Claudin-18 expression in oesophagogastric adenocarcinomas: a tissue microarray study of 523 molecularly profiled cases

BACKGROUND

Claudin-18 (CLDN18) is a highly specific tight junction protein of the gastric mucosa. An isoform of CLDN18, the Claudin 18.2, has recently emerged as an innovative drug target for metastatic gastric cancer.

METHODS

We investigated the immunohistochemical profile of CLDN18, p53, p16, E-cadherin, MSH2, MSH6, MLH1, PSM2, HER2, and PDL-1 in a large series of 523 primary gastric carcinomas (GCs; n = 408) and gastro-oesophageal carcinomas (GECs; n = 115) and 135 matched and synchronous nodal metastases. The status of HER2 and EBER by means of chromogenic in situ hybridisation (CISH) was also evaluated.

RESULTS

High membranous CLDN18 expression was present in 150/510 (29.4%) primary cases and in 45/132 (34.1%) metastases. An abnormal expression (i.e. nuclear and/or cytoplasmic) was observed in 115 (22.5%) primary cases and in 33 (25.0%) metastases. A 38.8% of the cases showed significant CLDN18 intratumoural variability among the different tissue microarray cores obtained from the same tumour. Positive membrane CLDN18 expression was statistically associated with non-antral GCs (p = 0.016), Lauren diffuse type (p = 0.009), and with EBV-associated cancers (p < 0.001).

CONCLUSIONS

CLDN18 is frequently expressed in gastric and gastro-oesophageal cancers; further studies should investigate the prognostic significance of CLDN18 heterogeneity in order to implement its test into clinical practice.

Molecular characterization of "sessile serrated" adenoma to carcinoma transition in six early colorectal cancers

Colorectal cancer (CRC) is a heterogeneous group of diseases both from the morphological and molecular point of view. The sessile serrated adenoma/polyp (SSA/P) has been proposed as the precursor lesion of CRCs characterized by CpG island methylator phenotype (CIMP), DNA mismatch repair (MMR) system deficiency, and BRAF gene mutations. However, no study so far investigated the molecular landscape of "sessile serrated" adenoma to carcinoma transition in early CRCs. Six formalin-fixed paraffin-embedded CRCs developed within SSA/P were profiled for the immunohistochemical expression of MMR proteins (MLH1, MSH2, MSH6, PMS2, and Ep-CAM), p16, and β-catenin. DNA was extracted from the two components of each sample, after microdissection, and characterized for CIMP status and by applying a custom hotspot multigene mutational profiling of 164 hotspot regions of eleven CRC-associated genes (AKT1, APC, BRAF, CTNNB1, KIT, KRAS, NRAS, PDGFRA, PIK3CA, PTEN, and TP53). Five out of the six CRCs shared the same molecular profile (i.e. CIMP positive, MSI status, and BRAF mutation) with their SSA/P components. One out of five CRCs was also APC mutated, whereas another one showed an additional TP53 mutation. The remaining case was CIMP negative and MMR proficient in both the components, harbored a BRAF mutation in the SSA/P counterpart, whereas the CRC one was APC and TP53 mutated and showed p16 and β-catenin dysregulation. This study provides the molecular evidence that SSA/P, even without cytological dysplasia, is a precursor lesion of CRC and that conventional CRC might arise from mixed polyp.

MiR-122 Targets SerpinB3 and Is Involved in Sorafenib Resistance in Hepatocellular Carcinoma

The only first-line treatment approved for advanced hepatocellular carcinoma (HCC) is sorafenib. Since many patients experience drug resistance, the discovery of more effective therapeutic strategies represents an unmet clinical need. MicroRNA (MiR)-122 is downregulated in most HCCs, while oncogenic SerpinB3 is upregulated. Here, we assessed the relationship between miR-122 and SerpinB3 and their influence on cell phenotype and sorafenib resistance in HCC. A bioinformatics analysis identified SerpinB3 among hypothetical miR-122 targets. In SerpinB3-overexpressing HepG2 cells, miR-122 transfection decreased SerpinB3 mRNA and protein levels, whereas miR-122 inhibition increased SerpinB3 expression. Luciferase assay demonstrated the interaction between miR-122 and SerpinB3 mRNA. In an HCC rat model, high miR-122 levels were associated with negative SerpinB3 expression, while low miR-122 levels correlated with SerpinB3 positivity. A negative correlation between miR-122 and SerpinB3 or stem cell markers was found in HCC patients. Anti-miR-122 transfection increased cell viability in sorafenib-treated Huh-7 cells, while miR-122 overexpression increased sorafenib sensitivity in treated cells, but not in those overexpressing SerpinB3. In conclusion, we demonstrated that miR-122 targets SerpinB3, and its low levels are associated with SerpinB3 positivity and a stem-like phenotype in HCC. MiR-122 replacement therapy in combination with sorafenib deserves attention as a possible therapeutic strategy in SerpinB3-negative HCCs.

