CK20 and CK7 protein expression in colorectal cancer: demonstration of the utility of a population-based tissue microarray

Cytokeratin 7 Expression and Mismatch Repair Status for Survival Prediction in Patients With Low Rectal Cancer After Neoadjuvant Therapy

BACKGROUND

More than half of the patients with locally advanced low rectal cancer exhibit no or minor response to nCRT. It is important to investigate the predictive and prognostic values of potential biomarkers in patients with locally advanced low rectal cancer receiving nCRT.

MATERIALS AND METHODS

This retrospective study included 162 patients with locally advanced low rectal cancer who underwent nCRT, followed by total mesorectal excision (TME) between 2016 and 2019. Cytokeratin 7 (CK7) expression and mismatch repair (MMR) status were determined by immunohistochemistry (IHC). Categorical variables were compared using the chi-square test. Overall survival (OS) and disease-free survival (DFS) curves were estimated using the Kaplan-Meier and Cox methods.

RESULTS

There were predominance significant differences in distance from anus margin (P < .0001) and circumferential extent of the tumor (P < .0001).CK7 positive expression was detected in 21 of the 162 patients (13%). The univariate and multivariate analysis revealed that patients whose tumors had CK7 positive expression had significantly shorter OS (HR = 3.878, P = .038; HR = 1.677, P = .035) and DFS (HR = 3.055, P = .027;HR = 3.569, P = .038) than those with CK7 negative expression. While patients with CK7 positive expression had a higher proportion of worse TRG compared with CK7 negative patients (P = .001). Patients with deficient mismatch repair (dMMR) just occupied a small proportion (8.6%), but there was still a close connection between the MMR status and recurrence after TME (P = .045). MMR status was an independent risk factor affecting the OS (HR = .307, P < .0001; HR = .123, P < .0001) and DFS (HR = .288, P < .0001; HR = .286, P < .0001) by univariate and multivariate analysis. But no significant difference in the proportion of TRG was observed between patients with dMMR and pMMR (P = .920).

CONCLUSIONS

The result confirms negative prognostic role of CK7-positive and dMMR statuses, which have potential predictive value for neoadjuvant chemoradiotherapy response. This provides opportunity to modify individualized treatment strategies for patients with different CK7 expression levels and dMMR statuses.

Loss of SATB2 expression correlates with cytokeratin 7 and PD-L1 tumor cell positivity and aggressiveness in colorectal cancer

Colorectal carcinoma (CRC) is a disease that causes significant morbidity and mortality worldwide. To improve treatment, new biomarkers are needed to allow better patient risk stratification in terms of prognosis. This study aimed to clarify the prognostic significance of colonic-specific transcription factor special AT-rich sequence-binding protein 2 (SATB2), cytoskeletal protein cytokeratin 7 (CK7), and immune checkpoint molecule programmed death-ligand 1 (PD-L1). We analyzed a cohort of 285 patients with surgically treated CRC for quantitative associations among the three markers and five traditional prognostic indicators (i.e., tumor stage, histological grade, variant morphology, laterality, and mismatch-repair/MMR status). The results showed that loss of SATB2 expression had significant negative prognostic implications relative to overall survival (OS) and cancer-specific survival (CSS), significantly shortened 5 years OS and CSS and 10 years CSS in patients with CRC expressing CK7, and borderline insignificantly shortened OS in patients with PD-L1 + CRC. PD-L1 showed a significant negative impact in cases with strong expression (membranous staining in 50-100% of tumor cells). Loss of SATB2 was associated with CK7 expression, advanced tumor stage, mucinous or signet ring cell morphology, high grade, right-sided localization but was borderline insignificant relative to PD-L1 expression. CK7 expression was associated with high grade and SATB2 loss. Additionally, a separate analysis of 248 neoadjuvant therapy-naïve cases was performed with mostly similar results. The loss of SATB2 and CK7 expression were significant negative predictors in the multivariate analysis adjusted for associated parameters and patient age. In summary, loss of SATB2 expression and gain of CK7 and strong PD-L1 expression characterize an aggressive phenotype of CRC.

Roles of Keratins in Intestine

Keratins make up a major portion of epithelial intermediate filament proteins. The widely diverse keratins are found in both the small and large intestines. The human intestine mainly expresses keratins 8, 18, 19, and 20. Many of the common roles of keratins are for the integrity and stability of the epithelial cells. The keratins also protect the cells and tissue from stress and are biomarkers for some diseases in the organs. Although an increasing number of studies have been performed regarding keratins, the roles of keratin in the intestine have not yet been fully understood. This review focuses on discussing the roles of keratins in the intestine. Diverse studies utilizing mouse models and samples from patients with intestinal diseases in the search for the association of keratin in intestinal diseases have been summarized.

Cytokeratin 7 and cytokeratin 20 expression in cancer: A tissue microarray study on 15,424 cancers

Combined analysis of cytokeratin 7 (CK7) and cytokeratin 20 (CK20) is often used for assessing the origin of metastatic cancer. To evaluate the diagnostic utility of CK7 and CK20, tissue microarrays containing 15,424 samples from 120 different tumor types and subtypes and 608 samples of 76 different normal tissue types were analyzed by immunohistochemistry. CK7 positivity was seen in 52% (8.7% weak, 5.9% moderate, 37% strong) and CK20 positivity in 23% (5.1% weak, 3.4% moderate, 15% strong) of interpretable tumors. Of 8390 positive tumors, 1181 (14%) showed positivity for CK7 and CK20, 5380 (64%) showed positivity for CK7 alone, and 1829 (22%) showed positivity for CK20 alone. CK20 predominated in gastrointestinal tract, urothelial and Merkel cell carcinomas. CK7 was usually negative in prostate cancer and colorectal cancer. Combined evaluation of CK7/CK20 revealed the best diagnostic utility in CK20 positive tumors, where CK7 negativity is often linked to colorectal origin while CK7 positivity argues for urothelial origin or mucinous ovarian cancer. Associations with unfavorable tumor features were found for cytokeratin 7 loss in breast cancer of no special type, urothelial and renal cell carcinomas, for CK7 overexpression in high-grade serous ovarian and gastric cancer, and for CK20 overexpression in urothelial carcinoma. CK20 loss was linked to MSI in gastric (p = 0.0291) and colorectal adenocarcinoma (p < 0.0001). These analyses provide comprehensive data on the frequency of CK7 and CK20 immunostaining - alone or in combination - in human cancers. These data facilitate interpretation of CK7/CK20 immunostaining in cancers.

Novel Diagnostic Biomarkers in Colorectal Cancer

Colorectal cancer (CRC) is still a leading cause of cancer death worldwide. Less than half of cases are diagnosed when the cancer is locally advanced. CRC is a heterogenous disease associated with a number of genetic or somatic mutations. Diagnostic markers are used for risk stratification and early detection, which might prolong overall survival. Nowadays, the widespread use of semi-invasive endoscopic methods and feacal blood tests characterised by suboptimal accuracy of diagnostic results has led to the detection of cases at later stages. New molecular noninvasive tests based on the detection of CRC alterations seem to be more sensitive and specific then the current methods. Therefore, research aiming at identifying molecular markers, such as DNA, RNA and proteins, would improve survival rates and contribute to the development of personalized medicine. The identification of “ideal” diagnostic biomarkers, having high sensitivity and specificity, being safe, cheap and easy to measure, remains a challenge. The purpose of this review is to discuss recent advances in novel diagnostic biomarkers for tumor tissue, blood and stool samples in CRC patients.

