 Lewy body disease (of 22 cases), and 2 limbic-predominant age TDP43 encephalopathy (of 5 cases). In 30 out of 83 cases, there was more severe vascular pathology in complete sections of frontal cortex and lentiform nucleus. The CP allows reliable detection and staging of AD and related neurodegenerative diseases in clinical autopsies. However, supervision by a neuropathologist seems necessary for a fully successful implementation of the CP in a clinical hospital setting.

Loss of the epithelial marker CDX1 predicts poor prognosis in early-stage CRC patients

BACKGROUND

We have previously shown that non-curative chemotherapy imposes fetal conversion and high metastatic capacity to cancer cells. From the set of genes differentially expressed in Chemotherapy Resistant Cells, we obtained a characteristic fetal intestinal cell signature that is present in a group of untreated tumors and is sufficient to predict patient prognosis. A feature of this fetal signature is the loss of CDX1.

METHODS

We have analyzed transcriptomic data in public datasets and performed immunohistochemistry analysis of paraffin embedded tumor samples from two cohorts of colorectal cancer patients.

RESULTS

We demonstrated that low levels of CDX1 are sufficient to identify patients with poorest outcome at the early tumor stages II and III. Presence tumor areas that are negative for CDX1 staining in stage I cancers is associated with tumor relapse.

CONCLUSIONS

Our results reveal the actual possibility of incorporating CDX1 immunostaining as a valuable biomarker for CRC patients.

Banff 2022 pancreas transplantation multidisciplinary report: Refinement of guidelines for T cell-mediated rejection, antibody-mediated rejection and islet pathology. Assessment of duodenal cuff biopsies and noninvasive diagnostic methods

The Banff pancreas working schema for diagnosis and grading of rejection is widely used for treatment guidance and risk stratification in centers that perform pancreas allograft biopsies. Since the last update, various studies have provided additional insight regarding the application of the schema and enhanced our understanding of additional clinicopathologic entities. This update aims to clarify terminology and lesion description for T cell-mediated and antibody-mediated allograft rejections, in both active and chronic forms. In addition, morphologic and immunohistochemical tools are described to help distinguish rejection from nonrejection pathologies. For the first time, a clinicopathologic approach to islet pathology in the early and late posttransplant periods is discussed. This update also includes a discussion and recommendations on the utilization of endoscopic duodenal donor cuff biopsies as surrogates for pancreas biopsies in various clinical settings. Finally, an analysis and recommendations on the use of donor-derived cell-free DNA for monitoring pancreas graft recipients are provided. This multidisciplinary effort assesses the current role of pancreas allograft biopsies and offers practical guidelines that can be helpful to pancreas transplant practitioners as well as experienced pathologists and pathologists in training.

Lymph Node Molecular Analysis with OSNA Enables the Identification of pT1 CRC Patients at Risk of Recurrence: A Multicentre Study

Early-stage colorectal carcinoma (CRC)-pT1-is a therapeutic challenge and presents some histological features related to lymph node metastasis (LNM). A significant proportion of pT1 CRCs are treated surgically, resulting in a non-negligible surgical-associated mortality rate of 1.5-2%. Among these cases, approximately 6-16% exhibit LNM, but the impact on survival is unclear. Therefore, there is an unmet need to establish an objective and reliable lymph node (LN) staging method to optimise the therapeutic management of pT1 CRC patients and to avoid overtreating or undertreating them. In this multicentre study, 89 patients with pT1 CRC were included. All histological features associated with LNM were evaluated. LNs were assessed using two methods, One-Step Nucleic Acid Amplification (OSNA) and the conventional FFPE plus haematoxylin and eosin (H&E) staining. OSNA is an RT-PCR-based method for amplifying CK19 mRNA. Our aim was to assess the performance of OSNA and H&E in evaluating LNs to identify patients at risk of recurrence and to optimise their clinical management. We observed an 80.9% concordance in LN assessment using the two methods. In 9% of cases, LNs were found to be positive using H&E, and in 24.7% of cases, LNs were found to be positive using OSNA. The OSNA results are provided as the total tumour load (TTL), defined as the total tumour burden present in all the LNs of a surgical specimen. In CRC, a TTL ≥ 6000 CK19 m-RNA copies/µL is associated with poor prognosis. Three patients had TTL > 6000 copies/μL, which was associated with higher tumour budding. The discrepancies observed between the OSNA and H&E results were mostly attributed to tumour allocation bias. We concluded that LN assessment with OSNA enables the identification of pT1 CRC patients at some risk of recurrence and helps to optimise their clinical management.

The EMT factor ZEB1 paradoxically inhibits EMT in BRAF-mutant carcinomas

Despite being in the same pathway, mutations of KRAS and BRAF in colorectal carcinomas (CRCs) determine distinct progression courses. ZEB1 induces an epithelial-to-mesenchymal transition (EMT) and is associated with worse progression in most carcinomas. Using samples from patients with CRC, mouse models of KrasG12D and BrafV600E CRC, and a Zeb1-deficient mouse, we show that ZEB1 had opposite functions in KRAS- and BRAF-mutant CRCs. In KrasG12D CRCs, ZEB1 was correlated with a worse prognosis and a higher number of larger and undifferentiated (mesenchymal or EMT-like) tumors. Surprisingly, in BrafV600E CRC, ZEB1 was associated with better prognosis; fewer, smaller, and more differentiated (reduced EMT) primary tumors; and fewer metastases. ZEB1 was positively correlated in KRAS-mutant CRC cells and negatively in BRAF-mutant CRC cells with gene signatures for EMT, cell proliferation and survival, and ERK signaling. On a mechanistic level, ZEB1 knockdown in KRAS-mutant CRC cells increased apoptosis and reduced clonogenicity and anchorage-independent growth; the reverse occurred in BRAFV600E CRC cells. ZEB1 is associated with better prognosis and reduced EMT signature in patients harboring BRAF CRCs. These data suggest that ZEB1 can function as a tumor suppressor in BRAF-mutant CRCs, highlighting the importance of considering the KRAS/BRAF mutational background of CRCs in therapeutic strategies targeting ZEB1/EMT.

Preclinical Evaluation of a Microwave-Based Accessory Device for Colonoscopy in an In Vivo Porcine Model with Colorectal Polyps

BACKGROUND AND AIMS

Colonoscopy is currently the most effective way of detecting colorectal cancer and removing polyps, but it has some drawbacks and can miss up to 22% of polyps. Microwave imaging has the potential to provide a 360° view of the colon and addresses some of the limitations of conventional colonoscopy. This study evaluates the feasibility of a microwave-based colonoscopy in an in vivo porcine model.

METHODS

A prototype device with microwave antennas attached to a conventional endoscope was tested on four healthy pigs and three gene-targeted pigs with mutations in the adenomatous polyposis coli gene. The first four animals were used to evaluate safety and maneuverability and compatibility with endoscopic tools. The ability to detect polyps was tested in a series of three gene-targeted pigs.

RESULTS

the microwave-based device did not affect endoscopic vision or cause any adverse events such as deep mural injuries. The microwave system was stable during the procedures, and the detection algorithm showed a maximum detection signal for adenomas compared with healthy mucosa.

CONCLUSIONS

Microwave-based colonoscopy is feasible and safe in a preclinical model, and it has the potential to improve polyp detection. Further investigations are required to assess the device's efficacy in humans.

Germline mutations in WNK2 could be associated with serrated polyposis syndrome

BACKGROUND

Patients with serrated polyposis syndrome (SPS) have multiple and/or large serrated colonic polyps and higher risk for colorectal cancer. SPS inherited genetic basis is mostly unknown. We aimed to identify new germline predisposition factors for SPS by functionally evaluating a candidate gene and replicating it in additional SPS cohorts.

