Comprehensive genomic and transcriptomic characterization of high-grade gastro-entero-pancreatic neoplasms

BACKGROUND

High-grade gastro-entero-pancreatic neoplasms (HG GEP-NENs) can be stratified according to their morphology and Ki-67 values into three prognostic classes: neuroendocrine tumors grade 3 (NETs G3), neuroendocrine carcinomas with Ki-67 < 55% (NECs <55) and NECs with Ki-67 ≥ 55% (NECs ≥55).

METHODS

We analyzed a cohort of 49 HG GEP-NENs by targeted Next-Generation Sequencing (TrueSight Oncology 500), RNA-seq, and immunohistochemistry for p53, Rb1, SSTR-2A, and PD-L1.

RESULTS

Frequent genomic alterations affected TP53 (26%), APC (20%), KRAS and MEN1 (both 11%) genes. NET G3 were enriched in MEN1 (p = 0.02) mutations, while both NECs groups were enriched in TP53 (p = 0.001), APC (p = 0.002) and KRAS (p = 0.02) mutations and tumors with TMB ≥ 10 muts/Mb (p = 0.01). No differentially expressed (DE) gene was found between NECs <55% and NECs ≥55%, while 1129 DE genes were identified between NET G3 and NECs. A slight enrichment of CD4+ and CD8+ T cells in NECs and of cancer-associated fibroblasts and macrophages (M2-like) in NET G3. Multivariate analysis identified histologic type and Rb1 loss as independent prognostic factors for overall survival.

CONCLUSIONS

This study showed that GEP-NET G3 and GEP-NECs exhibit clear genomic and transcriptomic differences, differently from GEP-NECs <55% and GEP-NECs ≥55%, and provided molecular findings with prognostic and potentially predictive value.

IMMUNOREACT 7: Regular aspirin use is associated with immune surveillance activation in colorectal cancer

BACKGROUND

Long-term daily use of aspirin reduces incidence and mortality due to colorectal cancer (CRC). This study aimed to analyze the effect of aspirin on the tumor microenvironment, systemic immunity, and on the healthy mucosa surrounding cancer.

METHODS

Patients with a diagnosis of CRC operated on from 2015 to 2019 were retrospectively analyzed (METACCRE cohort). Expression of mRNA of immune surveillance-related genes (PD-L1, CD80, CD86, HLA I, and HLA II) in CRC primary cells treated with aspirin were extracted from Gene Expression Omnibus-deposited public database (GSE76583). The experiment was replicated in cell lines. The mucosal immune microenvironment of a subgroup of patients participating in the IMMUNOREACT1 (ClinicalTrials.gov NCT04915326) project was analyzed with immunohistochemistry and flow cytometry.

RESULTS

In the METACCRE Cohort, 12% of 238 patients analyzed were aspirin users. Nodal metastasis was significantly less frequent (p = .008) and tumor-infiltrating lymphocyte infiltration was higher (p = .02) among aspirin users. In the CRC primary cells and selected cell lines, CD80 mRNA expression was increased following aspirin treatment (p = .001). In the healthy mucosa surrounding rectal cancer, the ratio of CD8/CD3 and epithelial cells expressing CD80 was higher in aspirin users (p = .027 and p = .034, respectively).

CONCLUSIONS

These data suggested that regular aspirin use may have an active role in enhancing immunosurveillance against CRC.

IMMUNOREACT 6: weak immune surveillance characterizes early-onset rectal cancer

BACKGROUND

Colon cancer in young patients is often associated with hereditary syndromes; however, in early-onset rectal cancer, mutations of these genes are rarely observed. The aim of this study was to analyse the features of the local immune microenvironment and the mutational pattern in early-onset rectal cancer.

METHODS

Commonly mutated genes were analysed within a rectal cancer series from the University Hospital of Padova. Mutation frequency and immune gene expression in a cohort from The Cancer Genome Atlas ('TCGA') were compared and immune-cell infiltration levels in the healthy rectal mucosa adjacent to rectal cancers were evaluated in the IMMUNOlogical microenvironment in REctal AdenoCarcinoma Treatment 1 and 2 ('IMMUNOREACT') series.

