Chromogranin-A as a Serum Marker for Neuroendocrine Tumors: Comparison with Neuron-Specific Enolase and Correlation with Immunohistochemical Findings

Role of the ratio of NSE serum concentration in evaluating the therapeutic effect on metastatic neuroendocrine neoplasms of the liver

BACKGROUND

Neuron-specific enolase (NSE) is one of the biomarkers of neuroendocrine neoplasms (NEN). Its level of evidence is significantly lower than some other biomarkers. However, the ratio of NSE serum concentration (NSE ratio) before and after the treatment cycle may be a good tool for evaluating the therapeutic effect of metastatic neuroendocrine neoplasms of the liver (MNENOL).

METHODS

We collected clinical cases of NEN with liver metastases, calculating the ratio of NSE in each case before and after the treatment cycle, using thin-slice computed tomography or magnetic resonance imaging as a reference to evaluate the therapeutic effect. We analyzed the correlation between NSE ratio and NSE serum concentration and curative effect, and then compared the evaluation performance of the two.

RESULTS

We found that increase in the NSE ratio is a risk factor for the progression of MNENOL. Compared with NSE, NSE ratio has a greater advantage in evaluating the effect of MNENOL. NSE ratio is related to the curative effect of NEN, and the correlation is better than that of NSE. When judging whether NEN has new metastasis, the NSE ratio shows a similar effect to NSE, and there is no significant difference between the two.

CONCLUSION

NSE ratio is more effective than NSE in evaluating the therapeutic effect of MNENOL, but it is not significantly different from NSE in terms of predicting new metastases.

Inherited and acquired clinical phenotypes associated with neuroendocrine tumors

PURPOSE OF REVIEW

Overview of neuroendocrine neoplasms in the context of their associations with primary and secondary immunodeficiency states.

RECENT FINDINGS

Malignancies of neuroendocrine origin are well known to be associated with hereditary syndromes, including multiple endocrine neoplasia type 1, von Hippel-Lindau syndrome, neurofibromatosis type 1, and tuberous sclerosis. This review includes the X-linked form of hyper-IgM syndrome (XHIGM), due to mutations in the CD40Ligand gene (CD40LG), as an additional inherited disorder with susceptibility to such malignancies, and discusses neuroendocrine tumors (NETs) arising in other immunocompromised states. Of all primary immune deficiency diseases, NETs appear to be unique to XHIGM patients. Outcomes for XHIGM patients with NETs is poor, and the mechanism behind this association remains unclear. In secondary immune deficiency states, NET occurrences were primarily in patients with HIV or AIDS, the autoimmune disease systemic lupus erythematosus and solid organ transplant recipients. Gastroenteropancreatic NETs were most frequent in XHIGM patients, whereas nongastroenteropancreatic-NETs, like Merkel cell carcinoma and small-cell lung carcinoma, affected HIV/AIDS patients. Possible mechanisms as to the nature of these associations are discussed, including chronic infections and inflammation, and CD40-CD40L interactions. Many questions remain, and further studies are needed to clarify the predisposition of patients with XHIGM to the development of NETs. Given that many of these patients present late in their disease state and have poor outcomes, it is imperative to keep a high index of suspicion at the advent of early signs and symptoms. Regular monitoring with laboratory or imaging studies, including tumor markers, may be warranted, for which further studies are needed.

SUMMARY

Of all primary immunodeficiency diseases, NETs appear to be unique to XHIGM, and the mechanism behind this association remains unclear. Outcome for XHIGM patients with NETs is poor, and it is imperative to keep a high index of suspicion at the advent of early signs and symptoms.

Evaluation of Chromogranin a Expression in Serum and Tissues of Breast Cancer Patients

Human chromogranin A (CgA) is a member of the granin family and is widely distributed in large dense core granules of endocrine and neuroendocrine cells. A variety of non-neuroendocrine carcinomas arising in various tissues show patterns of neuroendocrine differentiation. Expression of CgA has been documented in epithelial cells of normal mammary gland as well as in breast cancers, and elevation of serum CgA has been detected in patients with breast cancer. Our study was undertaken to evaluate the relationship between serum CgA levels and neuroendocrine features in breast cancer. In addition, we evaluated the expression of serum CgA in patients affected by breast cancer compared to controls and the relationship between serum CgA and tumor histology, extent of disease, lymph node status, tumor stage and serum CA 15.3 levels. We enrolled 266 patients with infiltrating ductal or lobular breast carcinoma and a group of 100 age-matched healthy women serving as controls. Serum CgA and CA 15.3 were assayed by specific immunoradiometric methods. The overall sensitivity of CgA and CA 15.3 was 0.06 and 0.34, respectively (χ219.1, p<0.0005). No relationship was found between serum levels of CgA and tumor histology, extent of disease, lymph node status or tumor stage while serum levels of CA 15.3 were strongly correlated with all these variables but tumor histology. No relationship was found between serum levels of CgA and CA 15.3. Immunostaining against CgA, CgB, NSE and synaptophysin was performed on primary tumor tissue of 14 serum CgA-positive and 24 serum CgA-negative patients and was negative in all cases. We also evaluated eight cases of pathologically-proven neuroendocrine breast cancer: only four and two of these showed positive CgA immunostaining and increased serum CgA concentration, respectively. In conclusion, serum CgA assay offers no additional information regarding the presence, the extent and the histology of breast cancer compared to the CA 15.3 assay. Moreover, serum CgA was not an accurate marker to identify or exclude the rare neuroendocrine differentiation of breast cancer. We therefore conclude that CgA is not useful as a serum marker in breast cancer.