Detection of Marker Associated with CTC in Colorectal Cancer in Mononuclear Cells of Patients with Benign Inflammatory Intestinal Diseases

Simple Summary

Colorectal carcinoma (CRC) is one of the most frequent cancers in western countries, and non-invasive methods for early detection are still needed. Circulating tumor cells (CTC) in blood of CRC patients have been proven as prognostic and predictive biomarker; however, the suitability of CTC-associated markers for early CRC detection and discrimination from benign diseases has not been analyzed. Thus, this study investigated whether CTC-associated markers can also be detected in the blood of patients with benign inflammatory intestinal disease (IID) or whether they are specific for malignancy. The detection rate of CK20 and DEFA5 clearly differed in diseased patients and healthy controls, while LAD1 and PLS3 was found in all samples but with clear qualitative differences in gene expression. No association between inflammation severity and CTC marker expression was found in IID patients. Finally, PLS3 was identified to be a suitable marker for differentiation between malignant and non-malignant intestinal diseases or healthy controls.

Abstract

Colorectal carcinoma (CRC) belongs to the most common tumor entities in western countries. Circulating tumor cells (CTC) in blood of CRC patients are a powerful prognostic and predictive biomarker. However, whether CTC-associated markers can also be used for early CRC detection and discrimination from benign diseases is not known. This study investigated the presence of CTC-associated markers CK20, PLS3, LAD1, and DEFA5 in blood of patients with benign inflammatory intestinal disease (IID) and their correlation with malignancy. The detection rate of CK20 and DEFA5 significantly differed between diseased patients and healthy controls. LAD1 and PLS3 were detected in all samples with clear differences in gene expression. DEFA5 expression was higher in CRC and IID patients compared to healthy donors, while CK20 and PLS3 were lower in CRC compared to IID patients or healthy controls. Overall, all CTC-associated markers were detectable in blood of IID patients, but not correlating with inflammation severity. Finally, PLS3 emerged as a suitable marker for differentiation between malignant and non-malignant intestinal diseases or healthy controls, however its suitability for early CRC detection needs to be further validated.

Novel Therapeutic Strategies for Refractory Ovarian Cancers: Clear Cell and Mucinous Carcinomas

Ovarian cancer has the worst prognosis among gynecological cancers. In particular, clear cell and mucinous carcinomas are less sensitive to chemotherapy. The establishment of new therapies is necessary to improve the treatment outcomes for these carcinomas. In previous clinical studies, chemotherapy with cytotoxic anticancer drugs has failed to demonstrate better treatment outcomes than paclitaxel + carboplatin therapy. In recent years, attention has been focused on treatment with molecular target drugs and immune checkpoint inhibitors that target newly identified biomarkers. The issues that need to be addressed include the most appropriate combination of therapies, identifying patients who may benefit from each therapy, and how results should be incorporated into the standard of care for ovarian clear cell and mucinous carcinomas. In this article, we have reviewed the most promising therapies for ovarian clear cell and mucinous carcinomas, which are regarded as intractable, with an emphasis on therapies currently being investigated in clinical studies.

Cytokeratin 7 expression as a predictor of an unfavorable prognosis in colorectal carcinoma

Colorectal carcinoma (CRC) is associated with significant morbidity and mortality worldwide. Cytokeratins (CKs) are widely expressed in various types of carcinomas, whereas in CRC it is usually CK7 − and CK20 + . A subset of CRCs is CK7 + . This study aims to determine the prevalence of CK7 expression in CRC and its impact on overall survival. We analyzed 300 randomly selected surgically treated CRC cases using paraffin embedded tumor tissue samples and evaluated CK7 and CK20 expression using the tissue microarray method. Tumors with positivity > 10% and > 25% of tumor cells were considered CK7 and CK20 positive, respectively. Expression of both CKs and several clinical-pathological variables (stage, grade, laterality, mismatch-repair/MMR status) were evaluated using patient follow up data (Kaplan–Meier analysis of cancer-specific survival (CSS)). Significant results include shorter CSS (restricted mean 4.98 vs. 7.74 years, P = 0.007) and 5-year survival (29.4% vs. 64.6%, P = 0.0221) in CK7 + tumors compared to CK7 − tumors, respectively; without significant association with grade, stage or right-sided location. These results were significant in a multivariate analysis. CK20 + tumors are more frequently MMR-proficient and left-sided. MMR-deficient tumors are more frequently right-sided and had longer survival. CK7 expression, right-sided location (rmean CSS 6.83 vs. 8.0 years, P = 0.043), MMR-proficiency (rmean CSS 7.41 vs. 9.32 years, P = 0.012), and UICC stages III + IV (rmean CSS 6.03 vs. 8.92 years, P < 0.001) of the tumor correlated with negative prognostic outcomes, whereas the most significant results concern stage and CK7 positivity. The result concerning negative prognostic role of CK7 differs from those obtained by several previous studies focused on this topic.

Keratin intermediate filaments in the colon: guardians of epithelial homeostasis

Keratin intermediate filament proteins are major cytoskeletal components of the mammalian simple layered columnar epithelium in the gastrointestinal tract. Human colon crypt epithelial cells express keratins 18, 19 and 20 as the major type I keratins, and keratin 8 as the type II keratin. Keratin expression patterns vary between species, and mouse colonocytes express keratin 7 as a second type II keratin. Colonic keratin patterns change during cell differentiation, such that K20 increases in the more differentiated crypt cells closer to the central lumen. Keratins provide a structural and mechanical scaffold to support cellular stability, integrity and stress protection in this rapidly regenerating tissue. They participate in central colonocyte processes including barrier function, ion transport, differentiation, proliferation and inflammatory signaling. The cell-specific keratin compositions in different epithelial tissues has allowed for the utilization of keratin-based diagnostic methods. Since the keratin expression pattern in tumors often resembles that in the primary tissue, it can be used to recognize metastases of colonic origin. This review focuses on recent findings on the biological functions of mammalian colon epithelial keratins obtained from pivotal in vivo models. We also discuss the diagnostic value of keratins in chronic colonic disease and known keratin alterations in colon pathologies. This review describes the biochemical properties of keratins and their molecular actions in colonic epithelial cells and highlights diagnostic data in colorectal cancer and inflammatory bowel disease patients, which may facilitate the recognition of disease subtypes and the establishment of personal therapies in the future.

Establishment of an Endoscopy-Guided Minimally Invasive Orthotopic Mouse Model of Colorectal Cancer

Simple Summary

Open orthotopic mouse models of colorectal cancer have disadvantages such as the requirement for advanced surgical skills or the trauma caused by laparotomy. To overcome these limitations, this study aimed to evaluate the establishment of an endoscopy-guided minimally invasive model without laparotomy. Different concentrations of the murine CRC cell lines CT26 and MC38 were endoscopically injected into the colorectal wall of BALB/C and C57BL/6J mice, respectively. Consistent tumor growth with the presence of tumor-infiltrating lymphocytes, lympho-vascular invasion, and early spontaneous lymph node, peritoneal, and hepatic metastases were observed. Analysis of the learning curve demonstrated that this model is easy to learn and quick to establish. It enables intra-individual follow-up endoscopies, and features tumors to study mechanisms of metastasis and the interaction with the immune system. The application of specific cell lines and concentrations enables a controlled local tumor growth and metastatic formation within short observation periods.

Abstract

Open orthotopic mouse models of colorectal cancer have disadvantages such as the requirement for advanced surgical skills or the trauma caused by laparotomy. To overcome these drawbacks, this study aimed to evaluate the establishment of a minimally invasive model using murine colonoscopy. CT26 and MC38 CRC cells of different concentrations were injected into BALB/C and C57BL/6J mice, respectively. Follow-up endoscopies were performed to assign an endoscopic score to tumor growth. Gross autopsy, histologic and immuno-histochemical evaluation, and immune scoring were performed. To describe the learning curve of the procedures, a performance score was given. Local tumor growth with colorectal wall infiltration, luminal ulceration, the presence of tumor-infiltrating lymphocytes, lympho-vascular invasion, and early spontaneous lymph node, peritoneal, and hepatic metastases were observed. The tumors showed cytoplasmic immuno-staining for CK20. Compared to the MC38/C57BL/6J model, tumorigenicity and immunogenicity of the CT26/BALB/C model were higher. Tumor volume correlated with the endoscopic score. This endoscopy-guided orthotopic mouse model is easy to learn and quick to establish. It features early metastasis and enables the study of interactions with the immune system. When specific cell concentrations and cell lines are applied, controlled local tumor growth and metastasis can be achieved within short observation periods.