RESULTS

In the authors' series, the mutation frequency of BRAF, KRAS, and NRAS, as well as microsatellite instability frequency, were not different between early- and late-onset rectal cancer. In The Cancer Genome Atlas series, among the genes with the most considerable difference in mutation frequency between young and older patients, seven genes are involved in the immune response and CD69, CD3, and CD8β expression was lower in early-onset rectal cancer. In the IMMUNOlogical microenvironment in REctal AdenoCarcinoma Treatment 1 and 2 series, young patients had a lower rate of CD4+ T cells, but higher T regulator infiltration in the rectal mucosa.

CONCLUSION

Early-onset rectal cancer is rarely associated with common hereditary syndromes. The tumour microenvironment is characterized by a high frequency of mutations impairing the local immune surveillance mechanisms and low expression of immune editing-related genes. A constitutively low number of CD4 T cells associated with a high number of T regulators indicates an imbalance in the immune surveillance mechanisms.

Abstract 1005: LINE-1 hypomethylation is associated with poor outcomes in locoregionally advanced oropharyngeal cancer

Background: Currently, human papillomavirus (HPV) positivity represents a strong prognostic factor for both reduced risk of relapse and improved survival in patients with oropharyngeal squamous cell carcinoma (OPSCC). However, a subset of HPV-positive OPSCC patients still experience poor outcomes. Furthermore, HPV-negative OPSCC patients, who have an even higher risk of relapse, are still lacking suitable prognostic biomarkers for clinical outcome. Here, we evaluated the prognostic value of LINE-1 methylation level in OPSCC patients, and further addressed the relationship between LINE-1 methylation status and p53 protein expression as well as genome-wide/gene-specific DNA methylation.

Results: In this study, DNA was extracted from 163 formalin-fixed paraffin-embedded tissue samples retrospectively collected from stage III-IVB OPSCC patients managed with curative intent with up-front treatment. Quantitative methylation-specific PCR revealed that LINE-1 hypomethylation was directly associated with poor prognosis (5-year overall survival - OS: 28.1% for LINE-1 methylation&lt;35% versus 69.1% for ≥55%; p&lt;0.0001). When LINE-1 methylation was dichotomized as &lt;55% vs. ≥55%, interaction with HPV16 emerged: compared with hypermethylated HPV-16 positive patients, subjects with hypomethylated HPV16-negative OPSCC reported an adjusted higher risk of death (HR: 4.83, 95% CI: 2.24-10.38) and progression (HR: 4.54, 95% CI: 2.18-9.48). Tumor protein p53 (TP53) gene is often mutated and overexpressed in HPV-negative OPSCC. Since p53 has been reported to repress LINE-1 promoter, we then analyzed the association between p53 protein expression and LINE-1 methylation levels. Following p53 immunohistochemistry, results indicated that among HPV16-negative patients with p53≥50%, LINE-1 methylation levels declined and remained stable at approximately 43%; any HPV16-positive patient reported p53≥50%. Finally, DNA methylation analysis demonstrated that genome-wide average methylation level at cytosine-phosphate-guanine sites was significantly lower in HPV16-negative OPSCC patients who relapsed within two years. The subsequent integrative analysis of gene expression and DNA methylation identified 20 up-regulated/hypomethylated genes in relapsed patients, and most of them contained LINE-1 elements in their promoter sequences.

Conclusions: Evaluation of the methylation level of LINE-1 may help in identifying the subset of OPSCC patients with bad prognosis regardless of their HPV status. Aberrant LINE-1 hypomethylation might occur along with TP53 mutations, and lead to altered gene expression in OPSCC.

Citation Format: Mariateresa Casarotto, Valentina Lupato, Giorgio Giurato, Roberto Guerrieri, Sandro Sulfaro, Annamaria Salvati, Elisa D'Angelo, Carlo Furlan, Anna Menegaldo, Lorena Baboci, Barbara Montico, Irene Turturici, Riccardo Dolcetti, Salvatore Romeo, Vittorio Baggio, Stefania Corrado, Gianluca Businello, Maria Guido, Alessandro Weisz, Vittorio Giacomarra, Giovanni Franchin, Agostino Steffan, Luca Sigalotti, Emanuela Vaccher, Paolo Boscolo-Rizzo, Jerry Polesel, Giuseppe Fanetti, Elisabetta Fratta. LINE-1 hypomethylation is associated with poor outcomes in locoregionally advanced oropharyngeal 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 1005.

