Subcellular Localization of Immunohistochemical Signals

[Clinical, histological and genetic correlations in melanocytic tumours with chromosomal rearrangements]

In some tumoral subtypes chromosomal translocations lead to an oncogenic chimeric protein acting as a tumorigenesis driver event. The main fusion model combines the promoter swapping of an inactivated tumor suppressor gene and a functional kinase that evades its regulatory system. The range of described fusions keeps growing in the 2023 WHO classification of melanocytic tumours. It is not limited to the group of Spitz tumours as previously but now extends to blue tumours and dermal tumours with a melanocytic phenotype. Molecular pathology helps detect these anomalies using clinical and morphological features. This analysis is essential as this strongly conditions the adapted local treatment of such tumours who are often overtreated.

Super-resolution imaging of flat-mounted whole mouse cornea

Super-resolution microscopy revolutionized biomedical research with significantly improved imaging resolution down to the molecular scale. To date, only limited studies reported multi-color super-resolution imaging of thin tissue slices mainly because of unavailable staining protocols and incompatible imaging techniques. Here, we show the first super-resolution imaging of flat-mounted whole mouse cornea using single-molecule localization microscopy (SMLM). We optimized immunofluorescence staining protocols for β-Tubulin, Vimentin, Peroxisome marker (PMP70), and Histone-H4 in whole mouse corneas. Using the optimized staining protocols, we imaged these four intracellular protein structures in the epithelium and endothelium layers of flat-mounted mouse corneas. We also achieved simultaneous two-color spectroscopic SMLM (sSMLM) imaging of β-Tubulin and Histone-H4 in corneal endothelial cells. The spatial localization precision of sSMLM in these studies was around 20-nm. This work sets the stage for investigating multiple intracellular alterations in corneal diseases at a nanoscopic resolution using whole corneal flat-mount beyond cell cultures.

Precise Immunodetection of PTEN Protein in Human Neoplasia

PTEN is a major tumor-suppressor protein whose expression and biological activity are frequently diminished in sporadic or inherited cancers. PTEN gene deletion or loss-of-function mutations favor tumor cell growth and are commonly found in clinical practice. In addition, diminished PTEN protein expression is also frequently observed in tumor samples from cancer patients in the absence of PTEN gene alterations. This makes PTEN protein levels a potential biomarker parameter in clinical oncology, which can guide therapeutic decisions. The specific detection of PTEN protein can be achieved by using highly defined anti-PTEN monoclonal antibodies (mAbs), characterized with precision in terms of sensitivity for the detection technique, specificity for PTEN binding, and constraints of epitope recognition. This is especially relevant taking into consideration that PTEN is highly targeted by mutations and posttranslational modifications, and different PTEN protein isoforms exist. The precise characterization of anti-PTEN mAb reactivity is an important step in the validation of these reagents as diagnostic and prognostic tools in clinical oncology, including their routine use in analytical immunohistochemistry (IHC). Here, we review the current status on the use of well-defined anti-PTEN mAbs for PTEN immunodetection in the clinical context and discuss their potential usefulness and limitations for a more precise cancer diagnosis and patient benefit.

Diagnostic Utility of Thyroid Transcription Factor-1 in Ovarian Carcinoma and Its Relationship With Clinicopathologic Prognostic Parameters

Although thyroid transcription factor-1 (TTF-1) is considered a relatively sensitive and specific marker for lung and thyroid neoplasms, it can occasionally be expressed in other tumors. Few immunohistochemical studies have been conducted on TTF-1 expression in ovarian carcinomas with discrepant results. To date, only 1 study compared different TTF-1 clones in ovarian carcinoma. This study is designed to evaluate the expression of TTF-1 clones in ovarian carcinomas and investigate TTF-1 association with clinicopathologic prognostic parameters. A retrospective immunohistochemical study was conducted on 62 primary ovarian carcinomas and 15 normal ovarian tissues using 2 clones of TTF-1 antibody (SPT24 and 8G7G3/1). Nuclear expression of SPT24 and 8G7G3/1 clones of TTF-1 was detected in 17.7% and 3.2% of ovarian carcinomas, respectively. Positive cytoplasmic immunostaining of clone SPT24 was detected in 1.6% of cases. In contrast, normal ovarian tissue showed negative expression of both clones. A highly significant difference was observed between both clones regarding their sensitivity in ovarian carcinomas (P=0.004). A significant inverse relationship was observed between TTF-1 (SPT24 clone) expression and tumor stage (P=0.022). TTF-1 expression is not exclusive to lung and thyroid tissue. It is expressed in ovarian carcinomas where clone SPT24 is more sensitive than clone 8G7G3/1. TTF-1 might be of diagnostic utility in evaluating neoplasms of unknown primary origin as well as adenocarcinomas involving the lung in patients with a history of a gynecologic malignancy. Moreover, TTF-1 expression might be a good prognostic factor in ovarian carcinoma.