Endometrium-Limited Metastasis of Extragenital Malignancies: A Challenge in the Diagnosis of Endometrial Curettage Specimens

Malignancies of extragenital origin very rarely metastasize to the uterine body. Endometrium-limited metastases may pose diagnostic challenges in endometrial curettage specimens as they may be misdiagnosed as primary endometrial tumors. We investigated the clinicopathological characteristics of seven cases with endometrial-limited metastases from carcinomas of the nasopharynx (n = 1), breast (n = 2), colon (n = 2), stomach (n = 1), and appendix (n = 1). The patients' ages ranged from 36 to 71 (mean: 55.4) years. None of the patients had a remarkable gynecological history, and the presenting sign in all cases was abnormal uterine bleeding. Although myometrial involvement was absent, multiple metastases were already present in extrauterine locations such as the lung, liver, bone, abdominopelvic peritoneum, and omentum. All patients underwent ultrasonographic examination prior to endometrial curettage. The histologies of the endometrial metastases identified from the curettage specimens were identical to those of the corresponding primary tumors. Ancillary tests including immunostaining and Epstein-Barr virus-encoded RNA in situ hybridization confirmed the extragenital origin. Endometrium-limited metastases from extragenital malignancies are extremely rare. They present with abnormal vaginal bleeding and mimic endometrial carcinomas of endometrioid or poorly differentiated types. Since their clinical presentations and histological features are similar to those of primary endometrial tumors, pathologists should consider the possibility of metastases while evaluating endometrial curettage specimens obtained from patients with a history of extragenital malignancies.

The Emerging Role of Cytoskeletal Proteins as Reliable Biomarkers

Cytoskeletal proteins are essential building blocks of cells. More than 100 cytoskeletal and cytoskeleton-associated proteins are known and for some, their function and regulation are understood in great detail. Apart from cell shape and support, they facilitate many processes such as intracellular signaling and transport, and cancer related processes such as proliferation, migration, and invasion. During the last decade, comparative proteomic studies have identified cytoskeletal proteins as in vitro markers for tumor progression and metastasis. Here, these results are summarized and a number of unrelated studies are highlighted, identifying the same cytoskeletal proteins as potential biomarkers. These findings might indicate that the abundance of these potential markers of tumor progression is associated with the biological outcome and are independent of the cancer origin. This correlates well with recently published results from the Cancer Genome Atlas, indicating that cancers show remarkable similarities in their analyzed molecular information, independent of their organ of origin. It is postulated that the quantification of cytoskeletal proteins in healthy tissues, tumors, in adjacent tissues, and in stroma, is a great source of molecular information, which might not only be used to classify tumors, but more importantly to predict patients' outcome or even best treatment choices.

Cytokeratin 18 regulates the transcription and alternative splicing of apoptotic‑related genes and pathways in HeLa cells

Cytokeratin 18 (CK18), one of the major components of intermediate filaments (IF) in simple epithelial cells, undergoes caspase-mediated cleavage upon epithelial cell necrosis and apoptosis. CK18 has been used as a biomarker of several cancers and has been reported to be dysregulated in cervical cancers. The effects of dysregulated expression of CK18 at a molecular level are, however, unclear. In the present study, the function of CK18 in HeLa cells, a cell line derived from a cervical cancer cells, was investigated using shRNA knockdown. Reduced levels of CK18 led to a significant decrease in cell apoptosis, compared with control cells. Notably, RNA-seq analysis of the transcriptomes of HeLa cells, with or without CK18 knockdown, revealed that genes in the NF-κB pathway, and certain apoptosis pathways, were under global transcriptional and alternative splicing regulation. Quantitative RT-PCR confirmed the CK18-regulated transcription of apoptotic genes FAS and FADD, as well as immune genes CXCL2 and CD79B, in addition to alternative splicing of FAS and CTNNB1. Western blot analysis further revealed that CK18 knockdown led to reduced expression of CASP8. In conclusion, the present study indicated that CK18 played a role in apoptosis, which may be mediated via a feed-back regulation loop and may involve regulation of transcription and alternative splicing of a number of genes in apoptotic pathways.

How the BRAF V600E Mutation Defines a Distinct Subgroup of Colorectal Cancer: Molecular and Clinical Implications

The BRAF oncogene is an integral component of the MAP kinase pathway, and an activating V600E mutation occurs in 15% of sporadic colorectal cancer. This is an early event in serrated pathway tumourigenesis, and the BRAF V600E has been commonly associated with the CpG island methylator phenotype, microsatellite instability (MSI), and a consistent clinical presentation including a proximal location and predilection for elderly females. A proportion of the BRAF mutant lesions remain as microsatellite stable (MSS), and in contrast to the MSI cancers, they have an aggressive phenotype and correlate with poor patient outcomes. Recent studies have found that they have clinical and molecular features of both the BRAF mutant/MSI and the conventional BRAF wild-type cancers and comprise a distinct colorectal cancer subgroup. This review highlights the importance of the BRAF mutation occurring in colorectal cancer stratified for molecular background and discusses its prognostic and clinical significance.

Nitrofurantoin Toxicity: A Near Case of Mistaken Identity

Nitrofurantoin is one of the most utilized antibiotics to treat bladder and urinary tract infections (UTIs). Despite the clinical benefits, it requires vigilant monitoring, as it can cause damage to multiple organs, especially the lungs and the liver. This case is an example of clinical vigilance, which provided tremendous benefit for the patient.

Improving diagnosis, prognosis and prediction by using biomarkers in CRC patients (Review)

Colorectal cancer (CRC) is among the most common cancers. In fact, it is placed in the third place among the most diagnosed cancer in men, after lung and prostate cancer, and in the second one for the most diagnosed cancer in women, following breast cancer. Moreover, its high mortality rates classifies it among the leading causes of cancer‑related death worldwide. Thus, in order to help clinicians to optimize their practice, it is crucial to introduce more effective tools that will improve not only early diagnosis, but also prediction of the most likely progression of the disease and response to chemotherapy. In that way, they will be able to decrease both morbidity and mortality of their patients. In accordance with that, colon cancer research has described numerous biomarkers for diagnostic, prognostic and predictive purposes that either alone or as part of a panel would help improve patient's clinical management. This review aims to describe the most accepted biomarkers among those proposed for use in CRC divided based on the clinical specimen that is examined (tissue, faeces or blood) along with their restrictions. Lastly, new insight in CRC monitoring will be discussed presenting promising emerging biomarkers (telomerase activity, telomere length and micronuclei frequency).

Dual Stain With SATB2 and CK20/Villin Is Useful to Distinguish Colorectal Carcinomas From Other Tumors

OBJECTIVES

Small sample size limits the number of immunostains that may be attempted in colorectal carcinoma (CRC) biopsy specimens. We investigated the utility of dual stain with special AT-rich sequence binding protein 2 (SATB2) or caudal-type homeobox 2 (CDX2) and cytokeratin 20 (CK20) or villin in identifying CRC.

METHODS

Tissue microarrays with 222 CRCs and 375 other carcinomas were built. Dual stain was performed pairing nuclear stains CDX2 or SATB2 with CK20 or villin.