Immunoradiometric Assay of Chromogranin a in the Diagnosis of Small Cell Lung Cancer: Comparative Evaluation with Neuron-Specific Enolase

The aims of our work were 1) to determine the diagnostic performance of an immunoradiometric assay of chromogranin A (CgA) in smal cell lung cancer and 2) to compare its discriminatory power with that of neuron-specific enolase (NSE), the marker currently used for SCLC. We selected 166 cases of small cell (64) and non-small cell (102) lung cancer and 106 cases of non-malignant lung diseases as controls. Both CgA and NSE were assayed by immunoradiometric methods and cutoff values were established on the basis of a pre-fixed specificity of 95% in non-malignant lung diseases. The CgA assay showed better diagnostic sensitivity than NSE in SCLC (61% versus 57%), especially in limited disease, and a low positivity rate in NSCLC with respect to NSE (14% versus 22%). By contrast, NSE reflected disease extent more accurately than CgA (U test: CgA p<0.05, NSE p<0.001). Finally, we found that the CgA assay was not affected by hemolysis whereas NSE serum levels greatly increased in hemolyzed sera. In conclusion, CgA assaying by an IRMA method is a reliable procedure in the diagnosis of SCLC. NSE remains the marker of choice in staging and monitoring of the disease. Further studies are needed to evaluate the prognostic significance of the marker and its role in therapy monitoring and patient follow-up.

The value of serum chromogranin A as a predictor of tumor burden, therapeutic response, and nomogram-based survival in well-moderate nonfunctional pancreatic neuroendocrine tumors with liver metastases

OBJECTIVE

To investigate the usefulness of serum chromogranin A (CgA) for the prediction of tumor burden, therapeutic response, and nomogram-based survival in well-moderate nonfunctional pancreatic neuroendocrine tumors (NF-PNETs) with liver metastases (LMs).

MATERIALS AND METHODS

This prospective study included 51 NF-PNETs of LMs patients, 134 other neuroendocrine tumors, and 125 controls. Serum CgA levels were determined by enzyme-linked immunosorbent assay at baseline and after treatment. LMs tumor burden was computed simultaneously from computed tomography/MRI scan with thin slices using a semiquantitative three-dimensional reconstruction approach. Predictive CgA for therapeutic response was assessed using the response evaluation criteria in solid tumors criteria. A nomogram to predict the prognostic value of CgA with variables selected in the multivariate Cox proportional hazards model was constructed; the accuracy of the nomogram was quantified by the (concordance index) C-index and a calibration plot.

RESULTS

Considering NF-PNETs, CgA correlated with the tumor grade and differentiation (P<0.05). There was a nonlinear exponential regression between LMs tumor burden and CgA levels (P<0.001). The alteration in CgA correlated with therapeutic response (P<0.001). Increased CgA presented significantly lower progression-free survival than the stable/decreased CgA subgroup (P<0.001). For overall survival, a baseline CgA increase greater than 2.5 upper limit of normal level was predictive of a poor prognosis (P<0.001). Baseline CgA level, LMs tumor burden, and Ki-67 were selected as independent factors for the nomogram to predict overall survival; the nomogram showed fitting calibration with a C-index of 0.87 (95% confidence interval, 0.82-0.92).

CONCLUSION

Serum CgA could be used to reflect tumor burden, evaluate the therapeutic response, and predict the survival outcomes for NF-PNETs with LMs. An effective nomogram including CgA was proposed for prediction.

Is the combination of chromogranin A and pancreatic polypeptide serum determinations of interest in the diagnosis and follow-up of gastro-entero-pancreatic neuroendocrine tumours?

INTRODUCTION

Chromogranin A (CgA) is the principal tumour marker for gastroenteropancreatic neuroendocrine tumours (GEPNET). Combining serum CgA and pancreatic polypeptide (PP) levels may increase the sensitivity of tumour markers in the diagnosis of GEPNET.

OBJECTIVES

(1) To evaluate the sensitivity of PP and CgA in GEPNET. (2) To compare changes in serum CgA and PP levels with the morphological evolution of the tumours.

PATIENTS AND METHODS

Sixty-six pancreatic and 49 gastrointestinal NET, with at least one serum determination of CgA and PP at the same time were retrieved from an institutional data base. Secondly, the variations in serum CgA or PP at successive determinations were compared to Response Evaluation Criteria in Solid Tumours (RECIST) criteria in 57 patients (112 follow-up visits) with high serum CgA levels and in 21 patients (37 follow-up visits) with high serum PP levels.