Aberrant expression of glycogen synthase kinase-3β in human breast and head and neck cancer

Glycogen Synthase Kinase-3β (GSK-3β), a serine/threonine protein kinase, has been implicated as a potential therapeutic target in human cancer. The objective of the present study was to evaluate aberrant expression of GSK-3β as a potential biomarker in human breast and head and neck cancers. Nuclear/cytosolic fractionation, immunoblotting and immunohistochemical staining was used to study the expression of GSK-3β in human breast and head and neck cancer. Aberrant nuclear accumulation of GSK-3β in five human breast cancer cell lines was demonstrated and in 89/128 (70%) human breast carcinomas, whereas no detectable expression of GSK-3β was found in benign breast tissue. Nuclear GSK-3β expression was associated with HER-2 positive tumors (P=0.02) and non-triple negative breast carcinomas (P=0.0001), although nuclear GSK-3β was observed in some samples across all breast cancer subtypes. Aberrant nuclear expression of GSK-3β was found in 11/15 (73%) squamous cell head and neck carcinomas, whereas weak or no detectable expression of GSK-3β was found in benign salivary gland and other benign head and neck tissues. These results support the hypothesis that aberrant nuclear GSK-3β may represent a potential target for the clinical treatment of human breast and squamous cell carcinoma.

Reversed polarity of the glandular epithelial cells in micropapillary carcinoma of the large intestine and the EMA/MUC1 immunostain

Micropapillary carcinoma of the colon and rectum is associated with an adverse prognosis. This tumour type displays reverse polarity of the tumour cells and is stated to be characterised by an inside-out epithelial membrane antigen (EMA)/MUC1 staining. Nine cases of primary colorectal carcinoma and one omental metastasis were studied by means of immunohistochemistry, using antibodies to detect EMA, MUC1, MUC2, MUC3, MUC5AC, MUC6, CD10, CA125, carcinoembryonic antigen (CEA). The inside-out pattern staining with EMA/MUC1 ranged from diffuse circumferential through focal and partial to negative, but in some cases CEA, MUC3 and CD10 also showed this pattern staining, sometimes more clearly than did EMA or MUC1. The reverse polarity of colorectal micropapillary carcinomas is sometimes better visualised by immunostains other than EMA/MUC1.

Quality Management of the Immunohistochemistry Laboratory: A Practical Guide

Governmental regulations and most published guidelines do not provide specific guidance on implementation of quality management (QM) programs for immunohistochemistry (IHC) assays in Anatomic Pathology. QM of IHC consists of 3 main components: quality control, quality assurance, and quality improvement initiatives, each entailing distinctive but interrelated objectives. Discussion of the principles and some specific practices involved in these phases of QM of the IHC laboratory are therefore offered in this review, with an admitted emphasis on pragmatism.

Molecular mechanisms underlying antiproliferative and differentiating responses of hepatocarcinoma cells to subthermal electric stimulation

Capacitive Resistive Electric Transfer (CRET) therapy applies currents of 0.4–0.6 MHz to treatment of inflammatory and musculoskeletal injuries. Previous studies have shown that intermittent exposure to CRET currents at subthermal doses exert cytotoxic or antiproliferative effects in human neuroblastoma or hepatocarcinoma cells, respectively. It has been proposed that such effects would be mediated by cell cycle arrest and by changes in the expression of cyclins and cyclin-dependent kinase inhibitors. The present work focuses on the study of the molecular mechanisms involved in CRET-induced cytostasis and investigates the possibility that the cellular response to the treatment extends to other phenomena, including induction of apoptosis and/or of changes in the differentiation stage of hepatocarcinoma cells. The obtained results show that the reported antiproliferative action of intermittent stimulation (5 m On/4 h Off) with 0.57 MHz, sine wave signal at a current density of 50 µA/mm², could be mediated by significant increase of the apoptotic rate as well as significant changes in the expression of proteins p53 and Bcl-2. The results also revealed a significantly decreased expression of alpha-fetoprotein in the treated samples, which, together with an increased concentration of albumin released into the medium by the stimulated cells, can be interpreted as evidence of a transient cytodifferentiating response elicited by the current. The fact that this type of electrical stimulation is capable of promoting both, differentiation and cell cycle arrest in human cancer cells, is of potential interest for a possible extension of the applications of CRET therapy towards the field of oncology.

Patterns of FOXE1 expression in papillary thyroid carcinoma by immunohistochemistry

BACKGROUND

FOXE1, a thyroid-specific transcription factor also known as TTF-2, was recently identified as a major genetic risk factor for papillary thyroid carcinoma (PTC). Its role in thyroid carcinogenesis, however, remains unknown. The purpose of the present study was to assess the relationship between the FOXE1 immunohistochemical features and the clinical and genetic characteristics of PTC.

METHODS

Immunohistochemical staining of FOXE1 was performed in 48 PTC cases. Two single nucleotide polymorphisms immediately inside (rs1867277) or in the vicinity (rs965513) of the FOXE1 gene were genotyped by direct sequencing. Histopathological, clinical, and genetic data were included in statistical analyses.

