Neuroendocrine differentiation in carcinoma of the breast. Tyramide signal amplification discloses chromogranin A-positive tumour cells in more breast tumours than previously realized

Correctly identifying the cells of origin is essential for tailoring treatment and understanding the emergence of cancer stem cells and late metastases

Malignancy manifests itself by deregulated growth and the ability to invade surrounding tissues or metastasize to other organs. These properties are due to genetic and/or epigenetic changes, most often mutations. Many aspects of carcinogenesis are known, but the cell of origin has been insufficiently focused on, which is unfortunate since the regulation of its growth is essential to understand the carcinogenic process and guide treatment. Similarly, the concept of cancer stem cells as cells having the ability to stop proliferation and rest in a state of dormancy and being resistant to cytotoxic drugs before "waking up" and become a highly malignant tumor recurrence, is not fully understood. Some tumors may recur after decades, a phenomenon probably also connected to cancer stem cells. The present review shows that many of these questions are related to the cell of origin as differentiated cells being long-term stimulated to proliferation.

Utility of chromogranin B compared with chromogranin A as a biomarker in Japanese patients with pancreatic neuroendocrine tumors

Objective

Currently, serum chromogranin A is a well-established biomarker for pancreatic neuroendocrine tumors; however, other pancreatic diseases, oral use of a proton pump inhibitor and renal impairment can affect chromogranin A. Meanwhile, chromogranin B, belonging to the same granin family as chromogranin A, is not fully examined in these conditions. The present study aimed to evaluate the utility of chromogranin B as a pancreatic neuroendocrine tumor biomarker.

Methods

Serum chromogranin B levels were determined by radioimmunoassay and serum chromogranin A levels by enzyme-linked immunosorbent assay in pancreatic neuroendocrine tumor (n = 91) and other pancreatic conditions, and in healthy people (n = 104), to assess the relationships with clinical features.

Results

The diagnostic ability of chromogranin B was as good as chromogranin A. The area under the curve was 0.79 for chromogranin B (sensitivity/specificity: 72%/77%), and 0.78 for chromogranin A (sensitivity/specificity: 79%/64%). Chromogranin B was not affected by proton pump inhibitor use and age, which affected chromogranin A. The number of cases without liver metastases was larger in pancreatic neuroendocrine tumor patients with positive chromogranin B and negative chromogranin A. Though chromogranin A significantly elevated cases with proton pump inhibitor treatment and had positive correlation with age, chromogranin B did not have the tendencies. However, both chromogranin B and chromogranin A elevated in the case with renal impairment. In addition, the logistic regression analysis showed that chromogranin B was superior to chromogranin A in differentiation of pancreatic neuroendocrine tumor from other pancreatic diseases.

Conclusions

Compared with chromogranin A, chromogranin B may be more useful during proton pump inhibitor treatment and can detect tumors without liver metastases. In addition, chromogranin B may be an excellent biomarker when differentiation of pancreatic neuroendocrine tumor from other pancreatic diseases is required.

Neuron-Specific Enolase as an Immunohistochemical Marker Is Better Than Its Reputation

The diagnosis of neuroendocrine neoplasms (NENs) may be challenging and is based on typical morphological features and positive staining for antibodies of neuroendocrine differentiation. Neuron-specific enolase (NSE) being a cytosolic marker may be useful in this setting. NSE is by many considered nonspecific, due to the finding of this marker in tumors considered not to be of neuroendocrine origin. Our aim was to determine whether this is true and whether NSE is more specific than previously realized. We examined 178 tumors (carcinomas and NENs) from breast, lung, stomach, and kidney using immunohistochemistry with the following markers: chromogranin A, synaptophysin, CD56, secretagogin, and NSE. Expression of NSE was compared with that of the other markers. NSE was expressed in 138 (78%) of all tumors. Of the NSE-expressing tumors, 95 (68%) cases expressed one or more additional neuroendocrine markers. The staining intensity and number of NSE-expressing tumor cells were highest among tumors of neuroendocrine origin and clear cell renal cell carcinomas. A positive association was found between NSE expression and the number of additional neuroendocrine markers expressed in each of the tumors. Practically all tumors positive for an accepted neuroendocrine marker also expressed NSE.

