Differentiating the undifferentiated: immunohistochemical profile of medullary carcinoma of the colon with an emphasis on intestinal differentiation

Medullary carcinomas of the nonampullary small intestine: association with coeliac disease, mismatch repair deficiency, PD-L1 expression, and favourable prognosis

AIM

Gastrointestinal medullary carcinoma is a rare histologic subtype of adenocarcinoma. As nonampullary small bowel medullary carcinomas (SB-MCs) are poorly characterized, we aimed to analyse their clinicopathologic and immunohistochemical features and to compare them with nonmedullary small bowel adenocarcinomas (NM-SBAs).

METHODS AND RESULTS

Surgically resected SBAs collected through the Small Bowel Cancer Italian Consortium were classified as SB-MCs (carcinomas with ≥50% of tumour fulfilling the typical histologic criteria of MC) or NM-SBAs. Immunohistochemistry for cytokeratin (CK)7, CK20, CDX2, programmed death-ligand 1 (PD-L1) and mismatch repair proteins was performed in both SB-MCs and NM-SBAs. SB-MCs were also tested for CK8/18, synaptophysin, SMARCB1, SMARCA2, SMARCA4, and ARID1A and for Epstein-Barr virus (EBV)-encoded RNAs by in-situ hybridization. MLH1 promoter methylation status was evaluated in MLH1-deficient cases. Eleven SB-MCs and 149 NM-SBAs were identified. One (9%) SB-MC was EBV-positive, while 10 (91%) harboured mismatch repair deficiency (dMMR). MLH1 promoter hypermethylation was found in all eight dMMR SB-MCs tested. Switch/sucrose nonfermentable deficiency was seen in two (18%) SB-MCs, both with isolated loss of ARID1A. Compared with NM-SBAs, SB-MCs exhibited an association with coeliac disease (P < 0.001), higher rates of dMMR (P < 0.001), and PD-L1 positivity by both tumour proportion score and combined positive score (P < 0.001 for both), and a lower rate of CK20 expression (P = 0.024). Survival analysis revealed a better prognosis of SB-MC patients compared to NM-SBA cases (P = 0.02).

CONCLUSION

SB-MCs represent a distinct histologic subtype, with peculiar features compared to NM-SBAs, including association with coeliac disease, dMMR, PD-L1 expression, and better prognosis.

Colorectal medullary carcinoma: a pathological subtype with intense immune response and potential to benefit from immune checkpoint inhibitors

INTRODUCTION

Different pathological types of colorectal cancer have distinguished immune landscape, and the efficacy of immunotherapy will be completely different. Colorectal medullary carcinoma, accounting for 2.2-3.2%, is characterized by massive lymphocyte infiltration. However, the attention to the immune characteristics of colorectal medullary carcinoma is insufficient.

AREA COVERED

We searched the literature about colorectal medullary carcinoma on PubMed through November 2023to investigate the hallmarks of colorectal medullary carcinoma's immune landscape, compare medullary carcinoma originating from different organs and provide theoretical evidence for precise treatment, including applying immunotherapy and BRAF inhibitors.

EXPERT OPINION

Colorectal medullary carcinoma is a pathological subtype with intense immune response, with six immune characteristics and has the potential to benefit from immunotherapy. Mismatch repair deficiency, ARID1A missing and BRAF V600E mutation often occurs. IFN-γ pathway is activated and PD-L1 expression is increased. Abundant lymphocyte infiltration performs tumor killing function. In addition, BRAF mutation plays an important role in the occurrence and development, and we can consider the combination of BRAF inhibitors and immunotherapy in patients with BRAF mutant. The exploration of colorectal medullary carcinoma will arouse researchers' attention to the correlation between pathological subtypes and immune response, and promote the process of precise immunotherapy.

Emerging and under-recognised patterns of colorectal carcinoma morphologies: a comprehensive review

While the overwhelming majority of colorectal carcinomas (CRC) are diagnosed as adenocarcinoma not otherwise specified, there are numerous under-recognised morphologic patterns of CRC. These patterns are recognised by the WHO, appear in reporting manuals for the American Joint Committee of Cancer, and/or are listed on synoptic reports, while many other variants have either fallen out of favour or are emerging as future bona fide patterns. Herein, we discuss 13 variants: serrated adenocarcinoma, micropapillary adenocarcinoma, medullary carcinoma, neuroendocrine carcinoma, mucinous adenocarcinoma, signet-ring cell carcinoma, adenosquamous carcinoma, adenoma-like adenocarcinoma, lymphoglandular complex-like CRC, carcinoma with sarcomatoid components, cribriform-comedo-type adenocarcinoma, undifferentiated carcinoma and low-grade tubuloglandular adenocarcinoma. The purpose of this review is to scrutinise these variants by assessing their clinical characteristics, morphologic cues, as well as pitfalls, and address their prognostic significance. Our analysis aims to bring clarity and updated understanding to these variants, offering valuable insights for pathologists. This contributes to more nuanced CRC diagnosis and treatment strategies, highlighting the importance of recognising a broad spectrum of morphologic patterns in CRC.

Risk factor analysis and nomogram development and verification for medullary carcinoma of the colon using SEER database

Medullary Carcinoma of the Colon (MCC) is a rare histological subtype of colon cancer, and there is currently no recognized optimal treatment plan for it, with its prognosis remaining unclear. The aim of this study is to analyze the independent prognostic factors for MCC patients and develop and validate nomograms to predict overall survival (OS). A total of 760 patients newly diagnosed with MCC from 2004 to 2020 were selected from the Surveillance, Epidemiology, and End Results (SEER) database. All patients were randomly allocated to a training group and a validation group in a 7:3 ratio. Univariate and multivariable Cox regression analyses were conducted to identify prognostic factors and construct nomograms. The nomogram prediction model was evaluated and validated using receiver operating characteristic (ROC) curves, calibration curves, and decision curve analysis (DCA). The study found that elderly women are more susceptible to MCC, and the ascending colon and cecum are the most common sites of involvement. MCC is poorly differentiated, with stages II and III being the most common. Surgery is the primary treatment for MCC. The prognosis for patients with stage IV MCC is poor, with a median survival time of only 10 months. Independent prognostic factors for MCC include age, N stage, M stage, surgery, chemotherapy, and tumor size. Among them, age < 75 years and completion of chemotherapy were protective factors for colon medullary carcinoma, while N2 (HR = 2.18, 95%CI 1.40-3.38), M1 (HR = 3.31, 95%CI 2.01-5.46), no surgery (HR = 27.94, 95%CI 3.69-211.75), and tumor diameter > 7 cm (HR = 1.66, 95%CI 1.20-2.30) were risk factors for colon medullary carcinoma. The results of ROC, AUC, calibration curves, and DCA demonstrate that the nomogram prediction model exhibits good predictive performance. We have updated the demographic characteristics of colon medullary carcinoma and identified age, N staging, M staging, surgery, chemotherapy and tumor size as independent prognostic factors for colon medullary carcinoma. Additionally, we have established nomograms for prognostic prediction. These nomograms can provide personalized predictions and serve as valuable references for clinical decision-making.