RESULTS

FOXE1 exhibited cytoplasmic overexpression in tumor tissue compared to the normal counterpart (p<0.001). Both cancer and normal thyroid cells demonstrated the highest FOXE1 scores in the areas closest to the tumor border (<300 μm) compared with more distant areas (p<0.001). No differences in FOXE1 staining distributions were found between microcarcinomas and PTC of larger size, between different histopathological variants of PTC, and encapsulated and nonencapsulated tumors. Multivariate regression analysis revealed that nuclear FOXE1 expression in neoplastic cells in the vicinity of the tumor border independently associated with the genotype at rs1867277 (the dominant model of inheritance, p=0.037) and tumor multifocality (p=0.032), and with marginal significance with capsular invasion (p=0.051).

CONCLUSIONS

FOXE1 overexpression and translocation to the cytoplasm are phenotypic hallmarks of tumor cells suggesting that FOXE1 is involved in the pathogenesis of PTC. Nuclear FOXE1 expression in tumor cells in the vicinity of the PTC border is associated with the presence of a risk allele of rs1867277 (c.-238G>A) in the 5' untranslated region of the FOXE1 gene, as well as with pathological characteristics of PTC, suggesting possible FOXE1 involvement in the facilitation of tumor development beginning at an early stage.

The scanning ion conductance microscope for cellular physiology

The quest for nonoptical imaging methods that can surmount light diffraction limits resulted in the development of scanning probe microscopes. However, most of the existing methods are not quite suitable for studying biological samples. The scanning ion conductance microscope (SICM) bridges the gap between the resolution capabilities of atomic force microscope and scanning electron microscope and functional capabilities of conventional light microscope. A nanopipette mounted on a three-axis piezo-actuator, scans a sample of interest and ion current is measured between the pipette tip and the sample. The feedback control system always keeps a certain distance between the sample and the pipette so the pipette never touches the sample. At the same time pipette movement is recorded and this generates a three-dimensional topographical image of the sample surface. SICM represents an alternative to conventional high-resolution microscopy, especially in imaging topography of live biological samples. In addition, the nanopipette probe provides a host of added modalities, for example using the same pipette and feedback control for efficient approach and seal with the cell membrane for ion channel recording. SICM can be combined in one instrument with optical and fluorescent methods and allows drawing structure-function correlations. It can also be used for precise mechanical force measurements as well as vehicle to apply pressure with precision. This can be done on living cells and tissues for prolonged periods of time without them loosing viability. The SICM is a multifunctional instrument, and it is maturing rapidly and will open even more possibilities in the near future.

Microvillous inclusion disease: a clinicopathologic study of 17 cases from the UK

BACKGROUND

Microvillous inclusion disease (MVID) is a rare congenital disease producing intractable secretory diarrhea in early infancy. It is characterized by diffuse intestinal villous atrophy with no inflammatory reaction. Ultrastructural identification of apical microvillous inclusions in the surface enterocytes is diagnostic. However, there is difficulty in the diagnosis of MVID due to the existence of variants (e.g., microvillous dystrophy), possible disease resolution, and tissue orientation for electron microscopy (EM). The authors analyzed materials from 4 patients with MVID from a single institution. The morphologic features, distribution of lesions, biomarkers, and complementary ultrastructural characteristics were studied.

DESIGN

Materials of MVID cases were collected from 6 different hospitals in the United Kingdom between 1990 and 2008. Epidemiological data, including age range, median, mode, sex ratios, and follow-up, were retrieved. All intestinal biopsy specimens were analyzed histologically, histochemically (for PAS, n = 17), immunohistochemically (for CD10, n = 2 and polyclonal CEA, n = 4), and ultrastructurally (n = 9).

RESULTS

Ultrastructurally, apical microvillous inclusions in surface enterocytes in duodenal biopsies were identified in all cases, while 1 case had variant morphology (microvillous dystrophy and very occasionally atypical microvillous inclusions). Tissue orientation for EM was supportive for identification of inclusions in apical enterocytes. Morphologically, a bubbly vacuolated appearance of the apical cytoplasm with extensive or patchy absence of the brush border with occasional cytoplasm inclusions was observed in the enterocytes. Some of these changes vaguely resembled gastric mucin cell metaplasia. Architecturally, villous blunting with either crypt hypoplasia or hyperplasia and absence of inflammation were common findings. The epithelial changes were also found in colon biopsies. PAS, CD10, and p-CEA showed a bright apical cytoplasmic blush/staining, which correlated ultrastructurally with apical granules with inclusions of variable electron density in all cases. These stains also highlighted the targetoid inclusions.

CONCLUSION

Besides electron microscopy identification of inclusions, the light microscopic morphological features together with the biomarker studies highlighting the apical cytoplasmic blush are quite unique and diagnostic of MVID. Furthermore, it is the opinion of the authors that a diagnosis of MVID can be made without electron microscopy.

A reevaluation of the clinical significance of histological subtyping of non--small-cell lung carcinoma: diagnostic algorithms in the era of personalized treatments

The classification of lung cancer has always been primarily based on the morphologic assessment of routinely stained histological sections, but this approach may be difficult or even unfeasible in cytological preparations or small biopsies. Moreover, the simplistic dichotomization between small-cell carcinoma and non-small cell carcinoma (NSCLC) should be overcome, as new drugs have been discovered that are effective in specific subtypes of lung cancer. A more accurate characterization of NSCLC, however, may be hard in carcinomas lacking clear-cut signs of differentiation. The incorporation into the diagnostic algorithm of poorly differentiated carcinomas of an immunohistochemical panel including markers of squamous (high-molecular-weight cytokeratins, p63) and glandular (TTF-1, cytokeratin 7) cell differentiation seems the most promising approach. The evaluation of lung cancer for gene mutations, gene amplification, tumor-related angiogenesis, expression levels of DNA repair genes and genomic or proteomic profiles represents an exciting challenge for the pathologist in the near future.