IMMUNOREACT 5: female patients with rectal cancer have better immune editing mechanisms than male patients – a cohort study

BACKGROUND

Studies evaluating sex differences in colorectal cancer (CRC) tumor microenvironment are limited, and no previous study has focused on rectal cancer patients' constitutive immune surveillance mechanisms. The authors aimed to assess gender-related differences in the immune microenvironment of rectal cancer patients.

METHODS

A systematic review and meta-analysis were conducted up to 31 May 2021, including studies focusing on gender-related differences in the CRC tumor microenvironment. Data on the mutational profile of rectal cancer were extracted from the Cancer Genome Atlas (TCGA). A subanalysis of the two IMMUNOREACT trials (NCT04915326 and NCT04917263) was performed, aiming to detect gender-related differences in the immune microenvironment of the healthy mucosa in patients with early (IMMUNOREACT 1 cohort) and locally advanced rectal cancer following neoadjuvant therapy (IMMUNOREACT 2 cohort). In the retrospective IMMUNOREACT 1 cohort (therapy naive), the authors enrolled 442 patients (177 female and 265 male), while in the retrospective IMMUNOREACT 2 cohort (patients who had neoadjuvant therapy), we enrolled 264 patients (80 female and 184 male). In the prospective IMMUNOREACT 1 cohort (therapy naive), the authors enrolled 72 patients (26 female and 46 male), while in the prospective IMMUNOREACT 2 cohort (patients who had neoadjuvant therapy), the authors enrolled 105 patients (42 female and 63 male).

RESULTS

Seven studies reported PD-L1 expression in the CRC microenvironment, but no significant difference could be identified between the sexes. In the TGCA series, mutations of SYNE1 and RYR2 were significantly more frequent in male patients with rectal cancer. In the IMMUNOREACT 1 cohort, male patients had a higher expression of epithelial cells expressing HLA class I, while female patients had a higher number of activated CD4+Th1 cells. Female patients in the IMMUNOREACT 2 cohort showed a higher infiltration of epithelial cells expressing CD86 and activated cytotoxic T cells (P=0.01).

CONCLUSIONS

Male patients have more frequent oncogene mutations associated with a lower expression of T-cell activation genes. In the healthy mucosa of female patients, more Th1 cells and cytotoxic T cells suggest a potentially better immune response to the tumor. Sex should be considered when defining the treatment strategy for rectal cancer patients or designing prognostic scores.

Colorectal adenosquamous carcinoma: genomic profiling of a rare histotype of colorectal cancer

Colorectal adenosquamous carcinoma (ASC) is exceedingly rare, comprising less than 0.1% of all colorectal malignancies, and is characterized by an aggressive disease course, with a higher metastatic rate and worse outcome than conventional colorectal adenocarcinoma. A comprehensive molecular profile of this group of neoplasms is still lacking. A total of 22 cases of colorectal ASCs (with 22 primary lesions and 7 metastases matched with 4 primaries) were subject to NGS targeting 67 cancer-related genes (VariantPlex solid tumor; Archer). Mismatch repair (MMR), p53, and ^V600EBRAF status were also investigated by immunohistochemistry. In 28 of 29 (96.6%) ASC samples, at least one single-nucleotide variant (SNV) or copy number variation (CNV) was detected. Among the 22 primary tumors, the most frequently mutated genes were TP53 (59.1%), APC (40.9%), KRAS (27.3%), BRAF (13.6%), and GNAS (9.1%). Only 1/22 (4.5%) primary ASC was MMR-deficient (MMRd) and harbored a BRAF mutation. Limited differences in SNVs were observed between primary and metastatic diseases. This study sheds light on the molecular landscape of colorectal ASCs. According to our data, the genomic profile of colorectal ASC is similar to that of conventional colorectal carcinoma, with significant druggable genetic alterations. Further studies are required to understand the more aggressive clinical behavior of this neoplasm.