METHODS

After a previous whole-exome sequencing in 39 SPS patients from 16 families (discovery cohort), we sequenced specific genes in an independent validation cohort of 211 unrelated SPS cases. Additional external replication was also available in 297 SPS cases. The WNK2 gene was disrupted in HT-29 cells by gene editing, and WNK2 variants were transfected using a lentiviral delivery system. Cells were analysed by immunoblots, real-time PCR and functional assays monitoring the mitogen-activated protein kinase (MAPK) pathway, cell cycle progression, survival and adhesion.

RESULTS

We identified 2 rare germline variants in the WNK2 gene in the discovery cohort, 3 additional variants in the validation cohort and 10 other variants in the external cohorts. Variants c.2105C>T (p.Pro702Leu), c.4820C>T (p.Ala1607Val) and c.6157G>A (p.Val2053Ile) were functionally characterised, displaying higher levels of phospho-PAK1/2, phospho-ERK1/2, CCND1, clonogenic capacity and MMP2.

CONCLUSION

After whole-exome sequencing in SPS cases with familial aggregation and replication of results in additional cohorts, we identified rare germline variants in the WNK2 gene. Functional studies suggested germline WNK2 variants affect protein function in the context of the MAPK pathway, a molecular hallmark in this disease.

Targeted transcriptomic analysis of pancreatic adenocarcinoma in EUS-FNA samples by NanoString technology

Background: Integration of transcriptomic testing into EUS-FNA samples is a growing need for precision oncology in pancreatic ductal adenocarcinoma (PDAC). The NanoString platform is suitable for transcriptome profiling in low yield RNA samples. Methods: Inclusion of patients that underwent EUS-FNA cytological diagnosis of pancreatic ductal adenocarcinoma using 19G and/or 22G needles and subsequent surgical resection. Formalin-fixed, paraffin-embedded (FFPE) cytological and surgical samples underwent RNA extraction and transcriptomic analysis using a custom 52-gene NanoString panel of stromal PDAC features. Cell type abundance was quantified in FFPE specimens and correlated. Results: 18 PDAC patients were included. Mean EUS-FNA passes was 2 + 0.7. All FFPE passed the RNA quality control for genomic analysis. Hierarchical clustering on the global gene expression data showed that genes were differentially expressed between EUS and surgical samples. A more enriched cancer-associated fibroblasts and epithelial-mesenchymal transition transcriptomic profile was observed across surgical specimens whereas immunological biomarkers were more represented in EUS-FNA samples. Cytological examination confirmed a scanty representation of CAF and more immunological cell abundance in cytological samples in comparison to surgical specimens. Conclusion: Targeted transcriptomic NanoString profiling of PDAC samples obtained by EUS-FNA is a feasible approach for pre-surgical molecular analysis although stromal CAF/EMT mRNA biomarkers are underrepresented.

Abstract 314: Intratumor genetic heterogeneity dictates metastatic subclones in stage II colon cancer

The high incidence of colon cancer (CC) worldwide is a major health concern. Although surgery and adjuvant chemotherapy are effective to a high extent in lymph-node negative colon cancers, there are still some 10-15% of patients that show disease relapse within the next 5-year period after intended curative surgery. We hypothesize that genomic instability and intratumor heterogeneity fuel the formation of subclonal populations in the primary tumor that might promote metastasis. In the current study, we assessed the presence of intratumor heterogeneity in CC using multiplex interphase FISH (miFISH) and whole-exome sequencing (WES) to evaluate samples obtained from primary stage II colon tumors and their patient-matched associated liver metastases using multi-region sampling (N=9). In combination with genome-wide copy-number changes obtained from WES analysis, miFISH allowed the simultaneous quantification of copy-numbers for nine CC relevant genes and a centromeric ploidy control probe in intact tumor nuclei derived from archival patient material. Our preliminary data on the four cases analyzed so far, revealed high similarities regarding copy-number changes and ploidy between primary tumor and metastatic samples for three of the cases. While two of these cases showed either triploid or highly aneuploid genomes with different degrees of genomic instability and subclonality among them, the third case displayed a diploid content for both matched lesions. Intriguingly, as seen by miFISH and WES, loss of CDX2 in the primary tumor might have originated the main clonal population giving rise to metastasis in this latter case. Conversely, the fourth case analyzed exhibited a triploid baseline for the primary tumor while the metastasis revealed a diploid population. Interestingly, despite higher absolute copy numbers in the primary tumor, there was an overlap of five of the gains and losses observed for the major clone populations of the tumor and metastasis by miFISH. However, two of the highly clonal gains observed in the tumor, namely the EGFR and MYC gain, were not present in the metastasis. Altogether, in addition to the ploidy change, results indicated major discrete copy-number changes from primary tumor to metastasis in this patient. In summary, we show here that the combined analysis of WES and miFISH is able to describe the subclonal composition of copy-number alterations in primary tumors and their patientmatched liver metastases. Future perspectives also include the assessment of subclonality affecting single-nucleotide variants to complete the genomic landscape of tumor evolution and clonal development in this patient cohort with the goal to better understand the nature of these early metastases.

Citation Format: Sanam Yaghoubi, Kerstin Heselmeyer-Haddad, Ivan Archilla, Carolina Parra, Darawalee Wangsa, Giancarlo Castellano, Sara Lahoz, Veronica Pablo-Fontecha, Daniela Hirsch, Wei-Dong Chen, Thomas Ried, Miriam Cuatrecasas, Paul S. Meltzer, Jordi Camps. Intratumor genetic heterogeneity dictates metastatic subclones in stage II colon cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 314.

A Phase I-II multicenter trial with Avelumab plus autologous dendritic cell vaccine in pre-treated mismatch repair-proficient (MSS) metastatic colorectal cancer patients; GEMCAD 1602 study

BACKGROUND

Immune check-point blockade (ICB) has shown clinical benefit in mismatch repair-deficient/microsatellite instability high metastatic colorectal cancer (mCRC) but not in mismatch repair-proficient/microsatellite stable patients. Cancer vaccines with autologous dendritic cells (ADC) could be a complementary therapeutic approach to ICB as this combination has the potential to achieve synergistic effects.

METHODS

This was a Phase I/II multicentric study with translational sub-studies, to evaluate the safety, pharmacodynamics and anti-tumor effects of Avelumab plus ADC vaccine in heavily pre-treated MSS mCRC patients. Primary objective was to determine the maximum tolerated dose and the efficacy of the combination. The primary end-point was 40% progression-free survival at 6 months with a 2 Simon Stage.

RESULTS

A total of 28 patients were screened and 19 pts were included. Combined therapy was safe and well tolerated. An interim analysis (Simon design first-stage) recommended early termination because only 2/19 (11%) patients were disease free at 6 months. Median PFS was 3.1 months [2.1-5.3 months] and overall survival was 12.2 months [3.2-23.2 months]. Stimulation of immune system was observed in vitro but not clinically. The evaluation of basal RNA-seq noted significant changes between pre and post-therapy liver biopsies related to lipid metabolism and transport, inflammation and oxidative stress pathways.

CONCLUSIONS

The combination of Avelumab plus ADC vaccine is safe and well tolerated but exhibited modest clinical activity. Our study describes, for the first-time, a de novo post-therapy metabolic rewiring, that could represent novel immunotherapy-induced tumor vulnerabilities.