A novel colorimetric immunoassay utilizing the peroxidase mimicking activity of magnetic nanoparticles

A simple colorimetric immunoassay system, based on the peroxidase mimicking activity of Fe3O4 magnetic nanoparticles (MNPs), has been developed to detect clinically important antigenic molecules. MNPs with ca. 10 nm in diameter were synthesized and conjugated with specific antibodies against target molecules, such as rotaviruses and breast cancer cells. Conjugation of the MNPs with antibodies (MNP-Abs) enabled specific recognition of the corresponding target antigenic molecules through the generation of color signals arising from the colorimetric reaction between the selected peroxidase substrate, 3,3',5,5'-tetramethylbenzidine (TMB) and H2O2. Based on the MNP-promoted colorimetric reaction, the target molecules were detected and quantified by measuring absorbance intensities corresponding to the oxidized form of TMB. Owing to the higher stabilities and economic feasibilities of MNPs as compared to horseradish peroxidase (HRP), the new colorimetric system employing MNP-Abs has the potential of serving as a potent immunoassay that should substitute for conventional HRP-based immunoassays. The strategy employed to develop the new methodology has the potential of being extended to the construction of simple diagnostic systems for a variety of biomolecules related to human cancers and infectious diseases, particularly in the realm of point-of-care applications.

The clinical relevance of chromogranin A as a biomarker for gastroenteropancreatic neuroendocrine tumors

Chromogranin A, although it exhibits limitations, is currently the most useful general tumor biomarker available for use in the diagnosis and management of gastroenteropancreatic neuroendocrine tumors (NETs). The value of the chromogranin A lies in its universal cosecretion by the majority of neuroendocrine cells that persists after malignant transformation. Clinicians aware of the physiologic role of chromogranin A and its secretion in a variety of non-NET-related pathologic conditions can use this protein as a moderately effective tumor biomarker in the management of GEP-NETs.

Neuroendocrine cells in diffuse gastric carcinomas: an ultrastructural study with immunogold labeling of chromogranin A

Neuroendocrine differentiation is often found in gastric carcinomas, but the relevance of these cells in gastric carcinogenesis is debated. We applied immunolabeling at the electron microscopic level to study the ultrastructure of neuroendocrine cells in gastric carcinomas to ensure correct cellular classification of dedifferentiated cells. The immunogold labeling at electron microscopic level was compared with an established sensitive immunohistochemical method using light microscopy. Thirteen human gastric adenocarcinomas of the diffuse type were examined for neuroendocrine differentiation by chromogranin A (CgA) labeling at both the light and electron microscopic level. The ultrastructure of CgA-positive cells was compared with CgA-positive cells from controls. Nine of 13 tumors showed CgA-positive cells both at the light and electron microscopic level. The CgA-positive cells displayed altered ultrastructural features compared with controls. Some of the CgA-positive tumor cells had granules typical for enterochromaffin-like cells. Immunoelectron microscopy seems to provide both significant immunolabeling and sufficient ultrastructure to enhance classification of cells in neoplastic tissue.

Chromogranin A--biological function and clinical utility in neuro endocrine tumor disease

BACKGROUND

Neuroendocrine tumors (NETs) are a form of cancer that differ from other neoplasia in that they synthesize, store, and secrete peptides, e.g., chromogranin A (CgA) and amines. A critical issue is late diagnosis due to failure to identify symptoms or to establish the biochemical diagnosis. We review here the utility of CgA measurement in NETs and describe its biological role and the clinical value of its measurement.

METHODS

Literature review and analysis of the utility of plasma/serum CgA measurements in NETs and other diseases.

RESULTS

CgA is a member of the chromogranin family; its transcription and peptide processing are well characterized, but its precise function remains unknown. Levels are detectable in the circulation but vary substantially (approximately 25%) depending on which assay is used. Serum and plasma measurements are concordant. CgA is elevated in approximately 90% of gut NETs and correlates with tumor burden and recurrence. Highest values are noted in ileal NETs and gastrointestinal NETs associated with multiple endocrine neoplasia type 1. Both functioning and nonfunctioning pancreatic NETs have elevated values. CgA is more frequently elevated in well-differentiated tumors compared to poorly differentiated NETs. Effective treatment is often associated with decrease in CgA levels. Proton pump inhibitors falsely increase CgA, but levels normalize with therapy cessation.