RESULTS

All four single stains showed excellent sensitivity (93%-99%) but variable specificity (56%-88%) for CRC. All four dual stains also showed excellent sensitivity (90%-96%) while much improved specificity (88%-98%) compared with single stains. SATB2 dual stain (with CK20 or villin) showed a higher specificity than CDX2 dual stain (with CK20 or villin) with a comparable sensitivity.

CONCLUSIONS

SATB2 dual stain shows the greatest potential clinical utility in identifying CRC and is superior to CDX2 dual stain. More important, SATB2 dual stain could be helpful for specimens with limited tissues or those having a nonclassic staining pattern.

Immunohistochemical staining of cytokeratin 20 and cytokeratin 7 in colorectal carcinomas: Four different immunostaining profiles

BACKGROUND/AIM

Aberrant expression of CK20/CK7 is reported in a percentage of colorectal carcinomas (CRC); however, its relation to clinicopathological variables and survival data is still unclear. The objective of this study is to explore patterns of CK20/CK7 immunostaining in CRC and to analyse the diagnostic, prognostic, and predictive role of patterns of CK20/CK7 immunostaining.

MATERIALS AND METHODS

A total of 144 CRC cases were retrieved from the archives at the Department of Pathology, King Abdulaziz University, Jeddah, Saudi Arabia. Immunohistochemistry was performed using antibody to CK7 and CK20. Immunostaining was defined as low and high by using the extent of staining. The association of CK7 and CK20 with clinicopathological characteristics and survival.

RESULTS

CK20 was expressed in a higher percentage of CRC and nodal metastasis than CK7. No difference in CK7 and CK20 immunostaining in primary and metastasis carcinomas was found. Four patterns of CK20/CK7 were identified; CK20+/CK7- (60.4%), CK20+/CK7+ (2.1%), CK20-/CK7- (35.4%), and CK20-/CK7+ (2.1%). There was no statistically significant correlation between CK20/CK7 immunohistochemical profile and clinicopathological characteristics, prognosis, and survival was determined.

CONCLUSIONS

Our results may support the heterogeneity of CRC. CRC showed four different subclasses following patterns of relative CK20/CK7 immunostaining. A considerable number of CRC expressed aberrant immune profile of CK20/CK7, which should be considered during diagnosing CRC in metastatic regions. Further studies on larger cohorts correlating different immunohistochemical cytokeratin profiles to molecular subtypes of CRC are recommended for better understanding of pathogenesis and behaviour of CRC.

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.

Efficacy of Immunohistochemical Staining in Differentiating a Squamous Cell Carcinoma in Poorly Differentiated Rectal Cancer: Two Case Reports

A rectal carcinoma, including primary an adenosquamous and a squamous cell carcinoma (SCC), is a very rare disease, accounting for 0.025% to 0.20% of all large-bowel malignant tumors. Because SCCs have a higher mortality than adenosquamous carcinomas, determining whether the primary rectal cancer exhibits an adenomatous component or a squamous component is important. While differentiating between these 2 components, especially in poorly differentiated rectal cancer, is difficult, specific immunohistochemical stains enable accurate diagnoses. Here, we report the use of immunohistochemical stains to distinguish between the adenomatous and the squamous components in 2 patients with low rectal cancer, a 58-year-old man and a 73-year-old woman, who were initially diagnosed using the histopathologic results for a poorly differentiated carcinoma. These data suggest that using these immunohistochemical stains will help to accurately diagnose the type of rectal cancer, especially for poorly differentiated carcinomas, and will provide important information to determine the proper treatment for the patient.

Radioprotection of 1,2-dimethylhydrazine-initiated colon cancer in rats using low-dose γ rays by modulating multidrug resistance-1, cytokeratin 20, and β-catenin expression

Ionizing radiation is a widely used therapy for solid tumors. However, high-dose ionizing radiation causes apoptosis, transforms normal cells into tumor cells, and impairs immune functions, leading to the defects in the removal of damaged or tumor cells. In contrast, low-dose radiation has been reported to exert various beneficial effects in cells. This experimental study investigated the effect of γ rays at low dose on the development of colorectal tumor in a 1,2-dimethylhydrazine (DMH)-induced colon cancer. Colorectal tumor model was induced in Wistar rats by subcutaneous injection of DMH (20 mg/kg) once a week for 15 weeks. Starting from zero day of DMH injection, a single low dose of whole-body γ irradiation of 0.5 Gy/week was applied to the rats. A significant reduction in lipid peroxidation, nitric oxide, and elevation in the glutathione content and antioxidant enzyme activity (superoxide dismutase and catalase) were observed after γ irradiation comparing with DMH group. Moreover, γ ray reduced the expressions of multidrug resistance 1 (MDR1), β-catenin, and cytokeratin 20 (CK20) those increased in DMH-treated rats. However, survivin did not change with γ ray treatment. A histopathological examination of the DMH-injected rats revealed ulcerative colitis, dysplasia, anaplasia, and hyperchromasia. An improvement in the histopathological picture was seen in the colon of rats exposed to γ rays. In conclusion, the present results showed that low-dose γ ray significantly inhibited DMH-induced colon carcinogenesis in rats by modulating CK20, MDR1, and β-catenin expression but not survivin expression.

Infrared imaging of primary melanomas reveals hints of regional and distant metastases

Melanoma is the deadliest form of skin cancer. Metastatic melanomas are resistant to almost all existing adjuvant therapies such as chemotherapy and radiotherapy, so detection of metastases remains a challenge, and no biomarkers are currently available to detect primary tumors with the highest risk of metastasis. Results presented in this paper show that Fourier Transform Infrared (FTIR) imaging of histological sections followed by supervised partial least squares discriminant analysis (PLS-DA) can accurately (>90%) identify the main cell types commonly found in melanoma tumors. Here we define six cell types: melanoma cells, erythrocytes, connective tissue (includes blood vessel walls, dermis and collagen regions), keratinocytes, lymphocytes and necrotic cells. Interestingly, more than 98% of the melanoma cells are correctly identified. The spectra of the cells identified as melanomas were then further analyzed. First, we compared melanoma cells in primary tumors (from 26 patients) with melanoma cells from metastases (from 25 patients). Neither supervised nor unsupervised analyses revealed any significant difference. Similarly, we found no significant correlation between the infrared spectra of melanoma cells and the number of proliferative cells assessed by Ki67 immunostaining. Finally, we compared the infrared spectra of primary tumors from patients diagnosed at different stages of the disease. Infrared spectroscopy was capable of pointing out differences between primary tumors of patients at stage I or II and patients at stage III or IV, even by unsupervised analysis. We then developed a supervised PLS-DA model capable of predicting whether tumor cells belonged to one of the two aggregated disease stage groups. The model predicted a high rate of true positives (sensitivity of 88.9%) and a good rate of true negatives (specificity of 70.6%) in external validation. These results demonstrate that infrared spectroscopy can be used to help identify melanoma characteristics related to the cells' invasive capability.

SEER cancer registry biospecimen research: yesterday and tomorrow

The National Cancer Institute's (NCI) Surveillance, Epidemiology, and End Results (SEER) registries have been a source of biospecimens for cancer research for decades. Recently, registry-based biospecimen studies have become more practical, with the expansion of electronic networks for pathology and medical record reporting. Formalin-fixed paraffin-embedded specimens are now used for next-generation sequencing and other molecular techniques. These developments create new opportunities for SEER biospecimen research. We evaluated 31 research articles published during 2005 to 2013 based on authors' confirmation that these studies involved linkage of SEER data to biospecimens. Rather than providing an exhaustive review of all possible articles, our intent was to indicate the breadth of research made possible by such a resource. We also summarize responses to a 2012 questionnaire that was broadly distributed to the NCI intra- and extramural biospecimen research community. This included responses from 30 investigators who had used SEER biospecimens in their research. The survey was not intended to be a systematic sample, but instead to provide anecdotal insight on strengths, limitations, and the future of SEER biospecimen research. Identified strengths of this research resource include biospecimen availability, cost, and annotation of data, including demographic information, stage, and survival. Shortcomings include limited annotation of clinical attributes such as detailed chemotherapy history and recurrence, and timeliness of turnaround following biospecimen requests. A review of selected SEER biospecimen articles, investigator feedback, and technological advances reinforced our view that SEER biospecimen resources should be developed. This would advance cancer biology, etiology, and personalized therapy research. See all the articles in this CEBP Focus section, "Biomarkers, Biospecimens, and New Technologies in Molecular Epidemiology." Cancer Epidemiol Biomarkers Prev; 23(12); 2681-7. ©2014 AACR.