Tumour Cell Seeding to Lymph Nodes from In Situ Colorectal Cancer

Lymph node (LN) metastasis is an important prognostic factor in colorectal cancer (CRC). We aimed to demonstrate the presence of lymphatic vessels (LV) in the mucosa of in-situ (pTis) CRC, and of detectable tumour burden in regional LNs. This is an observational retrospective study of 39 surgically resected in situ CRCs. The number of LVs was evaluated in both pTis and normal mucosa using D2-40 immunostains. All LNs were assessed with both H&E and the One Step Nucleic Acid Amplification (OSNA) assay, and the results were correlated with clinicopathological features. D2-40 immunohistochemisty revealed LVs in the lamina propria of all pTis CRC (100%), being absent in normal mucosa. A median of 16 LNs were freshly dissected per patient, and all cases were pN0 with H&E. Molecular LN analysis with OSNA revealed the presence of low amounts of tumour burden in 11/39 (28%) cases (range 400 to 4270 CK19 mRNA copies/µL), which had no clinical consequences. This study demonstrates the presence of LVs in the lamina propria in 100% of pTis CRC, as well as the presence of low amounts of tumour burden in regional LNs, only detected by molecular methods. Given the prognostic value of LN tumour burden, its molecular quantification may help a patient's clinical management.

Unraveling the impact of a germline heterozygous POLD1 frameshift variant in serrated polyposis syndrome

Serrated polyposis syndrome (SPS) is one of the most frequent polyposis syndromes characterized by an increased risk for developing colorectal cancer (CRC). Although SPS etiology has been mainly associated with environmental factors, germline predisposition to SPS could also be relevant for cases with familial aggregation or a family history of SPS/CRC. After whole-exome sequencing of 39 SPS patients from 16 families, we identified a heterozygous germline frameshift variant in the POLD1 gene (c.1941delG, p.(Lys648fs*46)) in a patient with SPS and CRC. Tumor presented an ultra-hypermutated phenotype and microsatellite instability. The POLD1 germline variant segregated in three additional SPS-affected family members. We attempted to create yeast and cellular models for this variant but were no viable. Alternatively, we generated patient-derived organoids (PDOs) from healthy rectal tissue of the index case, as well as from a control donor. Then, we challenged PDOs with a DNA-damaging agent to induce replication stress. No significant differences were observed in the DNA damage response between control and POLD1-Lys648fs PDOs, nor specific mutational signatures were observed. Our results do not support the pathogenicity of the analyzed POLD1 frameshift variant. One possible explanation is that haplosufficiency of the wild-type allele may be compensating for the absence of expression of the frameshift allele. Overall, future work is required to elucidate if functional consequences could be derived from POLD1 alterations different from missense variants in their proofreading domain. To our knowledge, our study presents the first organoid model for germline POLD1 variants and establishes the basis for its use as a model for disease in SPS, CRC and other malignancies.

Tumour break load is a biologically relevant feature of genomic instability with prognostic value in colorectal cancer

BACKGROUND

Clinically implemented prognostic biomarkers are lacking for the 80% of colorectal cancers (CRCs) that exhibit chromosomal instability (CIN). CIN is characterised by chromosome segregation errors and double-strand break repair defects that lead to somatic copy number aberrations (SCNAs) and chromosomal rearrangement-associated structural variants (SVs), respectively. We hypothesise that the number of SVs is a distinct feature of genomic instability and defined a new measure to quantify SVs: the tumour break load (TBL). The present study aimed to characterise the biological impact and clinical relevance of TBL in CRC.

METHODS

Disease-free survival and SCNA data were obtained from The Cancer Genome Atlas and two independent CRC studies. TBL was defined as the sum of SCNA-associated SVs. RNA gene expression data of microsatellite stable (MSS) CRC samples were used to train an RNA-based TBL classifier. Dichotomised DNA-based TBL data were used for survival analysis.

RESULTS

TBL shows large variation in CRC with poor correlation to tumour mutational burden and fraction of genome altered. TBL impact on tumour biology was illustrated by the high accuracy of classifying cancers in TBL-high and TBL-low (area under the receiver operating characteristic curve [AUC]: 0.88; p < 0.01). High TBL was associated with disease recurrence in 85 stages II-III MSS CRCs from The Cancer Genome Atlas (hazard ratio [HR]: 6.1; p = 0.007) and in two independent validation series of 57 untreated stages II-III (HR: 4.1; p = 0.012) and 74 untreated stage II MSS CRCs (HR: 2.4; p = 0.01).

CONCLUSION

TBL is a prognostic biomarker in patients with non-metastatic MSS CRC with great potential to be implemented in routine molecular diagnostics.

Immune Profiling of Peripheral Blood Mononuclear Cells at Pancreas Acute Rejection Episodes in Kidney-Pancreas Transplant Recipients

Profiling of circulating immune cells provides valuable insight to the pathophysiology of acute rejection in organ transplantation. Herein we characterized the peripheral blood mononuclear cells in simultaneous kidney-pancreas transplant recipients. We conducted a retrospective analysis in a biopsy-matched cohort (n = 67) and compared patients with biopsy proven acute rejection (BPAR; 41%) to those without rejection (No-AR). We observed that CD3+ T cells, both CD8+ and CD4+, as well as CD19+ B cells were increased in patients with BPAR, particularly in biopsies performed in the early post-transplant period (<3 months). During this period immune subsets presented a good discriminative ability (CD4+ AUC 0.79; CD8+ AUC 0.80; B cells AUC 0.86; p < 0.05) and outperformed lipase (AUC 0.62; p = 0.12) for the diagnosis of acute rejection. We further evaluated whether this could be explained by differences in frequencies prior to transplantation. Patients presenting with early post-transplant rejection (<3 months) had a significant increase in T-cell frequencies pre-transplant, both CD4+ T cells and CD8+ T cells (p < 0.01), which were associated with a significant inferior rejection-free graft survival. T cell frequencies in peripheral blood correlated with pancreas acute rejection episodes, and variations prior to transplantation were associated with pancreas early acute rejection.

In vivo computer-aided diagnosis of colorectal polyps using white light endoscopy

Background and study aims  Artificial intelligence is currently able to accurately predict the histology of colorectal polyps. However, systems developed to date use complex optical technologies and have not been tested in vivo. The objective of this study was to evaluate the efficacy of a new deep learning-based optical diagnosis system, ATENEA, in a real clinical setting using only high-definition white light endoscopy (WLE) and to compare its performance with endoscopists. Methods  ATENEA was prospectively tested in real life on consecutive polyps detected in colorectal cancer screening colonoscopies at Hospital Clínic. No images were discarded, and only WLE was used. The in vivo ATENEA's prediction (adenoma vs non-adenoma) was compared with the prediction of four staff endoscopists without specific training in optical diagnosis for the study purposes. Endoscopists were blind to the ATENEA output. Histology was the gold standard. Results  Ninety polyps (median size: 5 mm, range: 2-25) from 31 patients were included of which 69 (76.7 %) were adenomas. ATENEA correctly predicted the histology in 63 of 69 (91.3 %, 95 % CI: 82 %-97 %) adenomas and 12 of 21 (57.1 %, 95 % CI: 34 %-78 %) non-adenomas while endoscopists made correct predictions in 52 of 69 (75.4 %, 95 % CI: 60 %-85 %) and 20 of 21 (95.2 %, 95 % CI: 76 %-100 %), respectively. The global accuracy was 83.3 % (95 % CI: 74%-90 %) and 80 % (95 % CI: 70 %-88 %) for ATENEA and endoscopists, respectively. Conclusion  ATENEA can accurately be used for in vivo characterization of colorectal polyps, enabling the endoscopist to make direct decisions. ATENEA showed a global accuracy similar to that of endoscopists despite an unsatisfactory performance for non-adenomatous lesions.