Pathologic Features of Primary Colon, Rectal, and Anal Malignancies

In USA, colorectal cancer is the third most commonly diagnosed cancer in men, second in women, as well as the third leading cause of cancer deaths (Siegel et al. in Cancer J Clin 73:1-112, 2023 [109]). Worldwide, colorectal cancer is the second leading cause of death and causes almost 916,000 deaths each year (Ferlay in Global cancer observatory: cancer today. International Agency for Research on Cancer, Lyon, 2020 [28]). Fortunately, due to the colon's surgical and endoscopic accessibility and functional redundancy, colorectal cancer is very treatable. Colonoscopic surveillance has the potential for not only providing tissue for the diagnosis of precancerous polyps and invasive carcinoma, but also preventing development of invasive carcinoma by the removal of precancerous lesions. This chapter discusses the clinical and pathologic features of the spectrum of epithelial, hematolymphoid, and mesenchymal malignant tumors of the colon, rectum, appendix, and anus.

Stage II Medullary Carcinoma of the Colon: A Surgery Case Report

Medullary carcinoma (MC) is a rare subtype of colorectal cancer, which presents with poorly differentiated histology and is often confused with conventional adenocarcinoma of the colon. While this form of colorectal cancer is rare, it often does not meet the high-risk criteria to qualify for adjuvant chemotherapy even with a favorable prognosis. Diagnosis of MC is a proven difficulty because of the lack of immunohistochemical stains on pathology seen in adenocarcinoma of the colon. Unlike adenocarcinoma of the colon, distant metastasis is rare. Patients diagnosed with MC have one- and two-year survival rates of 93% and 74%, respectively. The patient was a 75-year-old female diagnosed with MC of the sigmoid colon and a large uterine fibroid. In this case report, we discuss the high-risk indications of colorectal cancer and the recommended treatment of patients with stage II MC of the colon.

Medullary colonic carcinomas present with early-stage disease and do not express neuroendocrine markers by immunohistochemistry

Background

Medullary colonic carcinoma (MCC) is a rare and distinct phenotype of colorectal cancers characterized histologically by sheets of malignant cells with vesicular nuclei, prominent nucleoli, and abundant eosinophilic cytoplasm, exhibiting prominent infiltration by lymphocytes and neutrophilic granulocytes. We present the clinicopathologic and immunohistochemical characteristics of this rare tumor in our patient population.

Methods

Eleven cases diagnosed with MCC from 1996-2020 met the diagnostic histologic criteria and had tissue blocks available for further analysis. Immunohistochemistry for mismatch repair deficiency, CDX2, synaptophysin, and chromogranin, and microsatellite instability testing by polymerase chain reaction were performed. Additional clinical information was obtained from the electronic medical records.

Results

The median age at diagnosis was 69 years. MCC was more common in women (64%) than men (36%) and all (100%) cases involved the right colon. The median carcinoembryonic antigen level at diagnosis was 2.8 ng/mL. Lymphovascular invasion and perineural invasion occurred in 64% and 9% of cases, respectively. Synaptophysin and chromogranin showed no expression in any of the cases (0%), and CDX2 was only expressed in 18% of cases by immunohistochemistry. Most patients (73%) presented with stage II disease and 7 (64%) cases were microsatellite instability-high. Only lymph node metastasis showed an association with overall survival (OS) (hazard ratio 0.04, 95% confidence interval 0.0003-0.78; P=0.035). During a median follow up of 1.25 years, the median OS was not estimable as the survival curve did not reach the median point of survival, indicating that more than half of the patients were still alive at the end of the study.

Conclusion

Based on our experience, neuroendocrine markers, including synaptophysin and chromogranin, are not expressed in MCC, and many patients present with early-stage disease.

Exploring biomarkers and prognostic factors in uterine carcinosarcoma: An insight into L1CAM, CDX2, p53, and MSI status

BACKGROUND

Uterine Carcinosarcomas (UCS) are a rare type of cancer composed of an admixture of high-grade carcinomatous and sarcomatous elements. Clinicopathological prognostic factors in UCS are well established, but studies that approach the impact of biomarkers in this unusual disease are scarce. The study objective was to evaluate the prevalence and prognostic impact of a panel of prominent biomarkers in uterine carcinosarcoma (UCS) using an immunohistochemical characterization with four biomarkers.

METHODS AND FINDINGS

The internal database of a single Brazilian institution was carefully explored to select women diagnosed with UCS who were submitted to surgery and postoperative chemotherapy with carboplatin and paclitaxel between January 2012 and December 2017. Tissue microarrays containing UCS samples were evaluated by immunohistochemistry for L1CAM, CDX2, p53 and microsatellite instability markers. A total of 57 cases were included. The mean age was 65.3 years (standard deviation, SD 7.0). L1CAM was negative (score 0, no staining) in 27 (47.4%) patients. Of L1CAM-positive, 10 (17.5%) showed weak (score 1, <10%), 6 (10.5%) showed moderate (score 2, between 10-50%), and 14 (24.6%) showed strong L1CAM staining (score 3, ≧50%). dMMR occurred in 3 (5.3%) cases. The p53 was aberrantly expressed in 15 (26.3%) tumors. CDX2 was positive in 3 (5.3%) patients. The three-year progression-free survival (PFS) rate in the general population of the study was 21.2% (95% CI: 11.7-38.1) and the three-year overall survival (OS) rate was 29.4% (95% CI: 18.1-47.6). By multivariate analysis, the presence of metastases and CDX2-positive were significantly associated with poorer PFS (p < 0.001 and p = 0.002, respectively) and OS (p < 0.001 and p = 0.009, respectively).

CONCLUSION

The strong influence of CDX2 on prognosis requires further investigation. Biological or molecular variability may have impaired the assessment of the impact of the other markers on survival.

Medullary carcinoma of the colon: A comprehensive analysis of the National Cancer Database

PURPOSE

Medullary carcinomas (MC) of the colon are uncommon tumors. In this study, we analyzed demographic and disease characteristics as well as survival outcomes of MC versus undifferentiated (UDA) and poorly differentiated (PDA) adenocarcinomas (AC) of the colon.

MATERIALS AND METHODS

The National Cancer Database (2004-2018) was utilized to identify patients with colon cancer. Patient demographics (including age, gender, race), disease characteristics (including grade, TNM stage, carcinoembryonic levels, perineural and lymphovascular invasion, lymph node status, microsatellite stability, KRAS mutation, and primary tumor site), and facility type and location were evaluated. Chi-square tests were used to compare descriptive data. Cox Regression and Kaplan Meier analyses were used to analyze survival characteristics.

RESULTS

1,041,753 patients with colon cancer were identified of whom 2709 patients had MC and 897,902 had AC (136,597 PDA and 18,042 UDA). MC was seen in older patients (mean age 74 ± 13 years) and women (72.5% vs. 27.5% males). Most MCs were poorly differentiated (63.3%), and 82.4% of patients with MC had microsatellite instability. Fewer patients with MC had perineural invasion (15.6% vs. 22.0% in PDA and 22.4% in UDA, p < 0.001) and positive lymph nodes (38.4% versus 59.9% with PDA and 59.7% with UDA, p < 0.0001). MC diagnosis increased by year (Cochran-Armitage trend test, p < 0.0001). Kaplan Meir analysis revealed a better prognosis for patients with MC when compared to PDA or UDA (p < 0.001).

CONCLUSION

Given the rarity, pathologists should maintain a high suspicion for MC when encountering poorly differentiated or undifferentiated right-sided colon cancer with associated MSI-H.