Cytokeratins in gastroenterology. Systematic review

Keratins are proteins that form intermediate filaments of epithelial cell cytoskeleton. The utility of keratin expression determination is based on the fact that epithelial cells acquire a specific pattern of keratin expression during differentiation and maturation, which reflects the specificity of the tissue and the degree of maturation, and generally remains stable during carcinogenesis. Determination of the pattern makes it possible to identify the origin of cells in diagnosing neoplastic lesions as well as in research on pathophysiology or the possibility to apply keratin-positive cell detection in the process of cancer staging and treatment planning. As keratins undergo degradation during apoptosis as caspase substrate the identification of the caspase-derived K18 fragment by the use of specific monoclonal antibody allows us to estimate the apoptosis/necrosis ratio, especially in liver pathology, e.g. nonalcoholic steatohepatitis, chronic hepatitis or graft-versus-host disease or in assessing response to antiviral or antitumour therapy.

Establishment and characterization of a cell line from human circulating colon cancer cells

Circulating tumor cells (CTC) in blood are promising new biomarkers potentially useful for prognostic prediction and monitoring of therapies in patients with solid tumors including colon cancer. Moreover, CTC research opens a new avenue for understanding the biology of metastasis in patients with cancer. However, an in-depth investigation of CTCs is hampered by the very low number of these cells, especially in the blood of patients with colorectal cancer. Thus, the establishment of cell cultures and permanent cell lines from CTCs has become the most challenging task over the past year. Here, we describe, for the first time, the establishment of cell cultures and a permanent cell line from CTCs of one patient with colon cancer. The cell line designated CTC-MCC-41 has been cultured for more than one year, and the cells have been characterized at the genome, transcriptome, proteome, and secretome levels. This thorough analysis showed that CTC-MCC-41 cells resemble characteristics of the original tumor cells in the patient with colon cancer and display a stable phenotype characterized by an intermediate epithelial/mesenchymal phenotype, stem cell-like properties, and an osteomimetic signature, indicating a bone marrow origin. Functional studies showed that CTC-MCC-41 cells induced rapidly in vitro endothelial cell tube formation and in vivo tumors after xenografting in immunodeficient mice. The establishment of this first colon cancer CTC line allows now a wealth of functional studies on the biology of CTCs as well as in vitro and in vivo drug testing.

The role of SATB2 as a diagnostic marker for tumors of colorectal origin: Results of a pathology-based clinical prospective study

OBJECTIVES

Immunohistochemistry is an important extension to clinical information and morphology, and prevails as an invaluable tool for establishing a correct cancer diagnosis in clinical diagnostic pathology. The applicability of immunohistochemistry is limited by the availability of validated cell- and cancer-type specific antibodies, rendering an unmet need to discover, test, and validate novel markers. The SATB2 protein is selectively expressed in glandular cells from the lower gastrointestinal tract and expression is retained in a large majority of primary and metastatic colorectal cancers.

METHODS

We analyzed the expression of SATB2 in all clinical cases (n = 840), in which immunohistochemistry for detection of CK20 was deemed necessary for a final diagnosis.

RESULTS

SATB2 showed a high sensitivity (93%) and specificity (77%) to determine a cancer of colorectal origin and in combination with CK7 and CK20, the specificity increased to 100%.

CONCLUSIONS

We conclude that SATB2 provides a new and advantageous supplement for clinical differential diagnostics.

Improving colorectal cancer management: the potential of proteomics

Colorectal cancer (CRC) is the third most common cancer worldwide. Successful treatment is heavily dependent on tumor stage at the time of detection, but unfortunately CRC is often only detected in advanced stages. New biomarkers in the form of genes or proteins that can be used for diagnosis, prognostication, follow-up, and treatment selection and monitoring could be of great benefit for the management of CRC. Furthermore, proteins could prove valuable new targets for therapy. Therefore, clinical proteomics has gained a lot of scientific interest in this regard. To get an overall insight into the extent to which this research has contributed to a better management of CRC, we give a comprehensive overview of the results of proteomics research on CRC, focusing on expression proteomics, in other words, protein profiling studies. Furthermore, we evaluate the potential of the discriminating proteins identified in this research for clinical use as biomarkers for (early) diagnosis, prognosis and follow-up of CRC or as targets for new therapeutic regimens.

Construction of a tissue microarray with two millimeters cores of endometrioid endometrial cancer: factors affecting the quality of the recipient block

The tissue microarray (TMA) method currently is not used to render a primary diagnosis of cancer, but its scientific value has been proved in studies of various cancer types. TMA technology still is not used often for uterine tumors, however. We investigated the repeatability of histological diagnosis of endometrioid endometrial cancer (EEC) using conventional histology and TMA using 2 mm cores. We examined EEC tissues from 171 patients. Formalin fixed, paraffin embedded tissue donor blocks from EEC specimens were selected and examined histologically. Duplicate 2 mm tissue cores were inserted into a TMA recipient block. EEC tissues were examined as hematoxylin-eosin stained sections from the TMAs. EEC tissue was identified in the TMAs in 158 cases (92.4%) and not found in 13 cases (7.6%). On the TMA slides, both EEC positive cores were identified in 129 cases (75.4%), but only one core in 29 cases (17.0%). Among 342 biopsies of the donor blocks (each case in duplicate), EEC was found in 287 cases (83.9%) using the TMA: 124/146 (84.9%) with superficial infiltration, 153/178 (86.0%) with deep myometrial infiltration, and 10/18 (55.6%) without myometrial infiltration. We concluded that two 2 mm tissue cores from a biopsy of a donor block inserted into a TMA recipient block were sufficient to diagnose EEC in more than 90% of cases. EEC was identified in the TMAs with similar frequency with respect to superficial and deep myometrial infiltration. Cases without myometrial infiltration were identified less often.

Aberrant pattern of the cytokeratin 7/cytokeratin 20 immunophenotype in colorectal adenocarcinomas with BRAF mutations

Cytokeratin 7 (CK7) and 20 (CK20) are used for the differential diagnosis of metastases from colorectal carcinomas (CRC), which are usually CK7-/CK20+, and other tumors. In our study, we performed immunohistochemical staining with CK7 and CK20 in 52 randomly selected cases of CRC and analyzed microsatellite instability status and BRAF mutations to identify those factors that may determine the changing pattern of CK7/CK20 immunophenotype in these tumors. CK7 was negative in all microsatellite stable tumors (MSS), but all carcinomas presenting microsatellite instability (MSI) and BRAF mutations were diffusely positive for this marker. CK20 was diffusely expressed in 79.06% of MSS tumors. Regarding MSI, in case with no BRAF mutations, a progressive decrease in CK20 expression was noted, and in BRAF-mutated adenocarcinomas, no expression of CK20 was observed. It seems that in case of MSI located on the proximal colon, which also presents BRAF mutations, CK20/CK7 may present a changing immunophenotype pattern, which may complicate the differential diagnosis of metastatic tumors. This is the first reported study of the relationship between CK20/CK7 immunophenotype, BRAF mutations and microsatellite status in CRC.