A novel gene signature unveils three distinct immune-metabolic rewiring patterns conserved across diverse tumor types and associated with outcomes

Existing immune signatures and tumor mutational burden have only modest predictive capacity for the efficacy of immune check point inhibitors. In this study, we developed an immune-metabolic signature suitable for personalized ICI therapies. A classifier using an immune-metabolic signature (IMMETCOLS) was developed on a training set of 77 metastatic colorectal cancer (mCRC) samples and validated on 4,200 tumors from the TCGA database belonging to 11 types. Here, we reveal that the IMMETCOLS signature classifies tumors into three distinct immune-metabolic clusters. Cluster 1 displays markers of enhanced glycolisis, hexosamine byosinthesis and epithelial-to-mesenchymal transition. On multivariate analysis, cluster 1 tumors were enriched in pro-immune signature but not in immunophenoscore and were associated with the poorest median survival. Its predicted tumor metabolic features suggest an acidic-lactate-rich tumor microenvironment (TME) geared to an immunosuppressive setting, enriched in fibroblasts. Cluster 2 displays features of gluconeogenesis ability, which is needed for glucose-independent survival and preferential use of alternative carbon sources, including glutamine and lipid uptake/β-oxidation. Its metabolic features suggest a hypoxic and hypoglycemic TME, associated with poor tumor-associated antigen presentation. Finally, cluster 3 is highly glycolytic but also has a solid mitochondrial function, with concomitant upregulation of glutamine and essential amino acid transporters and the pentose phosphate pathway leading to glucose exhaustion in the TME and immunosuppression. Together, these findings suggest that the IMMETCOLS signature provides a classifier of tumors from diverse origins, yielding three clusters with distinct immune-metabolic profiles, representing a new predictive tool for patient selection for specific immune-metabolic therapeutic approaches.

Donor-derived Cell-free DNA Shows High Sensitivity for the Diagnosis of Pancreas Graft Rejection in Simultaneous Pancreas-kidney Transplantation

BACKGROUND

Pancreas graft status in simultaneous pancreas-kidney transplant (SPKTx) is currently assessed by nonspecific biochemical markers, typically amylase or lipase. Identifying a noninvasive biomarker with good sensitivity in detecting early pancreas graft rejection could improve SPKTx management.

METHODS

Here, we developed a pilot study to explore donor-derived cell-free DNA (dd-cfDNA) performance in predicting biopsy-proven acute rejection (P-BPAR) of the pancreas graft in a cohort of 36 SPKTx recipients with biopsy-matched plasma samples. dd-cfDNA was measured using the Prospera test (Natera, Inc.) and reported both as a fraction of the total cfDNA (fraction; %) and as concentration in the recipient's plasma (quantity; copies/mL).

RESULTS

In the absence of P-BPAR, dd-cfDNA was significantly higher in samples collected within the first 45 d after SPKTx compared with those measured afterward (median, 1.00% versus 0.30%; median, 128.2 versus 35.3 cp/mL, respectively with both; P  = 0.001). In samples obtained beyond day 45, P-BPAR samples presented a significantly higher dd-cfDNA fraction (0.83 versus 0.30%; P  = 0.006) and quantity (81.3 versus 35.3 cp/mL; P  = 0.001) than stable samples. Incorporating dd-cfDNA quantity along with dd-cfDNA fraction outperformed dd-cfDNA fraction alone to detect active rejection. Notably, when using a quantity cutoff of 70 cp/mL, dd-cfDNA detected P-BPAR with a sensitivity of 85.7% and a specificity of 93.7%, which was more accurate than current biomarkers (area under curve of 0.89 for dd-cfDNA (cp/ml) compared with 0.74 of lipase and 0.46 for amylase).

CONCLUSIONS

dd-cfDNA measurement through a simple noninvasive blood test could be incorporated into clinical practice to help inform graft management in SPKTx patients.

Differentially Deregulated MicroRNAs as Novel Biomarkers for Neoplastic Progression in Ulcerative Colitis

INTRODUCTION

Colorectal cancer (CRC) is a potentially life-threatening complication of long-standing ulcerative colitis (UC). MicroRNAs (miRNA) are epigenetic regulators that have been involved in the development of UC-associated CRC. However, their role as potential mucosal biomarkers of neoplastic progression has not been adequately studied.

METHODS

In this study, we analyzed the expression of 96 preselected miRNAs in human formalin-fixed and paraffin-embedded tissue of 52 case biopsies (20 normal mucosa, 20 dysplasia, and 12 UC-associated CRCs) and 50 control biopsies (10 normal mucosa, 21 sporadic adenomas, and 19 sporadic CRCs) by using Custom TaqMan Array Cards. For validation of deregulated miRNAs, we performed individual quantitative real-time polymerase chain reaction in an independent cohort of 50 cases (13 normal mucosa, 25 dysplasia, and 12 UC-associated CRCs) and 46 controls (7 normal mucosa, 19 sporadic adenomas, and 20 sporadic CRCs).

RESULTS

Sixty-four miRNAs were found to be differentially deregulated in the UC-associated CRC sequence. Eight of these miRNAs were chosen for further validation. We confirmed miR-31, -106a, and -135b to be significantly deregulated between normal mucosa and dysplasia, as well as across the UC-associated CRC sequence (all P < 0.01). Notably, these miRNAs also confirmed to have a significant differential expression compared with sporadic CRC (all P < 0.05).

DISCUSSION

UC-associated and sporadic CRCs have distinct miRNA expression patterns, and some miRNAs indicate early neoplastic progression.

Magnetic Resonance Enterography and Histology in Patients With Fibrostenotic Crohn's Disease: A Multicenter Study

INTRODUCTION

Magnetic resonance enterography (MRE) is useful for detecting bowel strictures, whereas a number of imaging biomarkers may reflect severity of fibrosis burden in Crohn's disease (CD). This study aimed to verify the association of MRE metrics with histologic fibrosis independent of inflammation.

METHODS

This prospective European multicenter study performed MRE imaging on 60 patients with CD with bowel strictures before surgical resection. Locations of 61 histological samples were annotated on MRE examinations, followed by central readings using the Chiorean score and measurement of delayed gain of enhancement (DGE), magnetization transfer ratio, T2-weighted MRI sequences (T2R), apparent diffusion coefficient (ADC), and the magnetic resonance index of activity (MaRIA). Correlations of histology and MRE metrics were assessed. Least Absolute Shrinkage and Selection Operator and receiver operator characteristic (ROC) curve analyses were used to select composite MRE scores predictive of histology and to estimate their predictive value.

RESULTS

ADC and MaRIA correlated with fibrosis (R = -0.71, P < 0.0001, and 0.59, P < 0.001) and more moderately with inflammation (R = -0.35, P < 0.01, and R = 0.53, P < 0.001). Lower or no correlations of fibrosis or inflammation were found with DGE, magnetization transfer ratio, or T2R. Least Absolute Shrinkage and Selection Operator and ROC identified a composite score of MaRIA, ADC, and DGE as a very good predictor of histologic fibrosis (ROC area under the curve = 0.910). MaRIA alone was the best predictor of histologic inflammation with excellent performance in identifying active histologic inflammation (ROC area under the curve = 0.966).

DISCUSSION

MRE-based scores for histologic fibrosis and inflammation may assist in the characterization of CD stenosis and enable development of fibrosis-targeted therapies and clinical treatment of stenotic patients.