MAD2 as a key component of mitotic checkpoint: A probable prognostic factor for gastric cancer

We studied the subcellular localization of MAD2 in normal human tissues and gastric cancers. MAD2 showed nuclear and cytoplasmic localization in normal tissues such as muscle, testis, thyroid gland, cerebrum, trachea, and skin; blood vessels in some organs were also MAD2+. In normal stomach, MAD2 was expressed mainly in cytoplasm but showed nuclear staining in the majority of gastric cancers. MAD2 was significantly overexpressed in gastric cancer compared with matched adjacent tissues (P < .001), and expression was related to differentiation and other clinical parameters of cancer (P < .001). The cancer/adjacent normal tissue (C/N) ratio of MAD2 expression was higher than 2 and more frequently observed in patients with lymph gland metastasis (P < .05) and related to cancer differentiation. Our findings suggest that the steady-state amount of MAD2 inside cells may serve as a molecular switch in mitotic checkpoint control and that the subcellular localizations of this spindle protein undergo a shift during malignant transformation. The change of MAD2 expression may be involved mainly in gastric carcinogenesis and associated with the prognosis of gastric cancer; a C/N of more than 2 may be associated with the worse prognosis for survival in gastric carcinoma.

Pathologic evaluation of unknown primary cancer

The pathologic approach to metastases of unknown primary cancer (UPC) is stepwise and uses the clinical context, morphology, and, where necessary, immunohistochemistry (IHC). This review covers the initial approach to a UPC biopsy; the diagnosis of malignancy and broad tumor typing into carcinoma, melanoma, lymphoma, or sarcoma; and further subtyping of carcinoma into germ cell (broadly included), squamous, neuroendocrine, and solid organ including liver and renal, and adenocarcinomas. Finally, for adenocarcinoma, the prediction of primary tumor site, including lung, pancreas, stomach, colon, ovary, prostate, and breast, is discussed. For each tumor type, the morphologic features are presented alongside established useful IHC markers, with a description of their staining patterns and common diagnostic dilemmas. Optimal tissue handling and IHC interpretation, quality assurance, and limitations also are discussed. The target readership is oncologists, but other clinicians and trainee pathologists also may find the content of use.

Quantitative evaluation of myenteric ganglion cells in normal human left colon: implications for histopathological analysis

The analysis of myenteric neurons is becoming increasingly important for the assessment of enteric nervous system injury and degeneration occurring in motor disorders of the gut. Limited information is presently available on the quantitative estimation of myenteric neurons and glial cells in paraffin-embedded colonic sections; additional data would be useful for diagnostic purposes. In this morphometric study, we performed immunohistochemistry to count myenteric neurons and glial cells in paraffin sections of human colon. Serial cross sections of formalin-fixed paraffin-embedded full-thickness normal human left colon (n = 10, age-range: 50-72 years) were examined. HuC/D and S100beta antigens were found to be the best markers for the detection of neurons and glial cells, respectively. Significant correlations were noted between the numbers of neurons/glial cells and the respective myenteric ganglion areas. These findings suggest that HuC/D-S100beta-immunostained paraffin cross sections of human colon can be regarded as valuable tools for the quantitative estimation of myenteric neurons and glial cells. Based on the present method, only a limited number of paraffin sections are needed for reliable quantitative assessments of myenteric ganglion cells, thus allowing fast and simple approaches in the settings of the histopathological diagnosis of colonic motility disorders and retrospective evaluations of pathological archival tissue specimens.

Proteomic analysis of RCL2 paraffin-embedded tissues

Histopathological diagnosis in most of the world's hospitals is based upon formalin-fixed and paraffin-embedded (FFPE) tissues. Although this standard fixation and embedding procedure keeps the tissue in excellent form for morphological and immunohistological analysis, FFPE is inappropriate for nucleic acids and protein studies. We investigated the potential value of RCL2, a new non-toxic fixative, for sparing proteins preserved in paraffin-embedded tissues. Normal colonic mucosa tissue was fixed in RCL2 prior to paraffin embedding (RCL2P), and then processed for quality and quantity of protein conservation, as compared to frozen and FFPE tissues using complementary proteomic analysis approaches. Using 4 different protein extraction protocols, RCL2P tissue consistently showed the highest protein yield. Similar protein patterns were observed with RCL2P and frozen tissues using mono and bi-dimensional electrophoresis. Moreover, membrane, cytoplasmic and nuclear proteins, as well as phosphorylated proteins, were successfully detected using western-blot. Furthermore, protein patterns observed by mass spectrometry analysis after laser-captured microdissection were found to be identical for frozen and RCL2-fixed tissues. At last, immunohistochemistry using various antibodies showed comparable results between both tissue storage methods. We concluded that RCL2 has great potential for performing both morphological and molecular analyses on the same archival paraffin-embedded tissue sample, and can be a new method for investigating protein biomarkers.