Cerebral Metastases in Appendiceal Cancer: Comprehensive Review and Report of Rare Medullary Carcinoma Histology

Appendiceal cancer is an extremely rare malignancy, and its metastatic spread to the brain is even more unusual. We describe a 47-year-old female who presented with a rare cerebral appendiceal carcinoma metastasis, a case that is further remarkable for representing the first histologic diagnosis of primary medullary carcinoma in the appendix. Based on a comprehensive review of the English literature using PubMed, Embase, and Google Scholar, only six other cases of cerebral appendiceal metastases have been described.

Diagnostic and Prognostic Roles of CDX2 Immunohistochemical Expression in Colorectal Cancers

The study is aimed to evaluate the diagnostic and prognostic role of the immunohistochemical expression of the Caudal-type homeobox transcription factor 2 (CDX2) in colorectal cancers (CRCs) through a meta-analysis. By searching relevant databases, 38 articles were eligible to be included in this study. We extracted the information for CDX2 expression rates and the correlation between CDX2 expression and clinicopathological characteristics. The estimated rates of CDX2 expression were 0.882 [95% confidence interval (CI) 0.774−0.861] and 0.893 (95% CI 0.820−0.938) in primary and metastatic CRCs, respectively. Furthermore, based on their histologic subtype, CDX2 expression rates of adenocarcinoma and medullary carcinoma were 0.886 (95% CI 0.837−0.923) and 0.436 (95% CI 0.269−0.618), respectively. There was a significant difference in CDX2 expression rates between adenocarcinoma and medullary carcinoma in the meta-regression test (p < 0.001). In addition, CDX2 expression was significantly lower in CRCs with the BRAFV600E mutation than in CRCs without mutation. Patients with CDX2 expression had better overall and cancer-specific survival rates than those without CDX2 expression. Thus, CDX2 is a useful diagnostic and prognostic marker CRCs.

Colorectal medullary carcinoma: heterogeneous presentations of a rare clinico-pathological entity. Report of two cases

Colorectal medullary carcinoma (CMC) is a rare subset of minimally differentiated carcinomas. CMC tend to be right-sided and present at an advanced stage. Despite this, distant metastases are rare at presentation. The liver and the regional lymph nodes represent the most common sites of metastases. Most of the time, CMCs exhibit mismatch repair deficiency and a strong association with high-level microsatellite instability. There is no conspicuous data regarding treatment strategies and short-term outcomes. CMC is supposed to be related to better prognosis compared to poorly-differentiated and undifferentiated colonic adenocarcinomas, but reports are controversial.This lesion, with heterogeneous presentations and unclear prognostic significance, may be unfamiliar to histopathologists and can lead to diagnostic uncertainty and overtreatments.Our aim is to renew the attention to this rare histological subtype through the report of two cases.

Clinical and Molecular Characteristics of Rare Malignant Tumors of Colon and Rectum

Simple Summary

Tumors of colon and rectum other than adenocarcinomas represent a neglected issue from clinical and laboratory points of view because of their rarity. In this review, we summarize and describe the rare histologic entities occurring in colon and rectum. Clinical and pathologic characteristics, prognostic behavior, treatments, and altered genes are reported to provide readers with a paramount and comparative perspective. In relation to this, we propose that improvements in registries and multidisciplinary research are warranted to ameliorate their management.

Abstract

The most frequent form of colorectal cancer is represented by adenocarcinoma being about 98% of tumor histological types. However, other rare histotypes can be found in colon and rectum (adenosquamous, goblet cell adenocarcinoma, lymphoma, medullary carcinoma, melanoma, mesenchymal, neuroendocrine, plasmacytoma, signet ring, squamous tumors). Altogether, these forms account for less than 2% of colorectal tumors. There are no specific diagnostic or therapeutic recommended approaches and most of the information available from literature derives from small and retrospective clinical series. In the present study, we provide a paramount and updated view on clinical and biologic characteristics of rare colorectal tumors.

Sidedness determines clinical characteristics and survival outcomes in medullary adenocarcinoma of the colon

Colon medullary adenocarcinoma (MAC) is a rare histologic subtype. Clinical presentation and cancer outcomes of MAC, compared to colon adenocarcinoma (AC), remain incompletely described. Annual age-adjusted incidence rates were computed using Surveillance, Epidemiology, and End Results (2002–2017). A cohort analysis using the National Cancer Database (2010–2016) compared patient characteristics in an unmatched dataset and prognostic characteristics in a 1:1 matched subset. Reported annual age-adjusted incidence of MAC has significantly increased, with an average annual percent change (APC) increase of 23.8% (95% CI: 19.2–28.6); concurrent AC incidence declined (APC: − 2.8, 95% CI: − 3.1 to − 2.8). Analyses of 1018 MAC and 210,784 AC unmatched patients showed that MAC patients were more often older, female, and white, with higher disease stage, poorly-differentiated tumors, right-sided laterality, and lymphovascular invasion (all p < 0.0001). Among those with known microsatellite status, instability was more prevalent among MAC than AC patients (82% vs. 24%, p < 0.0001). Multivariate analyses of the matched dataset revealed that MAC histology was not independently associated with overall survival. However, when stratifying by laterality, left-sided MAC was associated with shorter survival when compared to right-sided MAC (HR 1.66, 95% CI 1.16–2.38) and right-sided AC (HR 1.54, 95% CI 1.12–2.12). The reported incidence of MAC is increasing, in contrast to the declining incidence of AC. MAC clinical and molecular features are distinct from AC and likely account for outcome differences. Overall, left-sided MAC was associated with the shortest OS. Molecular profiling may improve treatment guidelines for MAC.

Medullary Carcinoma of the Gastrointestinal Tract: Report on Two Cases with Immunohistochemical and Molecular Features

Medullary carcinoma of the colon is a rare histological variant characterized by a poorly differentiated morphology, an aberrant immunophenotype, and microsatellite instability. Despite the lack of glandular differentiation, medullary carcinoma is reported to have a good prognosis. It is typically located in the right colon and frequently affects older women. Due to its clinical, histological, biological, and genetic peculiarity, medullary carcinoma requires an accurate diagnosis and the awareness of this diagnostic possibility. We describe the morphological, immunohistochemical, and molecular findings of two interesting cases, the first one in the right colon of a patient and the second one in the terminal ileum of a patient with Crohn's disease. Deeper knowledge of all the biological and clinical features will allow appropriate and specific treatment of this tumor in the future.

Advances in Intracellular Calcium Signaling Reveal Untapped Targets for Cancer Therapy

Intracellular Ca2+ distribution is a tightly regulated process. Numerous Ca2+ chelating, storage, and transport mechanisms are required to maintain normal cellular physiology. Ca2+-binding proteins, mainly calmodulin and calbindins, sequester free intracellular Ca2+ ions and apportion or transport them to signaling hubs needing the cations. Ca2+ channels, ATP-driven pumps, and exchangers assist the binding proteins in transferring the ions to and from appropriate cellular compartments. Some, such as the endoplasmic reticulum, mitochondria, and lysosomes, act as Ca2+ repositories. Cellular Ca2+ homeostasis is inefficient without the active contribution of these organelles. Moreover, certain key cellular processes also rely on inter-organellar Ca2+ signaling. This review attempts to encapsulate the structure, function, and regulation of major intracellular Ca2+ buffers, sensors, channels, and signaling molecules before highlighting how cancer cells manipulate them to survive and thrive. The spotlight is then shifted to the slow pace of translating such research findings into anticancer therapeutics. We use the PubMed database to highlight current clinical studies that target intracellular Ca2+ signaling. Drug repurposing and improving the delivery of small molecule therapeutics are further discussed as promising strategies for speeding therapeutic development in this area.