Colonic Ewing Sarcoma/PNET associated with liver metastases: A systematic review and case report

Ewing Sarcoma is a highly lethal undifferentiated tumor of bone. ES is a small round cell tumor with etiological and characteristic chromosomal translocations between TET/FET (TLS/FUS, EWSR1, and TAF15) and ETS (E26 transformation-specific) family genes. Generally, therapeutic approach for metastatic Ewing Sarcoma includes both local (surgery and radiotherapy) and systemic (chemotherapy) disease control with an overall cure rate of 20%. For extra-osseous tumors, the most common primary sites of disease are trunk, extremities, head and neck, retroperitoneum. Among other sites, Ewing Sarcoma/PNET may also rarely arise in colon and rectum. Even if colonic Ewing Sarcoma/PNET have been previously reported in 5 cases, none of those reports came from right side of the colon. In this article, we report the first case of right-sided Ewing Sarcoma with synchronous liver metastases completely responding to first line chemotherapy. Furthermore, we provide a systematic qualitative review of the current literature on adult colorectal Ewing Sarcoma using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

LONG-NONCODING RNAs in gastroesophageal cancers

Despite continuing improvements in multimodal therapies, gastro-esophageal malignances remain widely prevalent in the population and is characterized by poor overall and disease-free survival rates. Due to the lack of understanding about the pathogenesis and absence of reliable markers, gastro-esophageal cancers are associated with delayed diagnosis. The increasing understanding about cancer's molecular landscape in the recent years, offers the possibility of identifying 'targetable' molecular events and in particular facilitates novel treatment strategies and development of biomarkers for early stage diagnosis. At least 98% of our genome is actively transcribed into non-coding RNAs encompassing long non-coding RNAs (lncRNAs) constituted of transcripts longer than 200 nucleotides with no protein-coding capacity. Many studies have demonstrated that lncRNAs are functional genomic elements playing pivotal roles in main oncogenic processes. LncRNA can act at multiple levels developing a complex molecular network that can modulate directly or indirectly the expression of genes involved in tumorigenesis. In this review, we focus on lncRNAs as emerging players in gastro-esophageal carcinogenesis and critically assess their potential as reliable noninvasive biomarkers and in next generation targeted therapies.

Human papillomavirus infection is not involved in esophageal verrucous carcinoma

Verrucous carcinoma of the esophagus (VCE) is a rare variant of squamous cell cancer, with a puzzling clinical, etiological, and molecular profile. The etiological involvement of human papillomavirus (HPV) in the cancer's natural history is controversial. This study considers 9 cases of VCE, focusing on patients' clinical history before surgery, histologic phenotype, immunophenotype (epidermal growth factor receptor [EGFR], E-cadherin, cyclin D1, p16, and p53 expression), HPV infection, and TP53 gene mutational status (exons 5-8). Using 3 different molecular test methods, not one of these cases of VCE featured HPV infection. The only case with synchronous nodal metastasis was characterized by a TP53 missense point mutation in association with high EGFR and low E-cadherin expression levels. In conclusion, HPV infection is probably not involved with VCE, while TP53 gene mutation, EGFR overexpression, and E-cadherin loss might fuel the tumor's proliferation and lend it a metastatic potential.

Assessment of intratumor immune-microenvironment in colorectal cancers with extranodal extension of nodal metastases

BACKGROUND

No data is available on the molecular background of the extra-nodal extension (ENE) of lymph node metastasis (LN) in colorectal cancer (CRC).

METHODS

A series of 22 ENE-positive CRCs was considered and three samples per case were selected (the primary CRC, an ENE-negative and an ENE-positive metastatic LN). Samples (n = 66) were analysed by immunohistochemistry for PD-L1, CD4, CD8, CD68 and CD80. Fifteen out of twenty-two cases were further profiled through a hotspot multigene mutational custom panel, including 164 hotspot regions of AKT1, APC, BRAF, CTNNB1, KIT, KRAS, NRAS, PDGFRA, PIK3CA, PTEN and TP53 genes.