Combined assessment of EGFR pathway-related molecular markers and prognosis of NSCLC patients

The purpose of this study is to evaluate the prognostic value of the combined assessment of multiple molecular markers related to the epidermal growth factor receptor (EGFR) pathway in resected non-small cell lung cancer (NSCLC) patients. Tumour specimens of 178 NSCLC patients were collected and analysed for EGFR and KRAS mutation status by DNA sequencing, and for EGFR copy number by fluorescent in situ hybridisation. Tissue microarrays were generated and used to determine the expression of multiple EGFR pathway-related proteins by immunohistochemistry. We analysed the association between each marker and patient prognosis. Univariate analyses for each clinical variable and each molecular marker were performed using Kaplan–Meier curves and log-rank tests. From these results, we selected the variables KRAS mutations and expression of cytoplasmic EGFR, granular pERK, nuclear pSTAT3, cytoplasmic E-cadherin and cytoplasmic pCMET to enter into a Cox proportional hazards model, along with stage as the strongest clinical variable related with prognosis. Of the EGFR-related markers evaluated here, the markers EGFR, pERK, pSTAT3, E-cadherin, pCMET and mutations in KRAS were associated with survival when analysed in combination in our patient cohort, with P=0.00015 as the P-value for a test of the additional impact of markers on prognosis, after taking stage into consideration. Confirmation of the impact of these markers in independent studies will be necessary.

Refinement of breast cancer classification by molecular characterization of histological special types

Most invasive breast cancers are classified as invasive ductal carcinoma not otherwise specified (IDC NOS), whereas about 25% are defined as histological 'special types'. These special-type breast cancers are categorized into at least 17 discrete pathological entities; however, whether these also constitute discrete molecular entities remains to be determined. Current therapy decision-making is increasingly governed by the molecular classification of breast cancer (luminal, basal-like, HER2+). The molecular classification is derived from mainly IDC NOS and it is unknown whether this classification applies to all histological subtypes. We aimed to refine the breast cancer classification systems by analysing a series of 11 histological special types [invasive lobular carcinoma (ILC), tubular, mucinous A, mucinous B, neuroendocrine, apocrine, IDC with osteoclastic giant cells, micropapillary, adenoid cystic, metaplastic, and medullary carcinoma] using immunohistochemistry and genome-wide gene expression profiling. Hierarchical clustering analysis confirmed that some histological special types constitute discrete entities, such as micropapillary carcinoma, but also revealed that others, including tubular and lobular carcinoma, are very similar at the transcriptome level. When classified by expression profiling, IDC NOS and ILC contain all molecular breast cancer types (ie luminal, basal-like, HER2+), whereas histological special-type cancers, apart from apocrine carcinoma, are homogeneous and only belong to one molecular subtype. Our analysis also revealed that some special types associated with a good prognosis, such as medullary and adenoid cystic carcinomas, display a poor prognosis basal-like transcriptome, providing strong circumstantial evidence that basal-like cancers constitute a heterogeneous group. Taken together, our results imply that the correct classification of breast cancers of special histological type will allow a more accurate prognostication of breast cancer patients and facilitate the identification of optimal therapeutic strategies.

Quantification of diverse subcellular immunohistochemical markers with clinicobiological relevancies: validation of a new computer-assisted image analysis procedure

Tissue microarray technology and immunohistochemical techniques have become a routine and indispensable tool for current anatomical pathology diagnosis. However, manual quantification by eye is relatively slow and subjective, and the use of digital image analysis software to extract information of immunostained specimens is an area of ongoing research, especially when the immunohistochemical signals have different localization in the cells (nuclear, membrane, cytoplasm). To minimize critical aspects of manual quantitative data acquisition, we generated semi-automated image-processing steps for the quantification of individual stained cells with immunohistochemical staining of different subcellular location. The precision of these macros was evaluated in 196 digital colour images of different Hodgkin lymphoma biopsies stained for different nuclear (Ki67, p53), cytoplasmic (TIA-1, CD68) and membrane markers (CD4, CD8, CD56, HLA-Dr). Semi-automated counts were compared to those obtained manually by three separate observers. Paired t-tests demonstrated significant differences between intra- and inter-observer measurements, with more substantial variability when the cellular density of the digital images was > 100 positive cells/image. Overall, variability was more pronounced for intra-observer than for inter-observer comparisons, especially for cytoplasmic and membrane staining patterns (P < 0.0001 and P = 0.050). The comparison between the semi-automated and manual microscopic measurement methods indicates significantly lower variability in the results yielded by the former method. Our semi-automated computerized method eliminates the major causes of observer variability and may be considered a valid alternative to manual microscopic quantification for diagnostic, prognostic and therapeutic purposes.