Medullary Carcinoma of the Colon: A Histopathologic Challenge

Medullary carcinoma (MC) of the colon is a rare and unique histologic subtype of colorectal cancer. It is commonly associated with deficient mismatch repair proteins and has a strong association with Lynch syndrome. Diagnosis is challenging as it does not have the usual immunohistochemical stains on pathology seen in colorectal adenocarcinoma. Here, we discuss an interesting case of MC of the colon that was metastatic on presentation and constituted a diagnostic challenge.

Is medullary carcinoma of the colon underdiagnosed? An audit of poorly differentiated colorectal carcinomas in a large national health service teaching hospital

AIMS

Medullary carcinoma is an uncommon colorectal tumour which appears poorly differentiated histologically. Consequently, it may be confused with poorly differentiated adenocarcinoma not otherwise specified (NOS). The principal aim of this study was to review a large series of poorly differentiated colorectal cancers resected at a large National Health Service (NHS) Teaching Hospital to determine how often medullary carcinomas were misclassified . Secondary aims were to investigate how often neuroendocrine differentiation or metastatic tumours were considered in the differential diagnosis, and compare clinico-pathological features between medullary and poorly differentiated adenocarcinoma NOS.

METHODS AND RESULTS

Histology slides from 302 colorectal cancer resections originally reported as poorly differentiated adenocarcinoma were reviewed and cases fulfilling World Health Organisation (WHO) criteria for medullary carcinoma identified. The original pathology report was examined for any mention of medullary phenotype, consideration of neuroendocrine differentiation or consideration of metastasis from another site. Clinico-pathological features were compared to poorly differentiated adenocarcinoma NOS. Only one-third of medullary carcinomas were correctly identified between 1997 and 2018. The other two-thirds were reported as poorly differentiated adenocarcinoma NOS. The possibility of an extracolonic origin or neuroendocrine carcinoma was considered in 21 and 27% of reports. Most medullary carcinomas exhibited mismatch repair deficiency, were located in ascending colon and caecum and had a lower rate of vascular channel invasion and lymph node metastasis compared to poorly differentiated adenocarcinoma.

CONCLUSIONS

Medullary carcinoma of the colon is often mistaken for poorly differentiated adenocarcinoma NOS and occasionally for neuroendocrine or metastatic carcinoma. Greater familiarity with morphological criteria and use of mismatch repair protein staining should improve diagnosis.

Expression of Calretinin, Marker of Mesothelial Differentiation, in Pancreatic Ductal Adenocarcinoma: A Potential Diagnostic Pitfall

OBJECTIVE

Pancreatic ductal adenocarcinoma is one of the most common causes of "peritoneal carcinomatosis" and has an insidious growth pattern. Thus, it falls into the differential diagnosis of other peritoneal malignancies including malignant mesothelioma. Recently, we have encountered an undifferentiated pancreatic carcinoma presenting with peritoneal disease and exhibiting immunoreactivity to calretinin, mimicking mesothelioma. In this study, we explored the incidence of calretinin expression in pancreatic ductal adenocarcinoma.

MATERIALS AND METHODS

Calretinin immunohistochemical staining was performed on the tissue microarrays (TMAs), which were created using three 0.6 mm diameter punches per tumor (n=113). Distribution and intensity of expression were evaluated.

RESULTS

The TMAs contained 86 well/moderately differentiated and 27 poorly differentiated/undifferentiated carcinomas. Calretinin was positive in nine tumors (8%); six with diffuse and strong staining, three with focal and/or weak staining. The incidence of calretinin expression was 15% in poorly differentiated/undifferentiated carcinomas (vs. 6% in well/moderately differentiated carcinomas, p=0.03).

CONCLUSIONS

Pancreatic ductal adenocarcinomas, especially when poorly differentiated/undifferentiated, may be diffusely and strongly positive for calretinin creating a potential diagnostic challenge with malignant mesothelioma. Therefore, caution should be exercised when using this marker to explore a diagnosis of malignant mesothelioma. Tumors expressing calretinin without other mesothelial markers should prompt a careful evaluation of the morphologic and immunohistochemical features to exclude other malignancies. If the diagnosis of pancreatic ductal adenocarcinoma is considered, ductal differentiation can be demonstrated by using additional immunohistochemical markers such as mucin-related glycoproteins (MUC1, MUC5AC) and/or oncoproteins (CEA, B72.3, CA125).

An Algorithmic Immunohistochemical Approach to Define Tumor Type and Assign Site of Origin

Immunohistochemistry represents an indispensable complement to an epidemiology and morphology-driven approach to tumor diagnosis and site of origin assignment. This review reflects the state of my current practice, based on 15-years' experience in Pathology and a deep-dive into the literature, always striving to be better equipped to answer the age old questions, "What is it, and where is it from?" The tables and figures in this manuscript are the ones I "pull up on the computer" when I am teaching at the microscope and turn to myself when I am (frequently) stuck. This field is so exciting because I firmly believe that, through the application of next-generation immunohistochemistry, we can provide better answers than ever before. Specific topics covered in this review include (1) broad tumor classification and associated screening markers; (2) the role of cancer epidemiology in determining pretest probability; (3) broad-spectrum epithelial markers; (4) noncanonical expression of broad tumor class screening markers; (5) a morphologic pattern-based approach to poorly to undifferentiated malignant neoplasms; (6) a morphologic and immunohistochemical approach to define 4 main carcinoma types; (7) CK7/CK20 coordinate expression; (8) added value of semiquantitative immunohistochemical stain assessment; algorithmic immunohistochemical approaches to (9) "garden variety" adenocarcinomas presenting in the liver, (10) large polygonal cell adenocarcinomas, (11) the distinction of primary surface ovarian epithelial tumors with mucinous features from metastasis, (12) tumors presenting at alternative anatomic sites, (13) squamous cell carcinoma versus urothelial carcinoma, and neuroendocrine neoplasms, including (14) the distinction of pheochromocytoma/paraganglioma from well-differentiated neuroendocrine tumor, site of origin assignment in (15) well-differentiated neuroendocrine tumor and (16) poorly differentiated neuroendocrine carcinoma, and (17) the distinction of well-differentiated neuroendocrine tumor G3 from poorly differentiated neuroendocrine carcinoma; it concludes with (18) a discussion of diagnostic considerations in the broad-spectrum keratin/CD45/S-100-"triple-negative" neoplasm.

Practical Application of Lineage-Specific Immunohistochemistry Markers: Transcription Factors (Sometimes) Behaving Badly

CONTEXT.—

Transcription factors (TFs) are proteins that regulate gene expression and control RNA transcription from DNA. Lineage-specific TFs have increasingly been used by pathologists to determine tumor lineage, especially in the setting of metastatic tumors of unknown primary, among other uses. With experience gathered from its daily application and increasing pitfalls reported from immunohistochemical studies, these often-touted highly specific TFs are not as reliable as once thought.