Epigenome-Wide DNA Methylation Profiling of Normal Mucosa Reveals HLA-F Hypermethylation as a Biomarker Candidate for Serrated Polyposis Syndrome

Serrated polyposis syndrome (SPS) is associated with a high risk for colorectal cancer. Intense promoter hypermethylation is a frequent molecular finding in the serrated pathway and may be present in normal mucosa, predisposing to the formation of serrated lesions. To identify novel biomarkers for SPS, fresh-frozen samples of normal mucosa from 50 patients with SPS and 19 healthy individuals were analyzed by using the 850K BeadChip Technology (Infinium). Aberrant methylation levels were correlated with gene expression using a next-generation transcriptome profiling tool. Two validation steps were performed on independent cohorts: first, on formalin-fixed, paraffin-embedded tissue of the normal mucosa; and second, on 24 serrated lesions. The most frequently hypermethylated genes were HLA-F, SLFN12, HLA-DMA, and RARRES3; and the most frequently hypomethylated genes were PIWIL1 and ANK3 (Δβ = 10%; P < 0.05). Expression levels of HLA-F, SLFN12, and HLA-DMA were significantly different between SPS patients and healthy individuals and correlated well with the methylation status of the corresponding differentially methylated region (fold change, >20%; r > 0.55; P < 0.001). Significant hypermethylation of CpGs in the gene body of HLA-F was also found in serrated lesions (Δβ = 23%; false discovery rate = 0.01). Epigenome-wide methylation profiling has revealed numerous differentially methylated CpGs in normal mucosa from SPS patients. Significant hypermethylation of HLA-F is a novel biomarker candidate for SPS.

An Immune-metabolic signature (IMMETCOLS) identifies three clusters in mCRC with different immune-phenotype distribution and potential clinical implications

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Background: The overall response rate following immune check-point blockade (ICB) is < 5% in microsatellite stable (MSS) advanced colorectal cancer (mCRC), and between 30-35% in MSI mCRC. We here evaluate the relationship between our immune-metabolic signature (IMMETCOLS) distribution (cluster (IMC) 1; mesenchymal glycolytic, IMC 2; epithelial-non glycolytic and IMC 3; epithelial mitochondrial oxidative) with immune phenotypes (inflamed (IF), immune-excluded (IE) and immune-desert (ID)) in MSS and MSI mCRC patients (pts). Methods: We have analyzed IMMETCOLS in a retrospective cohort of 128 mCRC pts enriched with MSI-H and BRAF genotype using the nCounter platform (Nanostring Technologies, US). Immune phenotypes were evaluated by immunohistochemistry using 7 immune markers (CD68, CD163, CD8, CD3, FOXP3, PD-L1 and PD1) in a subset of 47 mCRC pts (27 MSS and 20 MSI), in TMAs containing 4 cores from the center of the tumor (CT) and invasive front (IF). The number of stained immune cells was counted using a computerized image analysis system, and PD-L1 was evaluated using CPS score (< 1 vs > 1). Patients having a CD3 cell count below 572 cells/mm2 and a CD8 density below 175 cells/mm2 in IF or CT were considered as ID. (Halama Nils, 2011). CD3 density was also semi-quantitatively estimated in peritumoral stroma and intra-tumoral (range 1-4), defining as IE those cases with a difference > 1 between the two regions in both IF and CT (Brooks JM, 2019). Results: Cluster distribution was similar between MSI (IMC1-40%, IMC2-20% and IMC-40%) and MSS (IMC1-34%, IMC2-24%, IMC3-43%) pts. Patients with high LDH levels (> 1.5ULN) were enriched with IMC3 phenotype (p < 0.0001). MSI have increased CD3 (p = 0.002), CD68 (p = 0.002) and CD163 (p = 0.001) in CT than MSS patients. IMC1 pts had increased CD163/CD68 ratio in CT (p = 0.004). 75% of MSI pts were IE and 25% IF. 55% of MSS pts were IE, 38% ID and 7% IF. IMMETCOLS/ immune-phenotype distribution was: IMC1 (16% ID/ 84% IE), IMC2 (12% ID/ 63% IE/ 25% IF) and IMC3 (35%ID/ 47% IE/ 18% IF). PD1 immuno-expression > 1% (IF and CT) and PD-L1 positivity was observed in 38%, 30% and 28% of pts respectively. There were no differences in PD-L1 (CPS) and PD1 expression between MSS and MSI tumors. Inflamed tumors show higher PD-L1 expression compared with IE and ID immune-phenotypes (p = 0.014). PD1 > 1% expression at IF was significatively lower in IMC1 vs IMC2 and IMC3 tumors (p = 0.032). Conclusions: IMC1 subtype is associated with low PD1 expression, high CD163/CD68 ratio and IE phenotype even in MSI-H mCRC patients. Therefore, IMMETCOLS testing would be of value to identify MSI mCRC pts that do not benefit to ICB therapy.

Patient Experience in Pancreas-Kidney Transplantation-A Methodological Approach Towards Innovation in an Established Program

Simultaneous pancreas-kidney transplantation (SPKT) leads to increased survival and quality of life, and is an alternative treatment for insulin-dependent diabetes mellitus and end-stage kidney disease. Due to the particularities of this population (often with multiple comorbidities) and of the surgery (only performed in a few centers), a comprehensive analysis of patients' experience along the SPKT process is crucial to improve patient care and add value to this procedure. Therefore, we applied a systematic and iterative methodology with the participation of both patients and professional teams working together to explore and identify unmet needs and value-adding steps along the transplant patient journey at an established pancreas transplant program. Four main steps (to comprehend, to explore, to experiment and to assess) led to several interventions around three major areas: Administration and logistics, information and communication, and perceived quality of assistance. As a result, both displacements to the hospital for diagnostic purposes and the time delay involved in joining the patient waiting list for transplantation were reduced in parallel to the administrative procedures. In conclusion, the methodological implementation of key organizational changes has great impact on overall patient experience. Further quantitative analysis from the patient's perspective will consolidate our program and may add new prototype service design components.

Copy-number intratumor heterogeneity increases the risk of relapse in chemotherapy-naive stage II colon cancer

Optimal selection of high-risk patients with stage II colon cancer is crucial to ensure clinical benefit of adjuvant chemotherapy. Here, we investigated the prognostic value of genomic intratumor heterogeneity and aneuploidy for disease recurrence. We combined targeted sequencing, SNP arrays, fluorescence in situ hybridization, and immunohistochemistry on a retrospective cohort of 84 untreated stage II colon cancer patients. We assessed the clonality of copy-number alterations (CNAs) and mutations, CD8⁺ lymphocyte infiltration, and their association with time to recurrence. Prognostic factors were included in machine learning analysis to evaluate their ability to predict individual relapse risk. Tumors from recurrent patients displayed a greater proportion of CNAs compared with non-recurrent (mean 31.3% versus 23%, respectively; p = 0.014). Furthermore, patients with elevated tumor CNA load exhibited a higher risk of recurrence compared with those with low levels [p = 0.038; hazard ratio (HR) 2.46], which was confirmed in an independent cohort (p = 0.004; HR 3.82). Candidate chromosome-specific aberrations frequently observed in recurrent cases included gain of the chromosome arm 13q (p = 0.02; HR 2.67) and loss of heterozygosity at 17q22-q24.3 (p = 0.05; HR 2.69). CNA load positively correlated with intratumor heterogeneity (R = 0.52; p < 0.0001). Consistently, incremental subclonal CNAs were associated with an elevated risk of relapse (p = 0.028; HR 2.20), which we did not observe for subclonal single-nucleotide variants and small insertions and deletions. The clinico-genomic model rated an area under the curve of 0.83, achieving a 10% incremental gain compared with clinicopathological markers (p = 0.047). In conclusion, tumor aneuploidy and copy-number intratumor heterogeneity were predictive of poor outcome and improved discriminative performance in early-stage colon cancer. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Impact of microscopic incomplete resection for colorectal liver metastases on surgical margin recurrence: R1-Contact vs R1 < 1 mm margin width

BACKGROUND

Several studies highlighted an inferior outcome of R1 resection for colorectal cancer liver metastases (CRLM); it is still unclear whether directly involved margins (R1-contact) are associated with a poorer outcome compared to R1 < 1 mm. The aim of this study is to analyze the impact on surgical margin recurrence (SMR) of R1-contact vs R1 < 1 mm patients.