Intestinal clear cell sarcoma with melanocytic differentiation and EWS [corrected] rearrangement: report of a case

A clear cell sarcoma-like tumor with osteoclast-like giant cells of the gastrointestinal tract without immunoexpression of CD117 was recently proposed as a new tumor entity. In this article, a case of a 37-year-old man with a neoplasm of the jejunum composed of polygonal cells with clear to eosinophilic cytoplasm forming nests and fascicles is reported. Giant cells were not identified. Immunohistochemically, the tumor cells expressed strongly S100 protein, human melanoma black 45, platelet-derived growth factor receptor alpha, B-cell lymphoma 2, p53, and to a lesser extent vimentin, neuron-specific enolase, and epithelial membrane antigen. Mindbomb homolog-1 index was 35%. Immunoreactivity for CD34 and CD117 was negative. The fluorescence in situ hybridization analysis showed a translocation involving chromosome 22q12, the diagnostic hallmark of clear cell sarcoma of soft tissues. This case indicates a close histogenetic relationship with the recently reported clear cell sarcoma with osteoclast-like giant cells of the gastrointestinal tract, as well as with the clear cell sarcoma of soft tissues.

Technical pitfalls potentially affecting diagnoses in immunohistochemistry

Result of the immunohistochemical reactions routinely used in diagnostic surgical pathology should be properly interpreted, since false results, related to technical and interpretative pitfalls may lead to incorrect diagnosis. The main sources of such pitfalls are reviewed, analytically described and related to different steps (fixation, tissue processing and embedding, decalcification, antigen retrieval) which may affect the accuracy of immunohistochemistry. In addition, the presence of endogenous enzyme activity, improper binding of avidin to endogenous biotin, incorrect use of antibodies, chromogen and detection systems, as well as incorrect interpretation may produce unreliable data. The high frequency and extension of such pitfalls make mandatory the use of internal and external controls and adoption of cross-validation programmes. The present study, supported by an extensive review of the related literature, is intended as a guideline leading to proper interpretation of immunohistochemical data, an essential component of the diagnostic process. Experience on the antigen retrieval procedures for different antigens is also presented.

Wilms' tumour 1 gene expression is increased in hepatocellular carcinoma and associated with poor prognosis

BACKGROUND/AIMS

Wilms' tumour 1 gene (WT1) was originally isolated as a tumour-suppressor gene. We investigated the expression of WT1 in hepatocellular carcinoma (HCC; T) and in non-cancerous hepatic tissues (non-tumour: NT) from patients with chronic liver diseases, and then examined the role of WT1 in the carcinogenesis or prognosis of HCC.

METHODS

The expression of WT1 in T and NT from 50 patients with HCC was investigated using Western blotting, immunohistochemistry and real-time reverse transcriptase-polymerase chain reaction (RT-PCR). We also examined whether WT1 expression was related to clinicopathological factors in individual patients in addition to prognostic factors in 50 patients with HCC and in 26 without HCC.

RESULTS

Western blotting and immunohistochemical staining showed that WT1 was overexpressed in T compared with NT (P<0.001) and real-time reverse transcriptase-polymerase chain reaction (RT-PCR) showed that WT1 mRNA expression was similarly increased. Overexpressed WT1 in HCC was significantly associated with T factors at the TNM stage, and short doubling time of HCC. Univariate and multivariate analyses revealed that WT1 overexpression was an independent prognostic factor for HCC. The disease-free survival period in patients with overexpressed WT1 in NT tissues was significantly reduced.

CONCLUSION

The expression of WT1 is increased more in HCC than in non-tumour tissues. Moreover, overexpressed WT1 was associated with tumour growth, and resulted in a worsening prognosis of HCC. Our findings from NT tissues revealed that WT1 overexpression might contribute to oncogenic potential.

Metastases to the breast from nonbreast solid neoplasms: presentation and determinants of survival

BACKGROUND

Metastasis to the breast is rare, but it must be considered in the differential diagnosis of a breast mass. The purpose of this study was to identify clinical characteristics and outcomes associated with this entity to identify determinants of survival.

METHODS

Between 1983 and 1998, 169 patients were confirmed by pathology to have metastasis to the breast from nonbreast solid organ primary tumors at University of Texas M. D. Anderson Cancer Center. Medical records were retrospectively reviewed for clinicopathological characteristics. Survival was determined by Kaplan-Meier analysis.

RESULTS

The median age was 51 years (range, 13-85). One hundred forty-nine (88.2%) patients had a prior history of cancer. Ninety-one (53.9%) patients presented with additional systemic metastases. The most common histology identified was melanoma (65 patients, 38.5%). In most patients (77%), the diagnosis was initially made through physical examination. The median survival from the time the breast metastasis was diagnosed was 10 months (range, 0.4-192.7). On univariate analysis, a significantly better survival was observed in patients who had no evidence of other disease at the time of diagnosis (P = .0036), patients with neuroendocrine tumors (P = .023), and patients who underwent surgical resection for breast metastases (P = .0001). On multivariate analysis, patients who did not have surgery were 88% more likely to die than those who did (P < 0.001).

CONCLUSIONS

Expected survival with metastasis to the breast is poor, therefore, local therapy should be tailored to each individual. The association between overall survival and surgical resection of metastases to the breast should be further investigated.