RESULTS

A significantly higher percentage of CD4-, CD8- and CD68-positive cells was observed at the invasive front of both CRCs and in ENE in contrast with what observed at the core of both CRCs and their matched nodal metastases. ENE was also characterized by a significantly higher number of CD80-positive cells. No significant difference was observed in PD-L1 distribution among the different specimens. Fourteen out of 15 CRCs (93%) showed at least a driver mutation. The most frequently mutated gene was TP53 (n = 8 tumors), followed by APC (n = 6), BRAF (n = 4), KRAS, NRAS and PIK3CA (n = 2). In 11 out of 15 CRCs (73%) the mutational profiling of the primary tumor was consistent with what obtained from the two matched LNs.

CONCLUSIONS

A heterogeneous intratumor immune-microenvironment has been observed in ENE-positive CRCs, which are characterized by an increased leukocytic infiltration at the ENE invasive front.

Molecular Diagnostics in Pathology: Time for a Next-Generation Pathologist?

Context.—

Comprehensive molecular investigations of mainstream carcinogenic processes have led to the use of effective molecular targeted agents in most cases of solid tumors in clinical settings.

Objective.—

To update readers regarding the evolving role of the pathologist in the therapeutic decision-making process and the introduction of next-generation technologies into pathology practice.

Data Sources.—

Current literature on the topic, primarily sourced from the PubMed (National Center for Biotechnology Information, Bethesda, Maryland) database, were reviewed.

Conclusions.—

Adequate evaluation of cytologic-based and tissue-based predictive diagnostic biomarkers largely depends on both proper pathologic characterization and customized processing of biospecimens. Moreover, increased requests for molecular testing have paralleled the recent, sharp decrease in tumor material to be analyzed—material that currently comprises cytology specimens or, at minimum, small biopsies in most cases of metastatic/advanced disease. Traditional diagnostic pathology has been completely revolutionized by the introduction of next-generation technologies, which provide multigene, targeted mutational profiling, even in the most complex of clinical cases. Combining traditional and molecular knowledge, pathologists integrate the morphological, clinical, and molecular dimensions of a disease, leading to a proper diagnosis and, therefore, the most-appropriate tailored therapy.

Noncoding RNAs as drivers of the phenotypic plasticity of oesophageal mucosa

The histological commitment of the lower oesophageal mucosa largely depends on a complex molecular landscape. After extended inflammatory insult due to gastroesophageal reflux disease, squamous oesophageal mucosa may differentiate into columnar metaplastic mucosa. In this setting, the presence of intestinal metaplasia is considered the starting point of Barrett’s carcinogenetic cascade. Aside from secondary prevention strategies for Barrett’s mucosa (BM) patients, there are multiple endoscopic ablative therapies available for BM eradication and for the replacement of metaplastic epithelia with a neosquamous mucosa. However, BM frequently recurs in a few years, which supports the notable phenotypic plasticity of the oesophageal mucosa. In recent years, several reports pinpointed a class of small noncoding RNAs, the microRNAs (miRNAs), as principal effectors and regulators of oesophageal mucosa metaplastic (and neoplastic) transformation. Because of miRNAs notable stability in fixed archival diagnostic specimens, expression profiling of miRNAs represent an innovative diagnostic, prognostic and predictive tool in the stratification of phenotypic alterations in the oesophageal mucosa.

Fhit down-regulation is an early event in pancreatic carcinogenesis

Aberrant Fhit expression characterizes a large proportion of primary pancreatic ductal adenocarcinomas (PDACs), but fragmentary information is available on Fhit expression during the phenotypic changes of pancreatic ductal epithelium during multistep transformation. We assessed Fhit expression by immunohistochemistry in two different multistep pancreatic carcinogenic processes: pancreatic intraepithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasia (IPMN). We considered 105 surgically treated PDACs/IPMNs and selected 30 samples of non-neoplastic pancreatic parenchyma, 50 PanIN lesions, 30 IPMNs, 15 IPMNs with associated invasive carcinoma, and 60 adenocarcinomas. Normal pancreatic ducts and surrounding acinar cells consistently showed moderate to strong Fhit immunoreactivity. Significant down-regulation of Fhit expression was observed in association with increasing severity of dysplastia/neoplastia in both carcinogenic processes. This was further confirmed by studying multiple lesions obtained from the same surgical specimen. Of 60 PDACs, only 14 showed Fhit expression comparable to normal pancreatic ductal epithelium, while the remainder (77%) showed clearly negative or reduced Fhit expression. This study demonstrates that Fhit down-regulation is an early event in both multistep carcinogenic processes leading to PDAC.

Insulin promotes HER2 signaling activation during Barrett's Esophagus carcinogenesis

BACKGROUND

Insulin-resistance and hyperinsulinemia could have a role in the growing incidence of esophageal adenocarcinoma (EAC) and its pre-cancerous lesion Barrett's Esophagus (BE). HER2 activation has also a pivotal role in EAC carcinogenesis but no data correlate these two phenomena in this disease context.