CONCLUSIONS

CgA is currently the best available biomarker for the diagnosis of NETs. It is critical to establish diagnosis and has some utility in predicting disease recurrence, outcome, and efficacy of therapy. Measurement of plasma CgA is mandatory for the effective diagnosis and management of NET disease.

Granins and granin-related peptides in neuroendocrine tumours

This review focus on neuroendocrine tumours (NETs), with special reference to the immunohistochemical analysis of granins and granin-related peptides and their usefulness in identifying and characterizing the great diversity of NET types. Granins, their derived peptides, and complex protein-processing enzyme systems that cleave granins and prohormones, have to some extent cell-specific expression patterns in normal and neoplastic NE cells. The marker most commonly used in routine histopathology to differentiate between non-NETs and NETs is chromogranin (Cg) A, to some extent CgB. Other members of the granin family may also be of diagnostic value by identifying special NET types, e.g. secretogranin (Sg) VI was only found in pancreatic NETs and phaeochromocytomas. SgIII has recently arisen as an important NET marker; it was strongly expressed in NETs, with some exceptions--phaeochromocytomas expressed few cells and parathyroid adenomas none. Some expression patterns of granin-related peptides seem valuable in differentiating between some benign and malignant NETs, some may also provide prognostic information, among which: well-differentiated NET types expressed more CgA epitopes than the poorly differentiated ones, except insulinomas, where the opposite was noted; medullary thyroid carcinomas containing few cells immunoreactive to a CgB antibody were related to a bad prognosis; C-terminal secretoneurin visualized a cell type related to malignancy in phaeochromocytomas. Further research will probably establish new staining patterns with marker functions for granins in NETs which may be of histopathological diagnostic value.

Immunohistochemical expression of estrogen and progesterone receptors in primary pulmonary neuroendocrine tumors

CONTEXT

Lung and breast carcinomas are among the most prevalent cancers. Advances in cancer therapies can provide survival benefit and be potentially curative, even in metastatic disease. Due to the high prevalence of these carcinomas, it is not unusual to encounter lung nodule(s) in a patient with breast carcinoma, and distinguishing between primary and metastatic disease is critical for management/treatment. Occasionally neuroendocrine differentiation is present in breast carcinoma, making its distinction from pulmonary/nonpulmonary neuroendocrine tumors in the lung difficult.

OBJECTIVE

To assess estrogen and progesterone receptor expression in the entire spectrum of pulmonary neuroendocrine tumors.

DESIGN

Seventy-one neuroendocrine neoplasms including typical carcinoids (42), atypical carcinoids (7), small cell carcinomas (14), large cell neuroendocrine carcinomas (2), and combined small cell carcinomas (6) were evaluated for estrogen and progesterone receptors. Mammary and non-small cell lung carcinomas were also stained for comparison.

RESULTS

The entire spectrum of neuroendocrine neoplasms demonstrated focal to diffuse estrogen (typical carcinoid, 23; atypical carcinoid, 6; small cell carcinoma, 8; large cell neuroendocrine carcinoma, 2; combined small cell carcinoma, 4) and progesterone (typical carcinoid, 11; atypical carcinoid, 2; small cell carcinoma, 7; large cell neuroendocrine carcinoma, 0; combined small cell carcinoma, 2) expression. There was no correlation between sex and estrogen/progesterone status. Estrogen and progesterone staining were also noted in endothelial cells. Relative to neuroendocrine carcinomas, mammary carcinomas expressed estrogen and progesterone more frequently. Non-small cell carcinomas had greater and similar immunoreactivity for estrogen and progesterone, respectively.

CONCLUSIONS

Although estrogen and progesterone receptor staining is frequently associated with breast and gynecologic primaries, it can also be observed in "nontarget" organs. Therefore, presence of estrogen and/or progesterone expression in neuroendocrine tumors involving the lung should not exclude a primary pulmonary neoplasm.

Prognostic value of circulating chromogranin A and soluble tumor necrosis factor receptors in advanced nonsmall cell lung cancer

BACKGROUND

Increased levels of chromogranin A (CgA), a protein secreted by many neuroendocrine cells, have been detected in sera of patients with neuroendocrine tumors or renal, hepatic, or heart failure. In patients with heart failure, serum CgA correlates with tumor necrosis factor-alpha (TNF) and soluble TNF receptors (sTNF-Rs), with important prognostic implications. The prognostic value of CgA and sTNF-Rs was investigated in advanced nonsmall cell lung cancer (NSCLC), a histologically heterogeneous group of tumors that may undergo neuroendocrine differentiation.