METHODS

Patients who underwent surgery for CRLM between 2009-2018 with both R1 resections on final histology were included and compared in terms of recurrence and survival. Factors associated with SMR were assessed by univariate and multivariate analysis.

RESULTS

Out of 477, 77 (17.2%) patients showed R1 resection (53 R1-Contact and 24 R1 < 1 mm). Overall recurrence rate was 79.2% (R1 < 1 mm = 70.8% vs R1-contact group = 83%, P = .222). Median disease-free survival (DFS) and disease-specific survival (DSS) were significantly higher in R1 < 1 mm vs R1-contact group (93 vs 55 months; P = .025 and 69 vs 46 months; P = .038, respectively). The SMR rate was higher in R1-contact compared to R1 < 1 mm group (30.2% vs 8.3%; P = .036). At univariate analysis, age, number of metastases, open surgical approach, RAS status, and R1-contact were associated with SMR. At multivariate analysis, R1-contact margin was the only factor independently associated with higher SMR (OR = 5.6; P = .046).

CONCLUSIONS

R1-contact margin is independently associated with SMR after liver resection for CRLM. Patients with R1-contact margin will also experience poorer DFS and DSS.

Identification of Lynch Syndrome Carriers among Patients with Small Bowel Adenocarcinoma

Simple Summary

Small bowel adenocarcinoma (SBA) is associated with Lynch syndrome (LS). This is the first study to evaluate the identification of LS patients based on mismatch repair deficiency (MMRd) tumor among SBA. The authors found a 21.3% prevalence of MMRd tumors and a 10.1% prevalence of LS. A germline mutation was identified in 60% of patients with a MMRd tumor. This data suggests that universal tumor MMR testing among SBA patients should be implemented for the identification of LS.

Abstract

Background: Small bowel adenocarcinoma (SBA) is a rare disease which can be associated with Lynch syndrome (LS). LS tumors are characterized by the presence of microsatellite instability (MSI) and/or the loss of mismatch repair (MMR) protein expression. In SBA, the frequency of MMR deficient (MMRd) tumors varies from 5% to 35%. This study aims to describe the prevalence of LS carriers among patients with MMRd small bowel adenocarcinomas. Methods: A multicenter retrospective study with identification and MMR testing of all consecutive SBA between 2004 and 2020 in a multicenter Spanish study. Demographical data, tumor characteristics, follow-up and survival information were collected. Germline testing was driven by identification of MMRd tumors. Results: A total of 94 individuals diagnosed with SBA were recruited. We observed 20 (21.3%) MMRd tumors. In 9/15 (60%) patients with MMRd tumors, a pathogenic variant was identified (three MLH1, four MSH2, one MSH6 and one PMS2). Accordingly, the prevalence of LS among all SBA cases was 10.1%. Conclusions: More than one-fifth of SBA display MMRd and in more than a half is due to LS. Our data supports the implementation of universal MMR tumor testing among SBA for the identification of LS families.

KRAS phosphorylation regulates cell polarization and tumorigenic properties in colorectal cancer

Oncogenic mutations of KRAS are found in the most aggressive human tumors, including colorectal cancer. It has been suggested that oncogenic KRAS phosphorylation at Ser181 modulates its activity and favors cell transformation. Using nonphosphorylatable (S181A), phosphomimetic (S181D), and phospho-/dephosphorylatable (S181) oncogenic KRAS mutants, we analyzed the role of this phosphorylation to the maintenance of tumorigenic properties of colorectal cancer cells. Our data show that the presence of phospho-/dephosphorylatable oncogenic KRAS is required for preserving the epithelial organization of colorectal cancer cells in 3D cultures, and for supporting subcutaneous tumor growth in mice. Interestingly, gene expression differed according to the phosphorylation status of KRAS. In DLD-1 cells, CTNNA1 was only expressed in phospho-/dephosphorylatable oncogenic KRAS-expressing cells, correlating with cell polarization. Moreover, lack of oncogenic KRAS phosphorylation leads to changes in expression of genes related to cell invasion, such as SERPINE1, PRSS1,2,3, and NEO1, and expression of phosphomimetic oncogenic KRAS resulted in diminished expression of genes involved in enterocyte differentiation, such as HNF4G. Finally, the analysis, in a public data set of human colorectal cancer, of the gene expression signatures associated with phosphomimetic and nonphosphorylatable oncogenic KRAS suggests that this post-translational modification regulates tumor progression in patients.

Ex vivo Fusion Confocal Microscopy of Colorectal Polyps: A Fast Turnaround Time of Pathological Diagnosis

BACKGROUND

Colorectal cancer screening programs have accomplished a mortality reduction from the disease but have created bottlenecks in endoscopy units and pathology departments. We aimed to explore the feasibility of ex vivo fusion confocal microscopy (FuCM) to improve the histopathology diagnostic efficiency and reduce laboratory workload.

METHODS

Consecutive fresh polyps removed at colonoscopy were scanned using ex vivo FuCM, then went through histopathologic workout and hematoxylin and eosin (H&amp;E) diagnosis. Two pathologists blinded to H&amp;E diagnosis made a diagnosis based on FuCM scanned images.

RESULTS

Thirty-six fresh polyps from 22 patients were diagnosed with FuCM and H&amp;E. Diagnostic agreement between H&amp;E and FuCM was 97.2% (kappa = 0.96) for pathologist #1 and 91.7% (kappa = 0.87) for pathologist #2. Diagnostic performance concordance between FuCM and H&amp;E to discern adenomatous from nonadenomatous polyps was 100% (kappa = 1) for pathologist #1 and 97.2% (kappa = 0.94) for pathologist #2. Global interobserver agreement was 94.44% (kappa = 0.91) and kappa = 0.94 to distinguish adenomatous from nonadenomatous polyps.

CONCLUSIONS

Ex vivo FuCM shows an excellent correlation with standard H&amp;E for the diagnosis of colorectal polyps. The clinical direct benefit for patients, pathologists, and endoscopists allows adapting personalized surveillance protocols after colonoscopy and a workload decrease in pathology departments.

Diagnosis of Helicobacter pylori Infection by the Arrangement of Collecting Venules Using White Light Endoscopy: Evaluation of Interobserver Agreement

BACKGROUND

Regular arrangement of collecting venules (RAC) in gastric mucosa accurately identifies patients without Helicobacter pylori (H pylori) infection. The aim of our study was to evaluate the reproducibility of RAC using white light endoscopy without magnification, in a European country, and to assess the impact of proton pump inhibitors (PPIs).

METHODS

A multicenter prospective study with image capture of the distal lesser gastric curvature and gastric biopsies was performed. The presence of starfish-like minute points regularly distributed throughout lesser curvature was considered as RAC positive (RAC+). A set of 20 images was used for the training phase and inter and intra-observer agreements were calculated.

RESULTS

174 patients were included and 85 (48.9%) were taking PPIs. Kappa values for interobserver and intra-observer agreements were substantial (0.786) and excellent (0.906), respectively. H. pylori infection was diagnosed in 29 patients (16.7%): 10/85 with PPIs and 19/89 without PPIs (11.8% vs. 21.3%; p = 0.09). All RAC + patients were free of H. pylori infection, with a sensitivity and negative predictive value of 100%, regardless of PPI intake.

CONCLUSION

The endoscopic diagnosis of H. pylori by RAC is an easy-to-learn and highly reproducible technique, even with PPI intake. Our results warrant RAC as a real-time diagnostic method for H. pylori-negative infection in Western practice.