The value of CDX2 and cytokeratins 7 and 20 expression in differentiating colorectal adenocarcinomas from extraintestinal gastrointestinal adenocarcinomas: cytokeratin 7-/20+ phenotype is more specific than CDX2 antibody

Background/Objective

Metastatic adenocarcinoma from an unknown primary site is a common clinical problem. Determining the cytokeratin (CK) 7/CK20 pattern of tumors is one of the most helpful procedures for this purpose since the CK7-/CK20+ pattern is typical of colorectal adenocarcinomas. CDX2, a critical nuclear transcription factor for intestinal development, is expressed in intestinal epithelium and adenocarcinomas. In the present study, we compared the sensitivity and specificity of CDX2 expression and the CK7-/CK20+ phenotype in differentiating colorectal adenocarcinomas from pancreatic and gastric adenocarcinomas.

Methods

CK7/CK20 staining pattern and CDX2 expression were evaluated in 118 cases of colorectal, 59 cases of gastric, and 32 cases of pancreatic adenocarcinomas. The sensitivity, specificity, and positive and negative predictive values of the CK7-/CK20+ phenotype and of CDX2 expression were analyzed.

Results

The CK7-/CK20+ immunophenotype was expressed by 75 of 118 (64%) colorectal and 3 of 59 (5%) gastric tumors and was not observed in any pancreatic adenocarcinomas. The CK7+/CK20+ immunophenotype was expressed in 24/118 (20%) of colon, 28/59 (48%) of gastric and 7/32 (22%) of pancreatic adenocarcinomas. The CK7+/CK20- expression pattern was observed in only 2% (2 of 118) of colorectal carcinomas. CDX2 was expressed in 114 of 118 (97%) colorectal, 36 of 59 (61%) gastric, and 5 of 32(16%) pancreatic adenocarcinomas. There was no significant association between CDX2 expression and tumor differentiation in colorectal carcinomas. In gastric carcinomas, CDX2 expression was more common in intestinal type tumors than in diffuse type carcinomas. The CK7-/CK20+ phenotype showed a specificity of 96.7% in predicting colorectal adenocarcinomas, which was superior to that of CDX2 expression. CDX2 expression at both cut-off levels (> 5% and > 50%) had a higher sensitivity (96.6% and 78%) than the CK phenotype.

Conclusions

Both the CK7-/CK20+ phenotype and expression of the antibody CDX2 are highly specific and sensitive markers of colorectal origin. CDX2 expression should be a useful adjunct for the diagnosis of intestinal adenocarcinomas, particularly when better established markers such as CK7 and CK20 yield equivocal results. The CK7-/CK20+ phenotype is superior in its specificity and positive predictive value and might be preferred.

Virtual slides

The virtual slide(s) for this article can be found here:

http://www.diagnosticpathology.diagnomx.eu/vs/4851011866354821

Keratin 7 expression in colorectal cancer--freak of nature or significant finding?

AIMS

 To assess the prevalence of keratin 7 (K7) expression in colorectal cancer and to correlate findings with clinicopathological parameters and patients' outcome.

METHOD AND RESULTS

A total of 370 patients were evaluated for K7 expression by immunohistochemistry using a tissue microarray technique. K7 expression was scored semiquantitatively as either focal (<10%), moderate (10-50%) or extensive (>50%). In all, 32 (9%) tumours were immunoreactive for K7, with five cases showing extensive, four moderate and 23 focal expression, respectively. K7 expression was associated with poor tumour differentiation (P = 0.005) and the extent of tumour budding (P = 0.02). In whole sections, K7 immunoreactivity prevailed in single cells and small clusters of cells at the invasion front. Analysis of serial sections showed that K7-positive cells colocalized with keratin 20, whereas they lacked immunoreactivity for E-cadherin, MUC2 and MIB-1. Disease progression occurred in 52% of patients with K7-positive tumours and 41% with K7-negative tumours (P = 0.19); 48% of patients with K7-positive tumours but only 33% with K7-negative tumours died of disease (P = 0.06).

CONCLUSIONS

Aberrant expression of K7 in budding cancer cells represents a modification of the epithelial phenotype ('epithelial-epithelial transition': EET) which may be linked to gains in motility and invasive potential.

Mucinous carcinomas of the ovary and colorectum: different organ, same dilemma

Mucinous carcinomas are uncommon histological types that affect several organ sites. Primary mucinous carcinomas of the ovary are distinct from other ovarian carcinoma types, but they can pose a particular challenge for correct diagnosis from metastases, which most usually originate from the colorectum. Correct diagnosis is the mainstay of treatment, because standard practice states that protocols are tailored to the primary organ site. Little is known of mutational alterations in primary and metastatic mucinous carcinomas of the ovary, and few markers exist that can discriminate between them. We reviewed commonalities between ovarian and colorectal mucinous carcinomas with respect to aetiology, molecular alterations, differential diagnosis, and implications for treatment. Although primary mucinous carcinomas of the ovary and colorectum share similar mutational patterns and unfavourable outcomes at advanced stage, compared with their non-mucinous counterparts, important differences exist with respect to mucin localisation and specific molecular alterations. Technologies--eg, next-generation sequencing--could aid identification of additional driver molecular changes that will help clarify the relation between mucinous carcinomas from different organ sites. Perhaps, then, we can consider moving towards testing and adoption of therapeutic approaches tailored to molecular characteristics of mucinous carcinomas, irrespective of organ site, so patients' survival can be optimised.

Cytokeratin 7 and cytokeratin 20 expression in colorectal adenocarcinomas

Cytokeratin 7 (CK7) and cytokeratin 20 (CK20) are low molecular weight cytokeratins. The expressions of CK7 and CK20 have been studied in various primary and metastatic carcinomas. Their expression patterns may help to distinguish the site of origin of metastatic carcinomas. We investigated the expressions of CK7 and CK20 in 196 cases of colorectal carcinoma. Paraffin sections of 196 colonic adenocarcinomas were randomly selected, retrieved, and immunostained for CK7 and CK20 with a standard avidin-biotin complex method. CK7 was expressed in 34/196 (17.3%) and CK20 in 159/196 (81.1) cases of colorectal adenocarcinoma. CK7-/CK20+ had the greatest proportion (65.8%) in colorectal carcinomas. The CK7+/CK20+ immunophenotype was identified in 30/196 (15.3%), CK7-/CK20- in 33/196 (16.9%), and CK7+/CK20- in 4/196 (2%) colon adenocarcinomas. The CK7 and CK20 expression patterns were different in colorectal carcinomas according to histological grade, location of the tumor, and lymph node metastasis. CK20 positivity was more common in low grade carcinomas than in high grade carcinomas (85.1% versus 47.6%) and in rectal and sigmoid carcinomas than in proximal colon carcinomas (88.2% versus 63.2% and 88.9% versus 63.2%, respectively). Furthermore, CK7 expression was more common in tumors with lymph node metastasis than in non-metastatic tumors (25.3% versus 11%). In conclusion, a considerable number of colorectal carcinomas showed reactivity to CK7 (17.3%) or no reactivity to CK20 (18.9%). Therefore, CK7 positivity or CK20 negativity does not rule out a colorectal origin of metastatic carcinoma.