LINE-1 hypomethylation is associated with poor outcomes in locoregionally advanced oropharyngeal cancer

BACKGROUND AND PURPOSE

Currently, human papillomavirus (HPV) positivity represents a strong prognostic factor for both reduced risk of relapse and improved survival in patients with oropharyngeal squamous cell carcinoma (OPSCC). However, a subset of HPV-positive OPSCC patients still experience poor outcomes. Furthermore, HPV-negative OPSCC patients, who have an even higher risk of relapse, are still lacking suitable prognostic biomarkers for clinical outcome. Here, we evaluated the prognostic value of LINE-1 methylation level in OPSCC patients and further addressed the relationship between LINE-1 methylation status and p53 protein expression as well as genome-wide/gene-specific DNA methylation.

RESULTS

In this study, DNA was extracted from 163 formalin-fixed paraffin-embedded tissue samples retrospectively collected from stage III-IVB OPSCC patients managed with curative intent with up-front treatment. Quantitative methylation-specific PCR revealed that LINE-1 hypomethylation was directly associated with poor prognosis (5-year overall survival-OS: 28.1% for LINE-1 methylation < 35% vs. 69.1% for ≥ 55%; p < 0.0001). When LINE-1 methylation was dichotomized as < 55% versus ≥ 55%, interaction with HPV16 emerged: compared with hypermethylated HPV16-positive patients, subjects with hypomethylated HPV16-negative OPSCC reported an adjusted higher risk of death (HR 4.83, 95% CI 2.24-10.38) and progression (HR 4.54, 95% CI 2.18-9.48). Tumor protein p53 (TP53) gene is often mutated and overexpressed in HPV-negative OPSCC. Since p53 has been reported to repress LINE-1 promoter, we then analyzed the association between p53 protein expression and LINE-1 methylation levels. Following p53 immunohistochemistry, results indicated that among HPV16-negative patients with p53 ≥ 50%, LINE-1 methylation levels declined and remained stable at approximately 43%; any HPV16-positive patient reported p53 ≥ 50%. Finally, DNA methylation analysis demonstrated that genome-wide average methylation level at cytosine-phosphate-guanine sites was significantly lower in HPV16-negative OPSCC patients who relapsed within two years. The subsequent integrative analysis of gene expression and DNA methylation identified 20 up-regulated/hypomethylated genes in relapsed patients, and most of them contained LINE-1 elements in their promoter sequences.

CONCLUSIONS

Evaluation of the methylation level of LINE-1 may help in identifying the subset of OPSCC patients with bad prognosis regardless of their HPV status. Aberrant LINE-1 hypomethylation might occur along with TP53 mutations and lead to altered gene expression in OPSCC.

Histopathological Landscape of Precursor Lesions of Gastro-Entero-Pancreatic Neuroendocrine Neoplasms

BACKGROUND

Despite the important advances in research on neuroendocrine neoplasms of the gastro-entero-pancreatic tract, their precursor lesions are much less well known.

SUMMARY

This review analyzes the preneoplastic neuroendocrine lesions of the gastro-entero-pancreatic tract, by adopting a coherent anatomical benchmark. In particular, the settings in which neuroendocrine precursor lesions represent well-recognized pathophysiological and morphological entities (with eventual molecular correlates) have been distinguished from the ones in which the nature of preneoplastic changes is still obscure.

KEY MESSAGES

The aim of the paper was to summarize what is known about precursor lesions of gastro-entero-pancreatic neuroendocrine tumors, with the goal of providing a useful tool for future research aimed at obtaining a fuller understanding of the underlying biology and early development of these diseases.