Clinical, Molecular and Genetic Characteristics of Early Onset Gastric Cancer: Analysis of a Large Multicenter Study

Gastric adenocarcinoma (GC) is a common tumor with high morbidity and mortality. Only 7% of patients with GC are diagnosed before age 50 (early onset gastric cancer (EOGC)), and their characteristics have been poorly described. We aimed to describe clinical, molecular, and genetic characteristics of EOGC. A total of 309 patients with EOGC were retrospectively studied in four Spanish centers. Personal information, family history, and tumor information were registered. Germinal genetic analysis was performed in patients who met current criteria of a hereditary syndrome at the time of diagnosis. The median age at diagnosis was 44 years. The majority (73.3%) of tumors were diffuse, and 78.3% were diagnosed in an advanced stage. Familial aggregation of GC was present in 18/117 (15.4%) cases, and 5/117 (4.3%) met criteria for familial GC. MMR-IHC was performed in 126/309 (40.7%) tumors: 4/126 (3.1%) had loss of expression in MLH1/PMS2, without an associated germline mutation. Sixteen germline genetic analyses were performed, detecting a pathogenic variant in four (25%) cases: one in BRCA2, one in TP53, and two in CDH1. Most EOGC are diffuse and diagnosed in an advanced stage. In these patients, DNA MMR system deficiency is uncommon. Although familial aggregation was observed in only 15% of cases, a germline mutation was found in 25% of patients tested with clinical criteria. This demonstrates that EOGC has a marked genetic heterogeneity, reinforcing the importance of an accurate genetic counseling and enhancing the emerging use of multigene panels.

Zeb1 induces immune checkpoints to form an immunosuppressive envelope around invading cancer cells

The PDL1-PD1 immune checkpoint inhibits T cell activation, and its blockade is effective in a subset of patients. Studies are investigating how checkpoints are hijacked by cancer cells and why most patients remain resistant to immunotherapy. Epithelial mesenchymal transition (EMT), which drives tumor cell invasion via the Zeb1 transcription factor, is linked to immunotherapy resistance. In addition, M2-polarized tumor-associated macrophages (TAMs), which inhibit T cell migration and activation, may also cause immunotherapy resistance. How EMT in invading cancer cells is linked to therapy resistance and events driving TAM M2 polarization are therefore important questions. We show that Zeb1 links these two resistance pathways because it is required for PDL1 expression on invading lung cancer cells, and it also induces CD47 on these invading cells, which drives M2 polarization of adjacent TAMs. Resulting reprogramming of the microenvironment around invading cells shields them from the hostile inflammatory environment surrounding tumors.

Description of the genetic variants identified in a cohort of patients diagnosed with localized anal squamous cell carcinoma and treated with panitumumab

Squamous cell carcinoma is the most frequent histologic type of anal carcinoma. The standard of care since the 1970s has been a combination of 5-fluorouracil, mitomycin C, and radiotherapy. This treatment is very effective in T1/T2 tumors (achieving complete regression in 80–90% of tumors). However, in T3/T4 tumors, the 3-year relapse free survival rate is only 50%. The VITAL trial aimed to assess the efficacy and safety of panitumumab in combination with this standard treatment. In this study, 27 paraffin-embedded samples from the VITAL trial and 18 samples from patients from daily clinical practice were analyzed by whole-exome sequencing and the influence of the presence of genetic variants in the response to panitumumab was studied. Having a moderate- or high-impact genetic variant in PIK3CA seemed to be related to the response to panitumumab. Furthermore, copy number variants in FGFR3, GRB2 and JAK1 were also related to the response to panitumumab. These genetic alterations have also been studied in the cohort of patients from daily clinical practice (not treated with panitumumab) and they did not have a predictive value. Therefore, in this study, a collection of genetic alterations related to the response with panitumumab was described. These results could be useful for patient stratification in new anti-EGFR clinical trials.

Improving tumor budding reporting in colorectal cancer: a Delphi consensus study

Tumor budding is a long-established independent adverse prognostic marker in colorectal cancer, yet methods for its assessment have varied widely. In an effort to standardize its reporting, a group of experts met in Bern, Switzerland, in 2016 to reach consensus on a single, international, evidence-based method for tumor budding assessment and reporting (International Tumor Budding Consensus Conference [ITBCC]). Tumor budding assessment using the ITBCC criteria has been validated in large cohorts of cancer patients and incorporated into several international colorectal cancer pathology and clinical guidelines. With the wider reporting of tumor budding, new issues have emerged that require further clarification. To better inform researchers and health-care professionals on these issues, an international group of experts in gastrointestinal pathology participated in a modified Delphi process to generate consensus and highlight areas requiring further research. This effort serves to re-affirm the importance of tumor budding in colorectal cancer and support its continued use in routine clinical practice.

Lymph Node Tumor Burden Correlates With Tumor Budding and Poorly Differentiated Clusters: A New Prognostic Factor in Colorectal Carcinoma?

INTRODUCTION

Molecular lymph node (LN) staging in early colorectal cancer (CRC) has demonstrated to be more precise than conventional histopathology pN staging. Tumor budding (TB) and poorly differentiated clusters (PDCs) are associated with LN metastases, recurrences, and lower survival in CRC. We evaluated the correlation between the total tumor load (TTL) in LNs from CRC surgical specimens with patient outcome, TB, and PDC.

METHODS

In this retrospective multicentre study, 5,931 LNs from 342 stage I-III CRC were analyzed by both hematoxylin and eosin and molecular detection of tumor cytokeratin 19 mRNA by one-step nucleic acid amplification. TB and PDC were evaluated by hematoxylin and eosin and cytokeratin 19 immunohistochemistry.

RESULTS

One-step nucleic acid was positive in 38.3% patients (n = 131). Tumor Budding was low in 45% cases, intermediate in 25%, and high in 30%. Poorly Differentiated Clusters were low-grade G1 in 53%, G2 in 32%, and G3 in 15%. TB and PDC correlated with TTL, high-grade, lymphovascular and perineural invasion, pT, pN and stage (P < 0.001). TB, PDC, and TTL ≥ 6,000 copies/µL were associated with worse overall survival (P = 0.002, P = 0.013, and P = 0.046) and disease-free survival (P < 0.001).

DISCUSSION

The implementation of more sensitive molecular methods to assess LN status is a promising alternative approach to pN staging, which could be integrated to other factors to help risk stratification and management of patients with early-stage CRC. This study demonstrates the correlation of the amount of LN tumor burden with TB and PDCs. TTL is related to the outcome and could be used as a new prognostic factor in CRC (see Visual Abstract, Supplementary Digital Content 2, http://links.lww.com/CTG/A512).

Germline and Somatic Whole-Exome Sequencing Identifies New Candidate Genes Involved in Familial Predisposition to Serrated Polyposis Syndrome

The serrated polyposis syndrome (SPS) is the most common and yet underdiagnosed colorectal polyposis syndrome. It is characterized by multiple and/or large colonic serrated polyps and a higher associated risk for colorectal cancer (CRC). The main objective of this study was to identify new candidate genes involved in the germline predisposition to SPS/CRC. Thirty-nine SPS patients from 16 families (≥2 patients per family) were recruited without alterations in well-known hereditary CRC genes, and germline and somatic whole-exome sequencing were performed. Germline rare variants with plausible pathogenicity, located in genes involved in cancer development, senescence and epigenetic regulation were selected. Somatic mutational profiling and signature analysis was pursued in one sample per family, when possible. After data filtering, ANXA10, ASXL1, CFTR, DOT1L, HIC1, INO80, KLF3, MCM3AP, MCM8, PDLIM2, POLD1, TP53BP1, WNK2 and WRN were highlighted as the more promising candidate genes for SPS germline predisposition with potentially pathogenic variants shared within families. Somatic analysis characterized mutational profiles in advanced serrated polyps/tumors, revealing a high proportion of hypermutated samples, with a prevalence of clock-like mutational signatures in most samples and the presence of DNA mismatch repair-defective signatures in some cases. In conclusion, we identified new candidate genes to be involved in familial SPS. Further functional studies and replication in additional cohorts are required to confirm the selected candidates.