OBJECTIVES.—

To summarize the established roles of many of the commonly used TFs in clinical practice and to discuss known and potential sources for error (eg, false-positivity from cross-reactivity, aberrant, and overlap "lineage-specific" expression) in their application and interpretation.

DATA SOURCES.—

Literature review and the authors' personal practice experience were used. Several examples selected from the University Health Network (Toronto, Ontario, Canada) are illustrated.

CONCLUSIONS.—

The application of TF diagnostic immunohistochemistry has enabled pathologists to better assess the lineage/origin of primary and metastatic tumors. However, the awareness of potential pitfalls is essential to avoid misdiagnosis.

Morphology and Molecular Features of Rare Colorectal Carcinoma Histotypes

Several histopathological variants of colorectal carcinoma can be distinguished, some associated with specific molecular profiles. However, in routine practice, ninety/ninety-five percent of all large bowel tumors are diagnosed as conventional adenocarcinoma, even though they are a heterogeneous group including rare histotypes, which are often under-recognized. Indeed, colorectal cancer exhibits differences in incidence, location of tumor, pathogenesis, molecular pathways and outcome depending on histotype. The aim is therefore to review the morphological and molecular features of these rare variants of intestinal carcinomas which may hold the key to differences in prognosis and treatment.

Human Papillomavirus (HPV)-associated Lymphoepithelioma-like Carcinoma of the Vagina and Anal Canal: A Rare Variant of Squamous Cell Carcinoma

Lymphoepithelioma-like carcinoma (LELC) is an uncommon variant of squamous cell carcinoma, which is histologically identical to lymphoepithelial carcinoma of the nasopharynx. LELCs have been reported at a variety of sites, including the stomach, salivary gland, thymus, cervix, endometrium, breast, skin, bladder, and lung. We report 2 LELCs of the vagina and 1 of the anal canal, the first report of LELC at the latter site. All 3 neoplasms were diffusely positive with p16 (block-type immunoreactivity) and the anal canal lesion contained high-risk human papillomavirus type 16; the 2 vaginal neoplasms underwent human papillomavirus testing but were unsuitable for analysis. All cases were Epstein-Barr virus negative. In reporting these cases, we highlight the potential for misdiagnosis and suggest an association with human papillomavirus infection similar to LELCs in the uterine cervix.

Raman spectroscopy for the diagnosis of unlabeled and unstained histopathological tissue specimens

AIM

To investigate the possibility of diagnosing gastric cancer from an unstained pathological tissue using Raman spectroscopy, and to compare the findings to those obtained with conventional histopathology.

METHODS

We produced two consecutive tissue specimens from areas with and without cancer lesions in the surgically resected stomach of a patient with gastric cancer. One of the two tissue specimens was stained with hematoxylin and eosin and used as a reference for laser irradiation positioning by the spectroscopic method. The other specimen was left unstained and used for Raman spectroscopy analysis.

RESULTS

A significant Raman scattering spectrum could be obtained at all measurement points. Raman scattering spectrum intensities of 725 cm^-1 and 782 cm^-1, are associated with the nucleotides adenine and cytosine, respectively. The Raman scattering spectrum intensity ratios of 782 cm^-1/620 cm^-1, 782 cm^-1/756 cm^-1, 782 cm^-1/1250 cm^-1, and 782 ​​cm^-1/1263 cm^-1 in the gastric adenocarcinoma tissue were significantly higher than those in the normal stomach tissue.

CONCLUSION

The results of this preliminary experiment suggest the feasibility of our spectroscopic method as a diagnostic tool for gastric cancer using unstained pathological specimens.

CDX2 expression is concordant between primary colorectal cancer lesions and corresponding liver metastases independent of chemotherapy: a single-center retrospective study in Japan

Objective

Loss of caudal-type homeobox transcription factor 2 (CDX2) expression in colorectal cancers (CRCs) has recently been proposed as a promising predictive biomarker for not only prognosis but also response to chemotherapy. However, the relationship between alterations in CDX2 expression during cancer progression and response to chemotherapy remains unclear. We herein aimed to determine the concordance of CDX2 expression between primary CRCs and corresponding liver metastases, in association with chemotherapy.

Results

Primary CRCs exhibited heterogeneous CDX2 expression. Seven of the 144 CRCs in the cohort (4.9%, 95% confidential interval, 2.0%–9.8%) were CDX2-negative. The concordance rate of the CDX2 expression status in patients who did not receive chemotherapy was 100% (P = 0.041), whereas the concordance rate among patients who received chemotherapy only after primary resection was 96.3% (P = 0.005). Moreover, the concordance rate in patients who received chemotherapy before both primary resection and liver metastasectomy was 100% (P < 0.001).

Conclusion

CDX2 expression status was highly concordant between primary CRCs and corresponding liver metastases, independent of chemotherapy, suggesting that the CDX2 expression status in CRCs was not affected by metastasis or chemotherapy.

Methods

A total of 144 consecutive patients with CRC who were treated at a single center in Japan between 2006 and 2014 were included. Formalin-fixed paraffin-embedded whole sections of surgically resected primary CRCs and corresponding liver metastases were assessed for CDX2 expression by immunohistochemistry.

A resected case of medullary carcinoma of the ascending colon followed by infarction of the greater omentum mimicking anastomotic leakage

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Medullary carcinoma should be distinguished from other more aggressive, non-glandular tumors of the colon, because medullary carcinoma appears to have a better survival outcome than undifferentiated colon adenocarcinoma.

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Omental infarction should be considered in the differential diagnosis of acute abdomen after surgery.

Introduction

Medullary carcinoma is a rare type of colorectal adenocarcinoma, and omental infarction is a rare cause of acute abdomen.

Presentation of case

A 72-year-old woman underwent single-incision laparoscopic right hemicolectomy for ascending colon cancer. Pathological examination showed a medullary carcinoma (MC) of T4aN0M0 Stage IIB. Her postoperative course was uneventful, and she was discharged on postoperative day (POD) 6. From POD 7, she suffered from fever, and she returned to the hospital on POD 9. Plain computed tomography showed free air beside the anastomotic site around the elevated density of fat tissue and gallbladder wall thickening with a gallstone. Suspecting anastomotic leakage with acute cholecystitis, probe laparotomy was performed. Intraoperative observation confirmed omental infarction with acute cholecystitis, and no leakage was found at the anastomotic site. Therefore, the necrotic part of the greater omentum was resected, and cholecystectomy was performed. She has remained well, with no evidence of recurrent cancer during the 12 months of follow-up without chemotherapy after the surgery for MC of the ascending colon.

Discussion

MC should be distinguished from other more aggressive, non-glandular tumors of the colon because MC appears to have a better survival outcome than undifferentiated colon adenocarcinoma. Omental infarction should be considered in the differential diagnosis of acute abdomen after surgery.

Conclusion

A rare case of medullary carcinoma of the ascending colon followed by infarction of the greater omentum mimicking anastomotic leakage is presented.

Gastric Carcinomas With Lymphoid Stroma: Categorization and Comparison With Solid-Type Colonic Carcinomas

OBJECTIVES

To determine whether histologic features could help identify gastric carcinomas with lymphoid stroma associated with microsatellite instability (MSI) (ie, "medullary carcinomas"), Epstein-Barr virus (EBV) infection (termed lymphoepithelioma-like carcinomas in other organ systems), or neither.