Ligneous conjunctivitis: a clinicopathological, immunohistochemical, and genetic study including the treatment of two sisters with multiorgan involvement

Ligneous conjunctivitis (LC) is a rare disease characterized by wood-like pseudomembranes developing on the ocular and extraocular mucosae secondary to plasminogen (PLG) deficiency. In this paper, we report two cases of LC in two sisters of 57 and 62 years of age that presented with recurrent, bilateral pseudomembranes on conjunctiva and a history of consanguinity and deafness. Pseudomembranes showed superficial and/or subepithelial deposits of eosinophilic amorphous hyaline, amyloid-like material with a variable proportion of granulation tissue, and inflammatory cells. The eosinophilic deposits were negative for Congo red stain, immunoreactive for fibrinogen, and consistently negative for amyloid A component, transthyretin, beta(2)-microglobulin, albumin, fibronectin, collagen type IV, vimentin, and cytokeratins. Among inflammatory cells, a percentage of positivity of roughly 60% for lymphocytes T (CD3+) and 40% for lymphocytes B (CD8+), with a relation of cytotoxic/helper (CD8/4) T cells of 3:2, was found. In one case, nasal polyps and recurrent gastric peptic ulcer were also characterized by the same subepithelial hyaline deposits. A novel homozygous point mutation c.1856 C>T was found in exon 15 of the PLG gene in both patients. Amniotic membrane transplantation was done in one case with promising results.

CCND1 amplification and cyclin D1 expression in breast cancer and their relation with proteomic subgroups and patient outcome

INTRODUCTION

Despite strong evidence regarding the role of CCND1 amplification and protein overexpression in breast carcinoma, the associations between CCND1 amplification/cyclin D1 overexpression and clinicopathological variables and clinical outcome remain controversial.

AIMS OF THE STUDY

(1) to correlate cyclin D1 expression with gene amplification; (2) to analyse the correlations between CCND1 amplification and overexpression with clinicopathological features and patients' outcome in invasive breast cancer; (3) to define the prevalence and clinical significance of cyclin D1 overexpression and CCND1 amplification in ER positive breast carcinomas (4) to define the prevalence of cyclin D1 overexpression and CCND1 amplification in breast cancers with basal-like immunophenotype.

MATERIALS AND METHODS

CCND1 amplification and protein expression were assessed on a tissue microarray containing 880 unselected invasive breast cancer cases, by means of chromogenic in situ hybridisation using the Spotlight CCND1 amplification probe and immunohistochemistry, using the rabbit monoclonal antibody SP4.

RESULTS

A total of 59/613 tumours (9.6%) showed CCND1 amplification and 224/514 (43.6%) showed strong cyclin D1 expression. A strong positive correlation between CCND1 amplification and higher levels of cyclin D1 expression was found (P < 0.001). Basal-like cancers showed infrequent CCND1 amplification and cyclin D1 overexpression (P < 0.001). Both CCND1 amplification and cyclin D1 expression were associated with positive ER status. CCND1 gene amplification was an independent prognostic factor for patients with ER positive breast cancer.

CONCLUSION

Our results demonstrate a strong correlation between CCND1 amplification and its protein expression in breast cancer. However, protein expression is more pervasive than gene amplification and associated with ER expression.

Subcellular localization of the spindle proteins Aurora A, Mad2, and BUBR1 assessed by immunohistochemistry

The spindle checkpoint, the primary mechanism to ensure that two daughter cells receive the same amount of DNA, is compromised in many malignant tumors and has been implicated as a contributor to aneuploidy and carcinogenesis. The extent of expression and subcellular localization of the spindle proteins Aurora A, Mad2, and BUBR1 varies considerably in different immunohistochemical (IHC) reports from archival tumor tissues. Given the conflicting reports in the literature about the localization of these proteins, we examined the subcellular localization of Aurora kinase A, Mad2, and BUBR1 in normal and cancerous human tissues by IHC. In normal tissues, Aurora A was mainly localized to the nucleus when monoclonal or purified polyclonal antibodies were used, and Mad2 was localized to the nucleus, whereas BUBR1 was localized to the cytoplasm. In malignant tissues, Aurora A showed additional staining in the cytoplasm in the majority of tumors analyzed. Furthermore, BUBR1 was also localized to both the nucleus and cytoplasm in a significant fraction of tumors. Subcellular localization of Mad2 was similar in normal and malignant tissues. Thus, the validity of some earlier IHC studies of Aurora A, Mad2, and BUBR1 should be reconsidered, indicating that high-quality antibodies and a high-alkaline antigen-retrieval technique are required to achieve optimal results. We conclude that the subcellular localizations of these spindle proteins are different, although they have overlapping biological functions, and that Aurora A and BUBR1 undergo a shift in the subcellular localization during malignant transformation.

Asymmetric localization of Notch2 on the microvillous surface in choroid plexus epithelial cells

Notch family molecules are transmembrane receptors that play various roles in contact-dependent cell-cell interactions in a wide range of organs. In the brain, Notch2, but not the other members of Notch, is expressed in the choroid plexus at an exceptionally high level. We immunohistochemically examined the cellular and subcellular localization of Notch2 protein in the choroid plexus using confocal and electron microscopy. Unexpectedly, Notch2 was asymmetrically localized on the microvillous surface of epithelial cells in the choroid plexus of both postnatal and adult rats. This localization pattern of Notch2 suggests its novel and unknown role independent of contact with adjacent cells in the choroid plexus. In organotypic cultures of the choroid plexus, the addition of anti-Notch2 antibody resulted in deformation of microvilli in epithelial cells, which suggests a role of Notch2 in the maintenance of the microvillous structure in choroid plexus epithelial cells.