Differences of immunophenotypic markers and signaling molecules between adenocarcinomas of gastric cardia and distal stomach

During the past decades, the subsites of gastric carcinoma underwent significant changes. The incidence of the adenocarcinoma at distal stomach has been decreased, whereas cardiac adenocarcinoma remained increasing in many countries. The aim of this study was to investigate the differences between gastric cardiac and distal adenocarcinomas. We detected expressions of cytokeratins (cytokeratins 7, 14, 19, and 20) and mucins (mucins 1, 2, and 5AC) by immunohistochemistry and signaling molecules (p38, mitogen-activated protein kinase-interacting kinase 1 (MNK1), extracellular signal-regulated kinase, Jun N-terminal kinase, and phosphoinositide 3 kinase) by reverse transcription-polymerase chain reaction in both groups. The incidence of mucin 2 expression was lower in total (50.0%) and advanced-stage cases (52.0%) with cardiac adenocarcinomas than those in distal cases with total (70.2%) and advanced stage (71.4%), respectively. However, the staining for cytokeratin 14 was also significantly higher in total or advanced-stage tumors from the cardia. Our data showed no significant difference of cytokeratin 7/cytokeratin 20 pattern between 2 groups, but cytokeratin 20 expression was significantly higher in advanced-stage carcinomas of the cardia (58.7%) than in distal ones with advanced stage (38.3%). A multivariate analysis demonstrated different relationships between immunophenotypic markers and pathologic parameters in adenocarcinomas of the cardia and distal stomach. Moreover, significantly lower expressions of MNK1 and p38 in cardiac tumors were also detected. In summary, we found significant differences in patterns of immunophenotypic markers and expressions of signaling molecules between the 2 groups. It is indicated that adenocarcinoma of the cardia was different in histotype and histologic origin from distal adenocarcinoma. The cardiac adenocarcinoma might be a special subtype or an independent entity of gastric carcinoma in China.

Toponome imaging system: in situ protein network mapping in normal and cancerous colon from the same patient reveals more than five-thousand cancer specific protein clusters and their subcellular annotation by using a three symbol code

In a proof of principle study, we have applied an automated fluorescence toponome imaging system (TIS) to examine whether TIS can find protein network structures, distinguishing cancerous from normal colon tissue present in a surgical sample from the same patient. By using a three symbol code and a power of combinatorial molecular discrimination (PCMD) of 2(21) per subcellular data point in one single tissue section, we demonstrate an in situ protein network structure, visualized as a mosaic of 6813 protein clusters (combinatorial molecular phenotype or CMPs), in the cancerous part of the colon. By contrast, in the histologically normal colon, TIS identifies nearly 5 times the number of protein clusters as compared to the cancerous part (32 009). By subcellular visualization procedures, we found that many cell surface membrane molecules were closely associated with the cell cytoskeleton as unique CMPs in the normal part of the colon, while the same molecules were disassembled in the cancerous part, suggesting the presence of dysfunctional cytoskeleton-membrane complexes. As expected, glandular and stromal cell signatures were found, but interestingly also found were potentially TIS signatures identifying a very restricted subset of cells expressing several putative stem cell markers, all restricted to the cancerous tissue. The detection of these signatures is based on the extreme searching depth, high degree of dimensionality, and subcellular resolution capacity of TIS. These findings provide the technological rationale for the feasibility of a complete colon cancer toponome to be established by massive parallel high throughput/high content TIS mapping.

Keratins in health and cancer: more than mere epithelial cell markers

Keratins are the intermediate filament (IF)-forming proteins of epithelial cells. Since their initial characterization almost 30 years ago, the total number of mammalian keratins has increased to 54, including 28 type I and 26 type II keratins. Keratins are obligate heteropolymers and, similarly to other IFs, they contain a dimeric central α-helical rod domain that is flanked by non-helical head and tail domains. The 10-nm keratin filaments participate in the formation of a proteinaceous structural framework within the cellular cytoplasm and, as such, serve an important role in epithelial cell protection from mechanical and non-mechanical stressors, a property extensively substantiated by the discovery of human keratin mutations predisposing to tissue-specific injury and by studies in keratin knockout and transgenic mice. More recently, keratins have also been recognized as regulators of other cellular properties and functions, including apico-basal polarization, motility, cell size, protein synthesis and membrane traffic and signaling. In cancer, keratins are extensively used as diagnostic tumor markers, as epithelial malignancies largely maintain the specific keratin patterns associated with their respective cells of origin, and, in many occasions, full-length or cleaved keratin expression (or lack there of) in tumors and/or peripheral blood carries prognostic significance for cancer patients. Quite intriguingly, several studies have provided evidence for active keratin involvement in cancer cell invasion and metastasis, as well as in treatment responsiveness, and have set the foundation for further exploration of the role of keratins as multifunctional regulators of epithelial tumorigenesis.

Isolation and propagation of a human CD133(-) colon tumor-derived cell line with tumorigenic and angiogenic properties

It has been proposed in human colorectal cancers (CRC) a minority subset of cancer cells within tumors able to initiate tumor growth, defined as cancer stem cells (CSC). Solid human primary colonic and its ovarian metastatic cancer tissues were collected from fresh surgical samples and subsequent xenografts were established in nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice. The resulting tumors were disaggregated into single-cell suspensions and a CD133(-) cell line (NANK) was newly established and analyzed by flow cytometry. Surface markers of progenitor cells were immunophenotypically analyzed, and expression of stem cell and cancer-related genes was characterized. Secreted angiogenesis-associated molecules were investigated by proteomic array technology. Finally, different numbers of NANK were implanted and their tumor-initiating properties were investigated in NOD/SCID mice. Intraperitoneal injection of NANK in NOD/SCID mice induced tumors with developing progressive peritoneal dissemination and ascites. NANK cells maintained a differentiated phenotype and reproduced the full morphologic and phenotypic heterogeneity of their parental lesions. Noticeably, NANK lacked the expression of conventional CSC markers CD133 and CD44, self-renewal genes Oct-4 and Nanog, but showed the expression of an important gastrointestinal development marker CDX-2 and BMI-1 that is essential in regulating the proliferative activity of normal and leukemic stem cells. In addition, NANK secreted high amounts of important angiogenic cytokines. These results provide a novel and extensive model in human CSC for studying the generation and maintenance of phenotypic heterogeneity in CRC.

The alphavbeta6 integrin is a highly specific immunohistochemical marker for cholangiocarcinoma

BACKGROUND & AIMS

Hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC) are common primary hepatic malignancies. Their immunohistological differentiation using specific markers is pivotal for treatment and prognosis. We found alphavbeta6 integrin strongly upregulated in biliary fibrosis, but its expression in primary and secondary liver tumours is unknown. Here, we aimed to evaluate the diagnostic applicability of alphavbeta6 integrin in differentiating primary liver cancers.

METHODS

Expression of alphavbeta6 integrin was evaluated in liver tissues from patients with CC, HCC, fibrolamellar HCC, combined CC/HCC, hepatic metastases of colorectal and pancreatic carcinomas, primary sclerosing cholangitis (PSC), and in human primary and tumour-derived liver cell lines by immunohisto- and cytochemistry, and by TaqMan PCR. Diagnostic performance of the beta6 subunit was compared with CK7, CK20, and HepPar 1.

RESULTS

In CC cells beta6 mRNA levels were induced 125-fold compared to primary cholangiocytes, while it was completely absent in hepatoma cells. In human tissues, beta6 transcripts were more than 100-fold upregulated in CC compared to normal liver. By immunohistochemistry, 88% of CC, 50% of PSC, 13% of colorectal carcinoma metastases, and 80% of pancreatic carcinoma metastases presented alphavbeta6, whereas all HCC, combined CC/HCC and fibrolamellar HCC stained negative. Specificity of beta6 immunohistochemistry for CC (100%) surpassed all other tested markers and sensitivity was equal to CK7 (86% vs. 90%).

CONCLUSION

The alphavbeta6 integrin is strongly expressed in human CC but not in HCC and therefore can be considered as a specific immunohistochemical marker in the differential diagnosis of primary liver tumours.