Multi-Design Differential Expression Profiling of COVID-19 Lung Autopsy Specimens Reveals Significantly Deregulated Inflammatory Pathways and SFTPC Impaired Transcription

The transcriptomic profiling of lung damage associated with SARS-CoV-2 infection may lead to the development of effective therapies to prevent COVID-19-related deaths. We selected a series of 21 autoptic lung samples, 14 of which had positive nasopharyngeal swabs for SARS-CoV-2 and a clinical diagnosis of COVID-19-related death; their pulmonary viral load was quantified with a specific probe for SARS-CoV-2. The remaining seven cases had no documented respiratory disease and were used as controls. RNA from formalin-fixed paraffin-embedded (FFPE) tissue samples was extracted to perform gene expression profiling by means of targeted (Nanostring) and comprehensive RNA-Seq. Two differential expression designs were carried out leading to relevant results in terms of deregulation. SARS-CoV-2 positive specimens presented a significant overexpression in genes of the type I interferon signaling pathway (IFIT1, OAS1, ISG15 and RSAD2), complement activation (C2 and CFB), macrophage polarization (PKM, SIGLEC1, CD163 and MS4A4A) and Cathepsin C (CTSC). CD163, Siglec-1 and Cathepsin C overexpression was validated by immunohistochemistry. SFTPC, the encoding gene for pulmonary-associated surfactant protein C, emerged as a key identifier of COVID-19 patients with high viral load. This study successfully recognized SARS-CoV-2 specific immune signatures in lung samples and highlighted new potential therapeutic targets. A better understanding of the immunopathogenic mechanisms of SARS-CoV-2 induced lung damage is required to develop effective individualized pharmacological strategies.

Metachronous colorectal cancer have a similar microsatellite instability frequency but a lower infiltration of lymphomononuclear cells than primary lesions

BACKGROUND

An increased risk of metachronous colorectal cancer is usually associated with microsatellite instability occurring in Lynch syndrome. However, not all patients with metachronous colorectal cancer have microsatellite instability. The density of tumor-infiltrating lymphocytes is an independent predictor of outcome in patients with colorectal cancer, and a fascinating hypothesis is that they can be involved in the onset of metachronous colorectal cancer. The aim of this study was to analyze the tumor microenvironment and tumor mutation frequency in sporadic and metachronous colorectal cancer.

METHODS

The clinical and pathological records of a series of consecutive colorectal cancer patients who were operated on from 2015 to 2019 were retrieved for this retrospective study. We defined metachronous colorectal cancer as a second colorectal cancer that appeared at least 1 year after the primary one, and sporadic colorectal cancer as those that did not have a metachronous colorectal cancer. Histology for the infiltration of intratumoral lymphomononuclear cells, immunohistochemistry for MLH1, PMS2, MSH2, and MSH6, and mutational analysis of BRAF, KRAS, and NRAS were all performed. Sporadic colorectal cancer and metachronous colorectal cancer were compared. Nonparametric tests were used for small sample size comparison.

RESULTS

In the study, 238 patients were operated on for colorectal cancer at the General Surgery Unit of the Azienda Ospedaliera di Padova from 2015 to 2019. We identified 26 patients with metachronous colorectal cancer, and only 3 of them had had adjuvant therapy after the primary colorectal cancer. No difference was observed in terms of cancer stage between metachronous and sporadic colorectal cancer. Mismatch repair gene deficiencies and microsatellite instability frequency was similar in metachronous colorectal cancer and in sporadic colorectal cancer (P = .77). Likewise, the mutation frequency of BRAF and KRAs was similar in the 2 groups (P = .75 and P = .21, respectively). To the contrary, the absence of infiltration of lymphomononuclear cells within the tumor (P = .004) in patients with metachronous colorectal cancer was more frequent and they tended to have a higher frequency of NRAS mutation (P = .06).

CONCLUSION

Our study showed that, rather unexpectedly, microsatellite instability frequency was similar in metachronous and sporadic colorectal cancer. Moreover, our data suggest that an altered immune microenvironment may be a crucial factor, permitting the occurrence of metachronous colorectal cancer. In fact, the absence of lymphomononuclear cells can be the substrate for a weak immune response to cancer neoantigens, opening the way to a second primary colorectal cancer.

Intra-Articular Tumors

The intra-articular space is a relatively rare site of occurrence of neoplastic diseases. The 2 distinct groups of clinicopathologic entities that exhibit an almost exclusive tropism for the joints are represented by synovial chondromatosis and tenosynovial giant cell tumors (TGCT). Synovial chondromatosis is a locally aggressive chondrogenic neoplasm that very rarely can show malignant behavior. TGCT occur in 2 main variants, the localized variant and the more locally aggressive diffuse type. Malignant TCGT is exceedingly rare and is characterized by significant rates of both local recurrence and metastatic spread.