A novel fixative improves opportunities of nucleic acids and proteomic analysis in human archive's tissues

All tissues from biopsy or surgery origin are fixed and paraffin embedded as a routine procedure in the hospital departments of pathology. The traditional method of tissue preservation is the fixation in formalin, followed by paraffin embedding. In this way tissue's integrity is ensured also for future analyses, because there is no further chemical degradation of nucleic acids and proteins in tissues embedded in paraffin. After few sections for the histopathological examination the tissues are stored for decades in the hospital archives. Even if formalin fixation compromises the quality and integrity of nucleic acids, it has already been demonstrated that it is possible to recover and analyze DNA and RNA from these archive's tissues, even of autopsy origin. Protein analysis is on the contrary completely blocked, due to the fact that formalin fixation creates covalent links between proteins and the only way to study protein expression is immunohistochemistry. In this study we present our results concerning the use of a new formalin free fixative, the FineFIX. After extraction of nucleic acids, PCR and RT-PCR analyses were performed in DNA and RNA respectively. For DNA analysis it was possible to obtain amplicons of 2400 bps, while in formalin-fixed samples the maximum length achieved was less than 400 bps. RT-PCR analysis show that it was possible to study RNA fragments of 600 bps from FineFIX fixed tissues, against a maximum length of about 150 bps achieved by formalin-fixed tissues. These tissues were analyzed also by Western Blot analysis, showing that the proteins obtained from FineFIX treated samples are amenable and comparable in quality with those obtained from fresh frozen tissues. Protein extracts from FineFix treated tissues were also compared with fresh tissues'ones by two dimensional electrophoresis, demonstrating that the protein pattern were well comparable for number and distribution of the spots.

Breast tumor resembling the tall cell variant of papillary thyroid carcinoma: a case report

The breast tumor resembling the tall cell variant of papillary thyroid carcinoma is a very unusual mammary carcinoma whose histologic and predominant nuclear features mimic a papillary thyroid carcinoma. We report the case of a 64-year-old woman who presented with a palpable nodule in the right breast. Fine needle aspiration disclosed abundant cellularity with isolated cells, sheets, and papillary formations of epithelial cells with nuclear grooves. Histologically, the neoplastic cells were arranged in a solid to papillary architecture, with follicular-like and cribriform areas. The cells were columnar to cuboidal with eosinophilic cytoplasm, clear chromatin, nuclear grooves, and occasional nuclear pseudoinclusions. Tumor cells were positive for cytokeratins, alpha and beta-estrogen receptors, progesterone receptor, androgen receptor, CEA, and bcl-2. We searched for BRAF mutations with negative results. Recognizing the cytologic and histologic characteristics of these peculiar mammary tumors that mimic thyroid carcinomas can avoid unnecessary clinical investigations.

Combined High-Grade Basal Cell Carcinoma and Malignant Melanoma of the Skin (???Malignant Basomelanocytic Tumor???)

We describe two cases of a malignant cutaneous neoplasm with combined phenotypical features of high-grade basal cell carcinoma and malignant melanoma. Some tumor cells showed a keratinocytic phenotype (cytokeratins, p63) and others a melanocytic phenotype (HMB-45, MART-1, Melan-A, S100-protein). We favor the hypothesis of a tumor with bidirectional keratinocytic and melanocytic differentiation, an exceptionally rare event.

Cyclooxygenase-2 in normal, hyperplastic and neoplastic follicular cells of the human thyroid gland

This study was undertaken to investigate cyclooxygenase-2 (COX-2) expression in follicular cells of the human thyroid. COX-2 expression was studied immunohistochemically in a total of 174 samples. COX-2 immunoreactivity was confined to the cell cytoplasm with the nuclei remaining unlabelled. COX-2 expression was observed in five cases (17.2%) of normal follicular cells and in one case (16.6%) of solid cell nests. Follicular carcinoma expressed COX-2 more frequently than follicular adenoma (93.4% vs 21.1%) (p<or=0.001). A higher percentage of cases of papillary microcarcinomas up-regulated COX-2 in comparison with all papillary carcinomas (p<or=0.05). However, we could not establish any relationships among COX-2, patients' ages or lymph node metastases in papillary carcinomas. COX-2 expression was found in 12 (92.3%) poorly differentiated carcinomas and in 13 (92.8%) undifferentiated carcinomas. We found that COX-2 is not always useful as a marker of malignancy. Our results suggest that COX-2 plays a role in progression of all thyroid carcinomas, but in papillary carcinomas, seems more important only in the early stages. COX-2 expression in the undifferentiated carcinoma deserves special consideration due to its prognosis and to the fact that selective COX-2 inhibitors were found to enhance tumour response to radiation in some studies.