Mammographic density and matrix metalloproteinases in breast tissue

Mammographic density is a strong risk factor for breast cancer, yet the underlying histopathologic correlates are not clear. Matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) play important roles in multiple stages of tumorigenesis. This study examined the association between mammographic density and expression of MMPs 1, 3, 9, and 12 and TIMP3 in benign and malignant breast tissue of 277 women with mainly Caucasian and Japanese ancestry. Tissue microarrays with up to 4 benign and 4 malignant cores per woman were stained immunohistochemically and evaluated. Digitized prediagnostic mammograms were assessed for densities using a computer-assisted method. General linear models adjusted for known confounders were applied to estimate mean densities by staining category. Strong expression of all MMPs was about twice as frequent in malignant as in benign tissue, while TIMP3 expression in stromal tissue was higher in benign than malignant cores. For MMP3 and 9, less than 10% of cores stained positive; thus, they were not further analyzed. None of the markers showed a statistically significant association with breast density in the entire study population and ethnic-specific results were conflicting and difficult to explain. Although not statistically significant, mean density was consistently lower with more extensive TIMP3 expression in stromal and epithelial tissue. These findings indicate that the higher breast cancer risk in women with dense breasts may be influenced by lower TIMP3 expression. However, future investigations into activities and ratios of additional proteases and their inhibitors as well as other pathways, such as inflammation, are needed.

CDX2, cytokeratins 7 and 20 immunoreactivity in rectal adenocarcinoma

There are limited data regarding CDX2 expression in rectal carcinoma. The CK20/CK7 immunoprofile of colorectal adenocarcinoma has been described in studies, which have mostly lumped colonic and rectal tumors together. In this study, we investigated the diagnostic utility of immunohistochemical stains for CK7, CK20, and CDX2 in a series of rectal adenocarcinoma. Fifty-five specimens of rectal adenocarcinomas were retrieved and immunostained for CK7 (Dako-M7018), CK20 (NovoCastra NCL-L-CK20), and CDX2 (NovoCastra NCL-CDX2). Thirty cases of pancreatic adenocarcinoma and 15 cholangiocarcinomas were also studied as a comparison group. CK7 was expressed in 12/55 (22%) and CK20 in 48/55 (87%) cases of rectal adenocarcinoma. The CK7-/CK20+ immunophenotype was identified in 36/55 (65%), CK7+/CK20+ in 12/55 (22%), and CK7-/CK20- in 7/55 (13%) rectal adenocarcinoma. CDX2 showed moderate-strong positivity in all cases and was not related to tumor differentiation. Benign rectal mucosa was available in 37 cases and showed the following results: CK7-/CK20+ in 25/37 (67%), CK7+/CK20+ in 8/37 (22%) and CK7-/CK20- in 4/37 (11%) cases. In pancreatic adenocarcinomas and cholangiocarcinomas, 29/45 (64%) were CK7+/CK20+ and 16/45 (36%) were CK7+/CK20-. CDX2 was positive in only 3/45 (7%) of these cases; all were pancreatic adenocarcinomas. In conclusion, CK7 can be expressed in rectal adenocarcinoma, and should not be used as the sole basis for excluding a rectal primary. CDX2 is a sensitive marker for rectal origin of adenocarcinoma. It can be helpful in cases with metastatic rectal carcinoma, especially those with CK7+/CK20+ or CK20-/CK7- immunophenotype. In this study, CDX2 expression was not influenced by the grade (differentiation) of rectal adenocarcinoma.

Colonic carcinoma metastatic to the endometrium: the importance of clinical history in averting misdiagnosis as a primary endometrial carcinoma

Metastases to endometrium are a rare event. A case of a 53-year-old woman with a previous colon cancer presenting with a dysfunctional uterine bleeding is reported. The curettage specimens consisted of multiple fragments of proliferative endometrial tissue mixed with irregular glands, focally amputated, lined by very cells with elongated, hyperchromatic nuclei and solid sheets of neoplastic cells often filled with necrotic debris and inflammatory cells, resembling endometrioid adenocarcinoma. Neoplastic cells resulted positive at immunohistochemical reaction for CK20, CDX2, p53 and negative for CK7, vimentin, ER, and PR suggesting a metastatic colon adenocarcinoma. Absence of premalignant changes, such as hyperplasia, besides frankly malignant glands in an endometrial curette should be regarded as an alarming feature for a secondary nature mostly from large bowel. In these cases clinical history is crucial and an immunohistochemical panel made up of CK7, CK20, CDX2, p53, vimentin, ER, and PR is useful for the correct diagnosis.

Soy consumption and histopathologic markers in breast tissue using tissue microarrays

This study examined the relation of soy intake with hormonal and proliferation markers in benign and malignant breast tissue using tissue microarrays (TMAs). TMAs with up to 4 malignant and 4 benign tissue samples for 268 breast cancer cases were constructed. Soy intake in early life and in adulthood was assessed by questionnaire. The TMAs were stained for estrogen receptor (ER) alpha, ERbeta, progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2/neu), proliferating cell nuclear antigen (PCNA), and Ki-67 using standard immunohistochemical methods. Logistic regression was applied for statistical analysis. A higher percentage of women showed positive marker expression in malignant than in benign tissue. With one exception, HER2/neu, no significant associations between soy intake and pathologic markers were observed. Early life soy intake was associated with lower HER2/neu and PCNA staining of malignant tissue. In benign tissue, early life soy intake showed higher ER and PR expression, but no difference in proliferation markers. The results of this investigation provide some assurance that soy intake does not adversely affect markers of proliferation. TMAs were shown to be a useful tool for epidemiologic research.

Added value of combined gene and protein expression of CK20 and CEA in non-macroscopically involved lymph nodes of colorectal cancer

A methacarn fixation permits an approach that comprises multiple techniques. In this study the procedure is used to examine 100 mesenteric lymph nodes from patients with colon cancer by means of histology, immunohistochemistry (IHC), and reverse transcriptase polymerase chain reaction (RT-PCR). The evaluated nodes are found to be grossly free of metastases. The combined expression of both messenger RNA (mRNA) and protein is investigated to validate the presence of structural (cytokeratin 20, or CK20) and tumor-specific (carcinoembryonic antigen, or CEA) markers. Histological analysis shows micrometastases on 4 nodes. IHC analysis identifies isolated (CK20 and CEA positive) tumor cells on 14 other nodes. In this group, none of the nodes that are positive for CK20 IHC express the related mRNA. RT-PCR confirms the CEA IHC positivity in 50% of the cases. The double CEA IHC/RT-PCR positivity would have up-staged 33% of the pN0 cases to pN1. This approach offers a technological framework for further studies that aim to validate the clinical significance of protein/mRNA expression of tumor markers in colorectal cancer sentinel lymph nodes.

The human keratins: biology and pathology

The keratins are the typical intermediate filament proteins of epithelia, showing an outstanding degree of molecular diversity. Heteropolymeric filaments are formed by pairing of type I and type II molecules. In humans 54 functional keratin genes exist. They are expressed in highly specific patterns related to the epithelial type and stage of cellular differentiation. About half of all keratins—including numerous keratins characterized only recently—are restricted to the various compartments of hair follicles. As part of the epithelial cytoskeleton, keratins are important for the mechanical stability and integrity of epithelial cells and tissues. Moreover, some keratins also have regulatory functions and are involved in intracellular signaling pathways, e.g. protection from stress, wound healing, and apoptosis. Applying the new consensus nomenclature, this article summarizes, for all human keratins, their cell type and tissue distribution and their functional significance in relation to transgenic mouse models and human hereditary keratin diseases. Furthermore, since keratins also exhibit characteristic expression patterns in human tumors, several of them (notably K5, K7, K8/K18, K19, and K20) have great importance in immunohistochemical tumor diagnosis of carcinomas, in particular of unclear metastases and in precise classification and subtyping. Future research might open further fields of clinical application for this remarkable protein family.