AIMS

To investigate the role of hyperinsulinemia in BE-dysplasia-adenocarcinoma sequence and the possible relationship between insulin-mediated and HER2 signaling in EAC development.

METHODS

Serum insulin, C-peptide, IGF1, glucagon, IL-6, TNF-alpha, leptin, adiponectin and Insulin-Resistance-index were analyzed in 19 patients with gastro-esophageal reflux disease, 51 with BE, 24 with dysplastic-BE and 14 with EAC. Insulin/IGF1/HER2 pathways were analyzed in esophageal biopsies using Luminex^® Technology. Insulin effect was also evaluated in EAC-derived OE19 cells. Data were analyzed by Fisher's exact test, Kruskal-Wallis test, Mann-Whitney U-test, Cuzick's test and Spearman correlation coefficient calculation.

RESULTS

Insulin-Resistance-index, insulin and C-peptide levels increased along with disease progression (p=0.019, p=0.002, p<0.0001, respectively) and correlated with HER2 expression and with downstream mediators phospho-Akt and phospho-mTOR in esophageal tissue. In vitro, insulin was also able to induce cell proliferation through HER2 activation.

CONCLUSIONS

Our data pinpoint a possible role of hyperinsulinemia in the Barrett's Esophagus metaplasia-dysplasia-adenocarcinoma sequence through HER2 activation in esophageal epithelial cells.

Adenosquamous gallbladder carcinoma: Multigene hotspot mutational profiling reveals a monoclonal origin of the two components

Adenosquamous carcinoma (ASC) of the gallbladder is a rare malignant tumor that is characterized by a coexisting of glandular and squamous components. In a case of ASC, we performed hotspot multigene mutational profiling of 164 hotspot regions of eleven cancer-associated genes (AKT1, APC, BRAF, CTNNB1, KIT, KRAS, NRAS, PDGFRA, PIK3CA, PTEN and TP53) in the two microdissected components. Both tumor phenotypes resulted characterized by a p.E542K point mutation in the PIK3CA gene, whereas adenocarcinoma component revealed also a TP53 Q331* homozygous stop mutation. Of note, coexisting high-grade dysplastic epithelium was characterized by a mixed cell population, with an upper part featuring a glandular differentiation and a basal layer of p63 positive (squamous committed) cells. Overall these data provide evidence of an early squamous differentiation of the lesion with a common genetic landscape of the two components.

Tumor budding as a risk factor for nodal metastasis in pT1 colorectal cancers: a meta-analysis

Worldwide, colorectal cancer (CRC) screening programs have significantly increased the detection of submucosal (pT1) adenocarcinoma. Completion surgery may be indicated after endoscopic excision of these potentially metastasizing early cancers. However, the postsurgical prevalence of nodal implants does not exceed 15%, leading to questions concerning the clinical appropriateness of any post-endoscopy surgery. Eastern scientific societies (Japanese Society for Cancer of the Colon-Rectum, in particular) include tumor budding (TB), defined as the presence of isolated single cancer cells or clusters of fewer than 5 cancer cells at the tumor invasive front, among the variables that must be included in histologic reports. In Western countries, however, no authoritative endorsements recommend the inclusion of TB in the histology report because of the heterogeneity of definitions and measurement methods as well as its apparent poor reproducibility. To assess the prognostic value of TB in pT1 CRCs, this meta-analysis evaluated 41 studies involving a total of 10137 patients. We observed a strong association between the presence of TB and risk of nodal metastasis in pT1 CRC. In comparing TB-positive (684/2401; 28.5%) versus TB-negative (557/7736; 7.2%) patients, the prevalence of nodal disease resulted in an odds ratio value of 6.44 (95% confidence interval, 5.26-7.87; P<.0001; I² = 30%). This increased risk of regional nodal metastasis was further confirmed after accounting for potential confounders. These results support the priority of histologically reporting TB in any endoscopically removed pT1 CRC to direct more appropriate patient management.

Autoimmune gastritis: Pathologist’s viewpoint

Western countries are seeing a constant decline in the incidence of Helicobacter pylori-associated gastritis, coupled with a rising epidemiological and clinical impact of autoimmune gastritis. This latter gastropathy is due to autoimmune aggression targeting parietal cells through a complex interaction of auto-antibodies against the parietal cell proton pump and intrinsic factor, and sensitized T cells. Given the specific target of this aggression, autoimmune gastritis is typically restricted to the gastric corpus-fundus mucosa. In advanced cases, the oxyntic epithelia are replaced by atrophic (and metaplastic) mucosa, creating the phenotypic background in which both gastric neuroendocrine tumors and (intestinal-type) adenocarcinomas may develop. Despite improvements in our understanding of the phenotypic changes or cascades occurring in this autoimmune setting, no reliable biomarkers are available for identifying patients at higher risk of developing a gastric neoplasm. The standardization of autoimmune gastritis histology reports and classifications in diagnostic practice is a prerequisite for implementing definitive secondary prevention strategies based on multidisciplinary diagnostic approaches integrating endoscopy, serology, histology and molecular profiling.