Association of CLDN18 Protein Expression with Clinicopathological Features and Prognosis in Advanced Gastric and Gastroesophageal Junction Adenocarcinomas

The tight junction protein claudin-18 (CLDN18), is often expressed in various cancer types including gastric (GC) and gastroesophageal adenocarcinomas (GECs). In the last years, the isoform CLDN18.2 emerged as a potential drug target in metastatic GCs, leading to the development of monoclonal antibodies against this protein. CLDN18.2 is the dominant isoform of CLDN18 in normal gastric and gastric cancer tissues. In this work, we evaluated the immunohistochemical (IHC) profile of CLDN18 and its correlation with clinical and histopathological features including p53, E-cadherin, MSH2, MSH6, MLH1, PMS2, HER2, EBER and PD-L1 combined positive score, in a large real-world and mono-institutional series of advanced GCs (n = 280) and GECs (n = 70). The association of IHC results with survival outcomes was also investigated. High membranous CLDN18 expression (2+ and 3+ intensity ≥75%) was found in 117/350 (33.4%) samples analyzed. CLDN18 expression correlated with age <70 (p = 0.0035), positive EBV status (p = 0.002), high stage (III, IV) at diagnosis (p = 0.003), peritoneal involvement (p < 0.001) and lower incidence of liver metastases (p = 0.013). CLDN18 did not correlate with overall survival. The predictive value of response of CLDN18 to targeted agents is under investigation in several clinical trials and further studies will be needed to select patients who could benefit from these therapies.

Mesenchymal tumours of the gastrointestinal tract

Mesenchymal tumours represent a heterogenous group of neoplasms encopassing benign, intermediate malignancy, and malignant entities. Sarcomas account for approximately 1% of human malignancies. In consideration of their rarity as well as of intrinsic complexity, diagnostic accuracy represents a major challenge. Traditionally, mesenchymal tumours are regarded as lesions the occurrence of which is mostly limited to somatic soft tissues. However, the occurrence of soft tissue tumours at visceral sites represent a well recognized event, and the GI-tract ranks among the most frequently involved visceral location. There exist entities such as gastrointestinal stromal tumours (GIST) and malignant gastointestinal neuroectodermal tumors that exhibit exquisite tropism for the GI-tract. This review will focus also on other relevant clinico-pathologic entities in which occurrence at visceral location is not at all negligible.

Feasibility of multiple immunoexpression assay for immune tumor micrornvironment (I-TME) on matched metastatic and primary renal cell carcinoma (RCC) for patient prognostication and predictiveness to immunotherapy (preliminary analyses of the Meet URO 18 study)