METHODS

We identified 17 solid-type gastric carcinomas with lymphoid stroma, assessed EBV and MSI status, and compared features across groups. We also compared them with 51 solid-type colorectal adenocarcinomas.

RESULTS

In the stomach, EBV-associated carcinomas (n = 8) contained intratumoral germinal centers (P = .024) and eosinophils (P = .030) and lacked necrosis (P = .019) compared with MSI-associated carcinomas (n = 5) and non-EBV, non-MSI carcinomas (n = 4). In the colon, MSI-driven carcinomas (n = 40) more frequently contained intratumoral lymphocytes (P = .017) and neutrophils (P = .0050) and less often metastasized to distant sites (P = .0040) than poorly differentiated carcinomas lacking MSI (n = 11).

CONCLUSIONS

Morphology may help classify gastric carcinomas with lymphoid stroma, although ancillary testing appears more reliable. Lymphoepithelioma-like carcinoma and medullary carcinoma should not be used interchangeably.

Practical Immunohistochemistry in Neoplastic Pathology of the Gastrointestinal Tract, Liver, Biliary Tract, and Pancreas

CONTEXT

- Immunomarkers with diagnostic, therapeutic, or prognostic values have been increasingly used to maximize the benefits of clinical management of patients with neoplastic diseases of the gastrointestinal tract, liver, biliary tract, and pancreas.

OBJECTIVES

- To review the characteristics of immunomarkers that are commonly used in surgical pathology practice for neoplasms of the gastrointestinal tract, liver, biliary tract, and pancreas, and to summarize the clinical usefulness of immunomarkers that have been discovered in recent years in these fields.

DATA SOURCES

- Data sources include literature review, authors' research data, and personal practice experience.

CONCLUSIONS

- Immunohistochemistry is an indispensable tool for the accurate diagnosis of neoplastic diseases of the gastrointestinal tract, liver, biliary tract, and pancreas. Useful immunomarkers are available to help distinguish malignant neoplasms from benign conditions, determine organ origins, and subclassify neoplasms that are morphologically and biologically heterogeneous. Specific immunomarkers are also available to help guide patient treatment and assess disease aggressiveness, which are keys to the success of personalized medicine. Pathologists will continue to play a critical role in the discovery, validation, and application of new biomarkers, which will ultimately improve patient care.

Medullary colonic carcinoma with microsatellite instability has lower survival compared with conventional colonic adenocarcinoma with microsatellite instability

Introduction

Colorectal medullary carcinoma (MC) is a rare subtype of poorly differentiated adenocarcinoma (PDA) with unclear prognostic significance. Microsatellite instable (MSI) colorectal carcinomas have demonstrated better prognosis in clinical stage II.

Aim

To analyze the survival and clinicopathological characteristics of MCs versus PDAs with MSI in clinical stage III.

Material and methods

We studied 22 cases of PDAs with MSI versus 10 MCs.

Results

Of the 10 MCs, 7 patients were men; the mean age was 57.8 ±5.6 years. The mean tumor size was 9.6 ±4.1 cm, and the primary site was the right colon in 9; 7 patients showed lymph node metastases (LNM) and lymphovascular invasion (LVI). Of the 22 PDA cases, 12 (54.5%) were women with a mean age of 75 ±16.1 years. The mean tumor size was 6.4 ±3.2 cm. Twelve (54.5%) presented in the right colon, 21 (95.5%) showed LNM and 7 (31.8%) LVI. Follow-up was 32 ±8 months, with a 5-year overall survival of 42.9% for MCs and 76.6% for PDAs (p = 0.048). Univariate analysis found local recurrence (p = 0.001) and medullary subtype (p = 0.043) associated with lower survival.

Conclusions

Medullary carcinomas were of greater tumor size and associated with more LVI and worse survival versus PDAs with MSI in stage III.

Aberrant Expression of Calretinin, D2-40 and Mesothelin in Mucinous and Non-Mucinous Colorectal Carcinomas and Relation to Clinicopathological Features and Prognosis

CRC is a heterogeneous disease in terms of morphology, invasive behavior, metastatic capacity, and clinical outcome. Recently, many so-called mesothelial markers, including calretinin, D2-40, WT1, thrombomodulin, mesothelin, and others, have been certified. The aim of this study was to assess the immunohistochemical expression of calretinin and other mesothelial markers (D2-40 and mesothelin) in colorectal mucinous adenocarcinoma (MA) and non mucinous adenocarcinoma (NMA) specimens and relation to clinicopathological features and prognosis using manual tissue microarray technique. We studied tumor tissue specimens from 150 patients with colorectal MA and NMA who underwent radical surgery from January 2007 to January 2012. High-density manual tissue microarrays were constructed using a modified mechanical pencil tip technique, and paraffin sections were submitted for immunohistochemistry using Calretinin, D2-40 and mesothelin expressions. We found that NMA showed significantly more calretinin and D2-40 expression than MA In contrast, no statistically significant difference between NMA and MA was detected in mesothelin expression. There were no statistically significant relations between any of the clinicopathological or histological parameters and any of the three markers. In a univariate analysis, neither calretinin nor D2-40 expressions showed any significant relations to DFS or OS. However, mesothelin luminal expression was significantly associated with worse DFS. Multivariate Cox regression analysis proved that luminal mesothelin expression was an independent negative prognostic factor in NMA. In conclusion, Calretinin, D2-40 and mesothelin are aberrantly expressed in a proportion of CRC cases with more expression in NMA than MA. Aberrant expression of these mesothelial markers was not associated with clinicopathological or histological features of CRCs. Only mesothelin expression appears to be a strong predictor of adverse prognosis.

Cdx2 Expression and Intestinal Metaplasia Induced by H. pylori Infection of Gastric Cells Is Regulated by NOD1-Mediated Innate Immune Responses

Chronic infection with the bacterial Helicobacter pylori is a major cause of gastric and duodenal ulcer disease, gastric mucosal atrophy, and cancer. H. pylori-induced expression of the intestinal epithelial-specific transcription factor caudal-related homeobox 2 (Cdx2) contributes to intestinal metaplasia, a precursor event to gastric cancer. Given a role for the bacterial pattern recognition molecule nucleotide-binding oligomerization domain 1 (NOD1) in the innate immune response to bacterial infection, we investigated mechanisms used by NOD1 to regulate H. pylori infection and its propensity towards the development of intestinal metaplasia. We found that Cdx2 was induced by H. pylori infection in both normal and neoplastic gastric epithelial cells in a manner that was inversely related to NOD1 signaling. Mechanistic investigations revealed that Cdx2 induction relied upon activation of NF-κB but was suppressed by NOD1-mediated activation of TRAF3, a negative regulator of NF-κB. In vivo, prolonged infection of NOD1-deficient mice with H. pylori led to increased Cdx2 expression and intestinal metaplasia. Furthermore, gastric epithelial cells from these mice exhibited increased nuclear expression of the NF-κB p65 subunit and decreased expression of TRAF3. Overall, our findings illuminated a role for NOD1 signaling in attenuating H. pylori-induced Cdx2 expression in gastric epithelial cells, suggesting a rationale to augment NOD1 signaling in H. pylori-infected patients to limit their risks of accumulating precancerous gastric lesions.