METHODS

CgA and sTNF-Rs were analyzed in the sera of 88 patients with NSCLC before chemotherapy by enzyme-linked immunoadsorbent assay (ELISA) and in tumors by immunohistochemistry.

RESULTS

Thirteen percent of patients had CgA values greater than the highest value observed in normal subjects (distribution range, 9-724 ng/mL and 28-196 ng/mL, respectively). Immunohistochemical studies showed no correlation between CgA expression in tumors and serum levels. Conversely, circulating CgA was associated with worse Eastern Cooperative Oncology Group (ECOG) performance status (PS) (P = .0005), more advanced stage (P = .042), and survival, with CgA being an independent prognostic factor of poor outcome (hazards ratio [HR] 1.31 for 100 ng/mL increase; 95% confidence interval [95% CI], 1.08-1.60 [P = .0071]). sTNF-R1 and sTNF-R2 were also associated with ECOG PS (P = .0001 and P = .02, respectively). sTNF-Rs was weakly correlated with circulating CgA (r = 0.39 for TNF-R1 and r = 0.40 for TNF-R2), suggesting a regulatory link between sTNF-Rs and CgA secretion.

CONCLUSIONS

Increased serum levels of CgA in NSCLC are independent from protein expression in tumors and more likely related to neuroendocrine response associated with worsening of patient condition. In addition to ECOG PS and stage, CgA is an independent indicator of poor prognosis.

Expression of neuroendocrine markers in non-small cell lung cancer

Neuroendocrine (NE) differentiation is reported in some cases of non-small cell lung cancer (NSCLC). The aim of this study was to evaluate the expression of NE markers in NSCLC using novel sensitive methods. 20 cases of NSCLC were examined using immunohistochemical (IHC) and immunoelectron microscopy (IEM) methods. In addition, circulating levels of the NE markers chromogranin A (CgA) and neuron-specific enolase (NSE) were measured. Using conventional IHC methods, two tumours (10%) showed immunoreactivity for synaptophysin (SYN), one (5%) for Cg and four (20%) for neural cell adhesion molecule (NCAM). Adding the tyramide signal amplification (TSA) technique, the number of immunoreactive tumours for both SYN and CgA increased to five (25%). No increased immunoreactivity was achieved for NCAM. Nine tumours (45%) were immunoreactive for SYN, CgA or NCAM. Using IEM, one of five representative samples that revealed IHC reactivity for CgA showed immunogold labelling of CgA in cytoplasmic vesicles. Elevated levels of circulating CgA or NSE did not correlate with positive IHC findings. In conclusion, using sensitive IHC methods NE differentiation was seen in a greater proportion of NSCLC than previously reported. Sensitive methods may improve our understanding of the tumour biology and represent an important diagnostic tool for future therapeutic modalities.

Genes involved in neuroendocrine tumor biology

The fascinating, but often unpredictable, biology of neuroendocrine tumors (NETs) make the management of these malignancies a real challenge. The more recent development of high-throughput genomic and proteomic techniques, have opened a window to an increased knowledge of the biology of NETs. This review will discuss genes thought to play a role in the context of NE tumor biology, with particularly attention to those that may be potential new diagnostic and prognostic markers, as well as therapeutic targets. NETs constitute a heterogeneous group of neoplasm that may arise in virtually every topographic localization in the body, as a consequence of malignant transformation of various types of NE cells. Since NETs arising in the gastroenteropancreatic (GEP) or bronchopulmonary system are by far the most common, this review focuses on these entities, but lines are drawn to other NETs as well. Although large-scale gene expression analysis undoubtly have raised interesting new hypothesis concerning genes thought to play a role in tumor biology, discrepancies observed between studies and various platforms used, emphasizes the need to not only standardize the way microarray data are reported, but also to introduce standards in sample taking, processing and study design. In addition, the recognition of the complexity of the human proteome, with regard to generation of multiple isoforms from one gene, has created additional challenges. However,some goals have been reached already, as new knowledge has been translated into development of novel promising therapeutics.