e16545

Background: The Meet-URO 18 study is ongoing to assess the prognostic role of I-TME in advanced RCC patients treated with ≥second line nivolumab divided into two cohorts according to clinical benefit [progression-free survival ≥ 12 and ≤ 3 months]. We primarily assessed the feasibility of multiple antibody testing related to I-TME on matched metastases and primary tumor. Methods: Immunohistochemical analyses were used for the TME assessment of T-lineage (CD3, CD4, CD8), FOXP-3, granulocytes (CD15), macrophage-lineage (CD68), natural killer (NK)-cells (CD56), tumor cells (TCs) (CD56), B-lineage (CD20) and phosphorylated mTOR (phmTOR). TCs were quantitatively assessed for CD15, CD56 and phmTOR positivity. For T-, B- and CD68 cells within TC nests, the number of immunoreactive cells were counted with a microscopic field of x200 (0.933 mm2). Results: Overall, 42 tumor tissue samples (primary tumors, metastases) were available and for 17 patients both metastatic and primary tumor tissues were assessable for matched analyses. Among these patients, 12 had clear cell, 1 papillary and 4 mucinous tubular and spindle cell histotype according to WHO 2016 classification. Intratumoral T/CD8 cells ranged from 32 to >400 spots (mean 240; >400 in 7 samples) and intratumoral T/CD4 cells from 4 to >400 spots (mean 168; >400 in 5 samples). Nine samples showed absence of phmTOR expression, while 8 ranged from 10% to 90% of positive TCs. We did not observe countable NK-cells, whereas CD56 was visible in 5 samples (mean 55% of positive TCs). Intratumoral CD68 cells ranged from 34 to >400 spots (mean 175, >400 in 3 patients). Agreement of CD15 method of reporting granulocytic presence was high, thus only CD15 neoplastic expression was reported and ranged from 12% to 55% (mean 30%) in 15 patients. TME multiple analysis resulted equally clustered in 8 patients (<20% variability of single immuno-test) whereas the remaining 9 patients showed significant differences as percentage of immuno-tissue expression in at least one of the 5 immuno-indicators (T/CD8-CD4, C15, CD68, CD56, phmTOR). The remaining 8 samples of patients without matched analyses were used to test the feasibility of multiple analyses; among all antibodies exclusion of the CD20 and FOXP-3 final evaluation was needed, due to technical standardization. According to the 5 immuno-indicators, double-triple positive or penta-positive TME indicators may be identified and graded. Conclusions: Providing multiple immunoexpression platforms on a single specimen may be used as routine workflow. Profiling I-TME, especially CD56, CD15 on TCs and CD68 cells and phmTOR, deserves investigation with extensive control groups. A validation cohort will be tested at tissue level and in correlation with peripheral blood markers.

Circulating prostaglandin E2: a novel potential prognostic biomarker in patients with hepatocellular carcinoma

We aimed to explore the activation of monoacylglycerol lipase (MAGL)/cyclooxygenase-2 (COX-2)/prostaglandin E₂ (PGE2) axis in hepatocellular carcinoma (HCC), evaluating circulating PGE2 as prognostic biomarker in HCC patients. PGE2 levels were measured in blood samples from 24 cirrhotics, and 34 HCC patients were consecutively collected between January 2016 and December 2017. In a subgroup of patients, tissue expression of MAGL mRNA and immunohistochemistry for MAGL and COX-2 were obtained. Despite tumor tissues showing overexpression of MAGL mRNA and higher levels of both MAGL and COX-2 at immunohistochemistry, PGE2 levels were not significantly different in HCC and cirrhotics. HCC patients with circulating PGE2 levels > 14 pg/mL had a significantly shorter overall survival (19.4 vs. 49.9 months; p = 0.03), the finding being confirmed by the multivariate analysis (HR 3.37 [95% CI 1.00-11.60]; p = 0.05). The MAGL/COX-2/PGE2 axis is activated in HCC, and circulating PGE2 proved to be a potential prognostic biomarker.

MicroRNAs as Predictive Biomarkers of Resistance to Targeted Therapies in Gastrointestinal Tumors

The advent of precision therapies against specific gene alterations characterizing different neoplasms is revolutionizing the oncology field, opening novel treatment scenarios. However, the onset of resistance mechanisms put in place by the tumor is increasingly emerging, making the use of these drugs ineffective over time. Therefore, the search for indicators that can monitor the development of resistance mechanisms and above all ways to overcome it, is increasingly important. In this scenario, microRNAs are ideal candidate biomarkers, being crucial post-transcriptional regulators of gene expression with a well-known role in mediating mechanisms of drug resistance. Moreover, as microRNAs are stable molecules, easily detectable in tissues and biofluids, they are the ideal candidate biomarker to identify patients with primary resistance to a specific targeted therapy and those who have developed acquired resistance. The aim of this review is to summarize the major studies that have investigated the role of microRNAs as mediators of resistance to targeted therapies currently in use in gastro-intestinal neoplasms, namely anti-EGFR, anti-HER2 and anti-VEGF antibodies, small-molecule tyrosine kinase inhibitors and immune checkpoint inhibitors. For every microRNA and microRNA signature analyzed, the putative mechanisms underlying drug resistance were outlined and the potential to be translated in clinical practice was evaluated.