Pathologic Features of Primary Colon, Rectal, and Anal Malignancies

In the United States, colorectal cancer is the third most commonly diagnosed cancer in both men and women, as well as the third leading cause of cancer deaths (Colorectal cancer facts & figures 2014–2016, 2014 [2]). Worldwide, colorectal cancer is the fourth leading cause of death and causes almost 700,000 deaths each year (Cancer: fact sheet No. 297, 2015 [55]). This chapter discusses the clinical and pathologic features of the spectrum of epithelial, hematolymphoid, and mesenchymal malignant tumors of the colon, rectum, appendix, and anus.

Current concepts of colorectal cancer resection pathology

The discussion of pathology results is one of the important items in the multidisciplinary meeting. These results describe not only the adequacy of earlier treatments (neoadjuvant therapy, surgery), but guide subsequent treatment decisions by providing staging information and additional prognostic and predictive factors. In the era of next-generation sequencing, every so often the emphasis is put on the molecular background of tumours, but the information that can be retrieved from the resection specimen remains essential for optimal patient care. In the current review the different surgical approaches will be described, together with the relevant macroscopic evaluations. Microscopic features will be addressed, giving an overview that is aimed at optimal information exchange in the multidisciplinary meeting. Finally, special requirements for reporting local excisions and specimen after neoadjuvant therapy will be discussed.

The Increasing Relevance of Tumour Histology in Determining Oncological Outcomes in Colorectal Cancer

Colorectal cancer is not just one type of cancer. Differences in outcome and reaction to treatment can at least be partly explained by different histological and molecular subtypes. Recognition of these differences may influence treatment decisions. However, there is huge variation in the amount of information that is available. Several tumour types such as mucinous carcinoma, signet ring cell carcinoma, neuroendocrine carcinoma and adenosquamous carcinoma have such a distinct phenotype that they are readily recognised. However, due to the rarity of signet ring cell carcinoma and adenosquamous carcinoma, limited data are available. More recently defined subtypes, like medullary carcinoma, serrated adenocarcinoma and micropapillary carcinoma, are not adequately diagnosed, which limits research possibilities using large-scale data from registries. In the current review, we systematically describe the histologic subtypes with the clinical and molecular background. We evaluate their prognosis compared to adenocarcinoma not otherwise specified and speculate about the clinical relevance.

Application of immunohistochemistry in gastrointestinal and liver neoplasms: new markers and evolving practice

CONTEXT

Diagnosis of primary gastrointestinal and liver neoplasms is usually straightforward. Immunohistochemistry is most helpful to differentiate metastatic carcinomas with morphologic similarity and to resolve tumors of unknown origin. Recently, several new markers highly sensitive and specific for primary liver and gastrointestinal tumors have been discovered. Their potential diagnostic application has not been widely appreciated by general practicing pathologists. In addition, a new trend in immunohistochemistry application has started, focusing on assessing predictive markers (such as human epidermal growth factor receptor 2) and mutation-specific markers (v-raf murine sarcoma viral oncogene homolog B V600E) to directly guide clinical management. Practicing pathologists need to be aware of and prepared for this evolving trend.

OBJECTIVES

To summarize the usefulness of several recently discovered immunohistochemical markers in the study of gastrointestinal and liver tumors; to suggest the most current and effective immunohistochemical panels addressing common diagnostic challenges for these tumors; to share practical experience and useful tips for human epidermal growth factor receptor 2 testing in gastric and gastroesophageal junction adenocarcinoma and v-raf murine sarcoma viral oncogene homolog B V600E immunohistochemistry in colorectal carcinoma.

DATA SOURCES

Sources include literature review, and authors' research data and practice experience. The cases illustrated are selected from the pathology archives of the Geisinger Medical Center (Danville, Pennsylvania).

CONCLUSIONS

Application of immunohistochemistry in gastrointestinal and liver tumors continues to evolve. New tumor-specific markers constantly emerge and help pathologists to further improve diagnostic accuracy. Assessment of predictive and prognostic markers by immunohistochemistry in routine pathologic diagnosis is a new trend and will greatly facilitate the advancement of personalized cancer therapy.

Immunohistochemistry in undifferentiated neoplasm/tumor of uncertain origin

CONTEXT

Immunohistochemistry has become an indispensable ancillary study in the identification and classification of undifferentiated neoplasms/tumors of uncertain origin. The diagnostic accuracy has significantly improved because of the continuous discoveries of tissue-specific biomarkers and the development of effective immunohistochemical panels.

OBJECTIVES

To identify and classify undifferentiated neoplasms/tumors of uncertain origin by immunohistochemistry.

DATA SOURCES

Literature review and authors' research data and personal practice experience were used.

CONCLUSIONS

To better guide therapeutic decisions and predict prognostic outcomes, it is crucial to differentiate the specific lineage of an undifferentiated neoplasm. Application of appropriate immunohistochemical panels enables the accurate classification of most undifferentiated neoplasms. Knowing the utilities and pitfalls of each tissue-specific biomarker is essential for avoiding potential diagnostic errors because an absolutely tissue-specific biomarker is exceptionally rare. We review frequently used tissue-specific biomarkers, provide effective panels, and recommend diagnostic algorithms as a standard approach to undifferentiated neoplasms.

Medullary colorectal carcinoma revisited: a clinical and pathological study of 102 cases

AIM

Medullary carcinoma is a recently described subtype of mismatch repair deficient (MMRd) colorectal carcinoma (CRC) which, despite being poorly differentiated by traditional morphological criteria, has been reported to have a good prognosis. We investigated the pathological and clinical features of medullary CRC in an unselected cohort of CRCs undergoing surgical resection.

METHODS

All CRCs resected within a single health district database from 1998 to 2012 were categorized prospectively and underwent retrospective review to identify 91 medullary CRCs, with 11 additional cases from 2013 to 2014. Strict criteria were employed to diagnose medullary carcinoma requiring both MMRd and greater than 90 % of the tumor to demonstrate typical morphology, including solid growth. The demographic and pathological features, as well as all-cause survival, were compared with other CRCs, and specifically to other MMRd CRCs.

RESULTS

From 1998 to 2012, 91 of 3,295 CRCs (2.8 %) were of the medullary type. Medullary CRC was more likely to arise in females than males (3.3:1; p < 0.0001), the elderly (mean age 77 vs. 71 years; p < 0.001), and the right colon (86 %; p < 0.0001). All medullary CRCs demonstrated MMR deficiency (considered an inclusion criteria) and 86 % were BRAFV600E-mutated (p < 0.0001). Thirty-day mortality after resection was higher in medullary CRC (4.6 vs. 1.7 %; p = 0.049). On univariate analysis, survival was not better than well-differentiated or other MMRd tumors. However, using a multivariate model, a medullary phenotype was protective (hazard ratio of death 0.54, 95 % CI 0.30-0.96; p = 0.037).

CONCLUSIONS

Medullary CRC is more common than previously reported, frequently presents with locally advanced disease, and may be associated with higher mortality at 30 days after resection. Despite this, when strict criteria are used for diagnosis, the overall survival is favorable when compared with CRCs with equivalent demographic and pathological characteristics.

The clinical perspectives of CDX2 expression in colorectal cancer: a qualitative systematic review

INTRODUCTION

Homeobox genes are often deregulated in cancer. They can have both oncogenic and tumor-suppressing potential. The Caudal-related homeobox transcription factor 2 (CDX2) is an intestine-specific transcription factor. It is implicated in differentiation, proliferation, cell-adhesion, and migration. CDX2 has been proposed as a tumor suppressor in colorectal cancer but its role is still controversial. This systematic review were undertaken in order to clarify CDX2s role in colorectal cancer.