From Barrett metaplasia to esophageal adenocarcinoma: the molecular background

The molecular landscape of Barrett's esophagus and Barrett-related neoplastic lesions is still far from being completely elucidated. Both in vitro and in vivo studies pinpointed the pathogenetic role of different morphogenic pathways (the para-homeobox, the Notch and the Sonic Hedgehog families in particular) implicated in the acquisition of the metaplastic phenotype of the esophageal mucosa. On the other hand, the most common genetic alterations observed during Barrett's carcinogenesis include disorders of major regulators of the cell cycle, as well as deregulation of the TGF-β/Smad and receptor tyrosine kinases signalling pathways. Recent comprehensive mutational profiling studies identified that the inactivation of the TP53 and of the SMAD4 tumour suppressor genes occurred in a stage-specific manner, confined to (high grade) dysplastic and neoplastic lesions, respectively. The next step will be the correlation of these findings into multidisciplinary diagnostic approaches integrating endoscopy, histology, molecular profiling and liquid biopsies. This will allow the introduction of innovative strategies for secondary prevention of esophageal adenocarcinoma based on biological rationales, and the implementation of potential novel therapeutic targets.

From Barrett metaplasia to esophageal adenocarcinoma: the molecular background

The molecular landscape of Barrett's esophagus and Barrett-related neoplastic lesions is still far from being completely elucidated. Both in vitro and in vivo studies pinpointed the pathogenetic role of different morphogenic pathways (the para-homeobox, the Notch and the Sonic Hedgehog families in particular) implicated in the acquisition of the metaplastic phenotype of the esophageal mucosa. On the other hand, the most common genetic alterations observed during Barrett's carcinogenesis include disorders of major regulators of the cell cycle, as well as deregulation of the TGF-β/Smad and receptor tyrosine kinases signalling pathways. Recent comprehensive mutational profiling studies identified that the inactivation of the TP53 and of the SMAD4 tumour suppressor genes occurred in a stage-specific manner, confined to (high grade) dysplastic and neoplastic lesions, respectively. The next step will be the correlation of these findings into multidisciplinary diagnostic approaches integrating endoscopy, histology, molecular profiling and liquid biopsies. This will allow the introduction of innovative strategies for secondary prevention of esophageal adenocarcinoma based on biological rationales, and the implementation of potential novel therapeutic targets.

MicroRNA expression profiling of male breast cancer

Introduction

MicroRNAs (miRNAs) are a class of small noncoding RNAs that control gene expression by targeting mRNAs and triggering either translation repression or RNA degradation. Their aberrant expression may be involved in human diseases, including cancer. To test the hypothesis that there is a specific miRNA expression signature which characterizes male breast cancers, we performed miRNA microarray analysis in a series of male breast cancers and compared them with cases of male gynecomastia and female breast cancers.

Methods

Paraffin blocks were obtained at the Department of Pathology of Thomas Jefferson University from 28 male patients including 23 breast cancers and five cases of male gynecomastia, and from 10 female ductal breast carcinomas. The RNA harvested was hybridized to miRNA microarrays (~1,100 miRNA probes, including 326 human and 249 mouse miRNA genes, spotted in duplicate). To further support the microarray data, an immunohistochemical analysis for two specific miRNA gene targets (HOXD10 and VEGF) was performed in a small series of male breast carcinoma and gynecomastia samples.

Results

We identified a male breast cancer miRNA signature composed of a large portion of underexpressed miRNAs. In particular, 17 miRNAs with increased expression and 26 miRNAs with decreased expression were identified in male breast cancer compared with gynecomastia. Among these miRNAs, some had well-characterized cancer development association and some showed a deregulation in cancer specimens similar to the one previously observed in the published signatures of female breast cancer. Comparing male with female breast cancer miRNA expression signatures, 17 significantly deregulated miRNAs were observed (four overexpressed and 13 underexpressed in male breast cancers). The HOXD10 and VEGF gene immunohistochemical expression significantly follows the corresponding miRNA deregulation.

Conclusions

Our results suggest that specific miRNAs may be directly involved in male breast cancer development and that they may represent a novel diagnostic tool in the characterization of specific cancer gene targets.