Treatment personalization in gastrointestinal neuroendocrine tumors

OPINION STATEMENT

The clinical scenario of gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) is continuously changing due to significant improvements in the definition of their molecular landscapes and the introduction of innovative therapeutic approaches. Many efforts are currently employed in the integration of the genetics/epigenetics and clinical information. This is leading to an improvement of tumor classification, prognostic stratification and ameliorating the management of patients based on a personalized approach.

The impact of recent next generation sequencing and the need for a new classification in gastric cancer

The phenotypical and molecular heterogeneity of gastric cancer has hampered the introduction in clinical practice of a unifying classification of the disease. However, as next generation sequencing (NGS) technologies enhanced the comprehension of the molecular landscape of gastric cancer, novel molecular classification systems have been proposed, allowing the dissection of molecular tumor heterogeneity and paving the way for the development of new targeted therapies. Moreover, the use of NGS analyses in the molecular profiling of formalin-fixed paraffin-embedded (FFPE) specimens will improve patient selection for the enrolment in novel clinical trials. In conclusion, the application of NGS in precision oncology will revolutionize the diagnosis and clinical management in gastric cancer patients.

Esophageal squamous cell carcinoma metachronous to head and neck cancers

BACKGROUND

In some HNSCC patients, a metachronous ESCC may develop. No information is available on the HNSCC-associated ESCCs microenvironment and etiology.

METHODS

Among 134 ESCCs surgically treated between 2009 and 2015, a series of 6 HNSCC-associated ESCCs was collected. A series of 12 sex-, age- and stage-matched ESCCs with no previous oncological medical history was selected for comparison. Histologic assessment of intratumoral inflammatory infiltration and immunohistochemistry for CD4, CD8, CD80, PD1, PD-L1 and p53 were performed. HPV detection/genotyping was assessed by PCR single step and reverse line blot.

RESULTS

HPV DNA was negative in all the HNSCC-associated ESCCs. In comparison to non-HNSCC-associated carcinomas, the 6 cases presented a lower lymphomonocytic infiltration, which also corresponded to a lower prevalence of CD4 + T cell infiltration and, 5/6 cases presented a PD-L1 CPS ≥ 1. All the HNSCC-associated ESCCs resulted positive for p53 immunostaining in ≥50 % of cancer cells.

CONCLUSION

Our study suggests that HPV infection is not an etiological factor associated to ESCC after HNSCC. On the other hand, p53 overexpression is a common finding. Moreover, our data suggest that an altered immune microenvironment, conditioned by a dysregulation in lymphomonocytic infiltration, may be a crucial factor allowing the occurrence of a metachronous ESCC.

The Immunopathological and Histological Landscape of COVID-19-Mediated Lung Injury

A complete understanding of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) physiopathology and related histopathologic lesions is necessary to improve treatment and outcome of coronavirus disease 2019 (COVID-19) patients. Many studies have focused on autopsy findings in COVID-19-related deaths to try and define any possible specific pattern. Histopathologic alterations are principally found within lungs and blood vessels, and these abnormalities also seem to have the highest clinical impact. Nevertheless, many of the morphological data collected so far are non-specific, fickle, and possibly associated with other co-existing factors. The aim of this minireview is to describe the main histopathological features related to COVID-19 and the mechanism known as "cytokine storm".

The Pathologic and Molecular Landscape of Esophageal Squamous Cell Carcinogenesis

Esophageal squamous cell carcinoma represents the most common histotype of epithelial neoplasm occurring within esophageal mucosa worldwide. Despite the comprehensive molecular characterization of this entity, to date no significant targeted therapy has been introduced into clinical practice. In this review, we describe the molecular landscape of esophageal squamous cell carcinoma based on the most recent literature. Moreover, we focus on other rare variants and on the relationship with head and neck squamous cell carcinomas.

Histopathological landscape of rare oesophageal neoplasms

The landscape of neoplastic pathology of the oesophagus is dominated by malignancies of epithelial origin, in particular by oesophageal adenocarcinoma and oesophageal squamous cell carcinoma. However, several other histopathological variants can be distinguished, some associated with peculiar histopathological profiles and prognostic behaviours and frequently underrecognized in clinical practice. The aim of this review is to provide a comprehensive characterization of the main morphological and clinical features of these rare variants of oesophageal neoplastic lesions.