METHODS

A literature search was performed in the MEDLINE database from 1966 to February 2014. Only studies in which all or a part of the experimental design were performed on human colorectal cancer tissue were included. Thus, studies solely performed in cell-lines or animal models were excluded.

RESULTS

Fifty-two articles of relevance were identified. CDX2 expression was rarely lost in colorectal cancers, however the expression pattern may often be heterogeneous within the tumor and can be selectively down regulated at the invasive front and in tumor buddings. Loss of CDX2 expression is probably correlated to tumor grade, stage, right-sided tumor location, MMR-deficiency, CIMP, and BRAF mutations. The CDX2 gene is rarely mutated but the locus harboring the gene is often amplified and may suggest CDX2 as a linage-survival oncogene. CDX2 might be implicated in cell proliferation and migration through cross-talk with the Wnt-signaling pathway, tumor-stroma proteins, and inflammatory cytokines.

CONCLUSION

A clear role for CDX2 expression in colorectal cancer remains to be elucidated, and it might differ in relation to the underlying molecular pathways leading to the cancer formation.

Prognostic biomarkers in colorectal cancer: where do we stand?

Colorectal cancer remains a major cause of cancer-related death worldwide. One way to reduce its staggering mortality rate and socio-economic burden is to predict outcome based on the aggressiveness of the tumor biology in order to treat patients accordingly to their risk profile. As such, it comes as no surprise that prognostic biomarker discovery is a hot topic in colorectal cancer research. The last two decades have literally produced tons of new data and an avalanche of potential clinically applicable biomarkers. This review explores and summarizes data concerning the prognostic strength and clinical utility of current and future tissue biomarkers in the diagnosis and treatment of colorectal cancer.

Calretinin expression in high-grade invasive ductal carcinoma of the breast is associated with basal-like subtype and unfavorable prognosis

Calretinin, a calcium-binding protein, is a widely used marker for mesothelial differentiation. There is accumulating evidence of calretinin expression in epithelial and mesenchymal malignancies, as well. The objectives of this study were to (1) further delineate the expression of calretinin in grade 3 breast carcinomas in the context of molecular subtypes and (2) identify the impact of calretinin expression on overall and disease-free survival. On the basis of immunohistochemical expression of estrogen receptor, progesterone receptor, human epidermal growth factor receptor-2 (HER2), cytokeratin 5/6, and epidermal growth factor receptor, 214 grade 3 invasive ductal carcinomas were stratified into 36 luminal A, 63 luminal B, 24 HER2 positive, 81 basal-like (including 13 metaplastic carcinomas), and 10 unclassified. Tissue microarrays were analyzed for immunohistochemical expression of calretinin. High-level calretinin expression was identified in a significant proportion of basal-like (54.3%), HER2 (33.3%), and unclassified (30%) tumors. In contrast, luminal A and B subtypes demonstrated high-level calretinin expression in only 11.1% and 12.7%, respectively (P < .0001). Within the basal-like group, 38.5% of the metaplastic carcinomas demonstrated high-level expression, associated predominantly with the epithelial component and squamous metaplasia. High-level calretinin expression was strongly associated with decreased overall survival in the entire cohort of grade 3 cancer (P = .0096) and in the basal-like group (P = .039). Multivariate analysis revealed that both tumor stage and high-level calretinin expression were independent predictors of overall survival (P = .0002 and P = .0023, respectively). In conclusion, high-level calretinin expression is most common in grade 3 tumors with a basal-like phenotype and is associated with poor overall survival.

Cadherin-17 and SATB2 are sensitive and specific immunomarkers for medullary carcinoma of the large intestine

CONTEXT

Distinction of medullary carcinoma of the large intestine from other cytokeratin (CK) 7⁻/CK20⁻ carcinomas can be challenging when working on a tumor of unknown primary because the majority of medullary carcinomas are negative for CK7, CK20, and CDX2.

OBJECTIVE

To investigate the expression of cadherin-17 and SATB-2 and other markers in medullary carcinomas of the large intestine and cadherin-17 and SATB2 in a large number of carcinomas and normal tissues from various organs to further test their diagnostic specificity.

DESIGN

This study evaluated cadherin-17 and SATB2 expression in 18 medullary carcinoma cases and 1941 tumors and 358 normal tissues from various organs. Other immunomarkers, including MLH1, PMS2, MSH2, MSH6, CDX2, CK7, CK20, TFF3, MUC4, calretinin, p504S, villin, and synaptophysin, were also tested on the 18 medullary carcinoma cases.

RESULTS

The results demonstrated (1) loss of MLH1 and PMS2 in more than 80% of medullary carcinomas; (2) expression of cadherin-17 and SATB2 in 89% of medullary carcinomas; (3) focal expression of TFF3, MUC4, calretinin, CDX2, CK20, and synaptophysin in 72%, 72%, 67%, 67%, 28%, and 17% of 18 medullary carcinoma cases, respectively; and (4) expression of SATB2 and cadherin-17 in 97% and 98% of the colorectal adenocarcinomas, respectively, whereas their expression was seen in 3.6% and 3.3% of nongastrointestinal tumors, respectively.

CONCLUSION

We concluded that SATB2 and cadherin-17 were highly sensitive and specific markers for colorectal carcinomas and propose including MLH1, cadherin-17, and SATB2 in a routine immunostaining panel when working on a tumor of unknown primary, especially in an elderly patient with a CK7⁻/CK20⁻ carcinoma.

Poorly differentiated medullary carcinoma of the colon with an unusual phenotypic profile mimicking high grade large cell lymphoma - a unique case report and review of the literature

Medullary carcinoma (MC) of the colon and rectum is a rare entity, accounting for less than 0.1% of colonic adenocarcinoma that poses a diagnostic challenge for the practicing pathologist. Poorly differentiated or undifferentiated MC with an unusual histological appearance and immunoprofile in addition to heavy lymphoid infiltrate could make it problematic when differentiating it from a high grade lymphoma, in particular anaplastic large B- or T-cell lymphoma, plasmablastic lymphoma, and other undifferentiated neoplasms. Here we reported a unique case of an 81 y/o woman presenting with a 7.0 cm colon mass detected by computed tomography (CT) scan. A partial transverse and ileum resection with appendectomy were performed. Microscopic examination revealed sheets of large, pleomorphic, mitotically-active cells with abundant eosinophilic cytoplasm and multiple prominent nucleoli, growing with a pushing border and poor glandular formation in a background of intratumoral lymphocytes. The neoplastic cells were only focally positive for keratins (<10%); diffusely and strongly positive for vimentin and CD10 with high proliferative index (Ki-67, 90%). The tumor cells were also aberrantly positive for CD30, CD79a and CD43 (diffusely or focally), resulting in a diagnostic dilemma between colonic MC and high grade lymphoma. Careful examination and additional immunohistochemical stains performed proved there was no evidence of T or B-cell lymphoma, melanoma, or other types of primary colon or metastatic carcinomas. This case highlights the difficulty in distinguishing a high grade lymphoma and poorly differentiated colonic MC, and, also the aberrant expression of CD10 and a significant loss of pancytokeratin could result in a diagnostic pitfall.