Quality in diagnostic upper gastrointestinal endoscopy for the detection and surveillance of gastric cancer precursor lesions: Position paper of AEG, SEED and SEAP

This position paper, sponsored by the Asociación Española de Gastroenterología [Spanish Association of Gastroenterology], the Sociedad Española de Endoscopia Digestiva [Spanish Gastrointestinal Endoscopy Society] and the Sociedad Española de Anatomía Patológica [Spanish Anatomical Pathology Society], aims to establish recommendations for performing an high quality upper gastrointestinal endoscopy for the screening of gastric cancer precursor lesions (GCPL) in low-incidence populations, such as the Spanish population. To establish the quality of the evidence and the levels of recommendation, we used the methodology based on the GRADE system (Grading of Recommendations Assessment, Development and Evaluation). We obtained a consensus among experts using a Delphi method. The document evaluates different measures to improve the quality of upper gastrointestinal endoscopy in this setting and makes recommendations on how to evaluate and treat the identified lesions. We recommend that upper gastrointestinal endoscopy for surveillance of GCPL should be performed by endoscopists with adequate training, administering oral premedication and use of sedation. To improve the identification of GCPL, we recommend the use of high definition endoscopes and conventional or digital chromoendoscopy and, for biopsies, NBI should be used to target the most suspicious areas of intestinal metaplasia. Regarding the evaluation of visible lesions, the risk of submucosal invasion should be evaluated with magnifying endoscopes and endoscopic ultrasound should be reserved for those with suspected deep invasion. In lesions amenable to endoscopic resection, submucosal endoscopic dissection is considered the technique of choice.

Clinical impact of preoperative tumour contact with superior mesenteric-portal vein in patients with resectable pancreatic head cancer

INTRODUCTION

The NCCN classification of resectability in pancreatic head cancer does not consider preoperative radiological tumour ≤ 180° contact with portal vein/superior mesenteric vein (PV/SMV) as a negative prognostic feature. The aim of this study is to evaluate whether this factor is associated with higher rate of incomplete resection and poorer survival.

METHODS

All patients considered for pancreatic resection between 2012 and 2017 at two Spanish referral centres were included. Patients with borderline and locally advanced pancreatic ductal adenocarcinoma (PDAC) according to NCCN classification were excluded. Preoperative CT scans were reviewed by dedicated radiologists to identify radiologic tumour contact with PV/SMV.

RESULTS

Out of 302, 71 patients were finally included in this study. Twenty-two (31%) patients showed tumour-PV/SMV contact (group 1) and 49 (69%) did not show any contact (group 2). Patients in group 1 showed a statistically significantly higher rate of R1 and R1-direct margins compared with group 2 (95 vs 28% and 77 vs 10%) and lower median survival (24 vs 41 months, p = 0.02). Preoperative contact with PV/SMV, lymph node metastases, R1-direct margin and NO adjuvant chemotherapy were significantly associated with disease-specific survival at multivariate analysis.

CONCLUSION

Preoperative radiological tumour contact with PV/SMV in patients with NCCN resectable PDAC is associated with high rate of pathologic positive margins following surgery and poorer survival.

Early intestinal complications following pancreas transplantation: lessons learned from over 300 cases - a retrospective single-center study

Enteric complications remain a major cause of morbidity in the post-transplant period of pancreas transplantation despite improvements surgical technique. The aim of this single-center study was to analyze retrospectively the early intestinal complications and their potential relation with vascular events. From 2000 to 2016, 337 pancreas transplants were performed with systemic venous drainage. For exocrine secretion, intestinal drainage was done with hand-sewn anastomosis duodenojejunostomy. Twenty-three patients (6.8%) had early intestinal complications. Median age was 39 years (male: 65.2%). Median cold ischemia time was 11 h [IQR: 9-12.4]. Intestinal complications were intestinal obstruction (n = 7); paralytic ileus (n = 5); intestinal fistula without anastomotic dehiscence (n = 3); ischemic graft duodenum (n = 3); dehiscence of duodenojejunostomy (n = 4); and anastomotic dehiscence in jejunum after pancreas transplantectomy (n = 1). Eighteen cases required relaparotomy: adhesiolysis (n = 6); repeated laparotomy without findings (n = 1); transplantectomy (n = 6); primary leak closure (n = 3); re-positioning of the graft (n = 1); and intestinal resection (n = 1). Of the intestinal complications, 4 were associated with vascular thrombosis, resulting in two pancreatic graft losses. Enteric drainage with duodenum-jejunum anastomosis is safe and feasible, with a low rate of intra-abdominal complications. Vascular thrombosis associated with intestinal complications presents a risk factor for the viability of pancreatic grafts, so prevention and early detection is vital.

[Update of the recommendations for the determination of biomarkers in colorectal carcinoma. National Consensus of the Spanish Society of Medical Oncology and the Spanish Society of Pathology]

This update of the consensus of the Spanish Society of Medical Oncology (Sociedad Española de Oncología Médica - SEOM) and the Spanish Society of Pathology (Sociedad Española de Anatomía Patológica - SEAP), reviews the advances in the analysis of biomarkers in advanced colorectal cancer (CRC) as well as susceptibility markers of hereditary CRC and molecular biomarkers of localized CRC. Recently published information on the essential determination of KRAS, NRAS and BRAF mutations and the possible benefits of determining the amplification of human epidermal growth factor receptor 2 (HER2), the expression of proteins in the DNA repair pathway and the study of NTRK fusions are also evaluated. From a pathological point of view, the importance of analysing the tumour budding and poorly differentiated clusters and its prognostic value in CRC is reviewed, as well as the impact of molecular lymph node analysis on lymph node staging in CRC. The incorporation of pan-genomic technologies, such as next-generation sequencing (NGS) and liquid biopsy in the clinical management of patients with CRC is also outlined. All these aspects are developed in this guide which, like the previous one, will be revised when necessary in the future.

Germline biallelic Mcm8 variants are associated with early-onset Lynch-like syndrome

Lynch syndrome is the most common cause of hereditary colorectal cancer (CRC), and it is characterized by DNA mismatch repair (MMR) deficiency. The term Lynch-like syndrome (LLS) is used for patients with MMR-deficient tumors and neither germline mutation in MLH1, MSH2, MSH6, PMS2, or EPCAM nor MLH1 somatic methylation. Biallelic somatic inactivation or cryptic germline MMR variants undetected during genetic testing have been proposed to be involved. Sixteen patients with early-onset LLS CRC were selected for germline and tumor whole-exome sequencing. Two potentially pathogenic germline MCM8 variants were detected in a male patient with LLS with fertility problems. A knockout cellular model for MCM8 was generated by CRISPR/Cas9 and detected genetic variants were produced by mutagenesis. DNA damage, microsatellite instability, and mutational signatures were monitored. DNA damage was evident for MCM8^KO cells and the analyzed genetic variants. Microsatellite instability and mutational signatures in MCM8^KO cells were compatible with the involvement of MCM8 in MMR. Replication in an independent familial cancer cohort detected additional carriers. Unexplained MMR-deficient CRC cases, even showing somatic biallelic MMR inactivation, may be caused by underlying germline defects in genes different than MMR genes. We suggest MCM8 as a gene involved in CRC germline predisposition with a recessive pattern of inheritance.

MCM8 may be involved in germline predisposition to colorectal cancer in Lynch-like syndrome cases.