RESULTS

Among the 115 patients included in the study group, an increase in serum CgA (normal <98 μg/L) or PP (normal <100 pmol/L) was found in respectively 79 (69%) and 36 (31%) cases. Seven patients had normal CgA and elevated PP levels. Both markers were significantly more elevated in metastatic disease (74% versus 51% for CgA and 37% versus 18% for PP). The concordance rates between serum markers and RECIST criteria were 51% for CgA and 54% for PP.

CONCLUSIONS

Serum PP determination identify few false-negative results of serum CgA determination in GEPNET. Our study does not validate the use of CgA or PP as surrogate markers for detecting changes in tumour burden.

Choice of tumour markers in patients with neuroendocrine tumours is dependent on the histological grade. A marker study of Chromogranin A, Neuron specific enolase, Progastrin-releasing peptide and cytokeratin fragments

BACKGROUND

Chromogranin A (CgA) is the most important tumour marker for well-differentiated neuroendocrine tumours (NET) and neuron specific enolase (NSE) for poorly differentiated neuroendocrine carcinoma (NEC). This study investigated whether the markers progastrin-releasing peptide (proGRP) and cytokeratin fragments (CKfr) CK8, CK18 and CK19 (MonoTotal) can be of additional value to the histological classification and help predict survival in these patients.

METHODS

CgA, NSE, proGRP and CKfr were measured in 242 patients with grade 1 NET (G1NET), 38 with grade 2 NET (G2NET), 42 with large cell NEC (LCNEC), 251 with small cell NEC (SCNEC) and in 282 healthy persons. Results were compared with tumour characteristics and survival by means of Receiver Operating Characteristics (ROC) curves and Cox regression analyses.

RESULTS

The largest area under the ROC curve was for CgA (0.86, 0.91 and 0.90, respectively) when comparing patients with G1NET, G2NET and LCNEC with healthy persons. ProGRP showed the highest sensitivity (73%) at 95% specificity in patients with SCNEC. In a multivariate survival analysis, only CKfr was associated with survival (P<0.0001) for patients with well-differentiated NET (G1NET and G2NET). For patients with poorly differentiated NEC, both CKfr and NSE were associated with survival (P<0.0001 and P=0.003, respectively).

CONCLUSION

Within all histological groups a combination of tumour markers proved to be more informative as diagnostic and prognostic marker than each marker alone. In patients with well-differentiated NET and LCNEC we recommend the use of CgA and CKfr, whilst in patients with SCNEC, proGRP and CKfr are preferred.

Regulation of gastric hormones by systemic rapamycin

The mammalian target of rapamycin (mTOR), an evolutionarily conserved serine-threonine kinase, is an intracellular fuel sensor critical for cellular energy homeostasis. Gastrointestinal endocrine cells play a vital role in the regulation of energy balance by secreting hormones that inform the brain about energy supply. Here we showed the localization of mTOR signaling molecules in more than 90% of gastric ghrelin cells and 36±3% of gastrin cells, while no somatostatin-positive cell showed phospho-S6K1 immunoreactivity. Inhibition of mTOR significantly stimulated expression of gastric ghrelin mRNA and protein, and the concentration of plasma ghrelin (2.06±0.34 ng/ml vs. 12.53±3.9 ng/ml, p<0.05), inhibited gastrin synthesis and secretion (75.01±6.71 pg/ml vs. 54.04±3.65 pg/ml, p<0.05), but had no effect on somatostatin production (165.2±25.07 pg/ml vs. 178.9±29.14 pg/ml, p=0.73). Gastric mTOR is a gastric sensor whose activity is linked to the differential regulation of gastric hormone production and release.

Chromogranin-A and N-terminal pro-brain natriuretic peptide: an excellent pair of biomarkers for diagnostics in patients with neuroendocrine tumor

PURPOSE

For the last decade chromogranin-A (CgA) has been a well-established marker for neuroendocrine tumor (NET), and N-terminal pro-brain natriuretic peptide (NT-proBNP) has been a useful marker for left ventricular dysfunction. This study examined the diagnostic value of CgA and NT-proBNP for carcinoid heart disease (CHD), and their prognostic value for overall survival in NET patients.

PATIENTS AND METHODS

Serum samples were obtained and cardiac ultrasound studies performed in 102 NET patients. The criterion for mild and severe CHD was tricuspid regurgitation stage I/II and III/IV, respectively. Proportional odds and Cox proportional hazards models were constructed respectively to identify the association between CHD and overall survival with patient characteristics and the two markers.

RESULTS

Severe CHD was found in 15 (15%) of 102 patients, 13 of whom had elevated NT-proBNP levels. In the univariate proportional odds model CHD was correlated with age (P = .007), CgA (P = .002), and NT-proBNP (P < .001), whereas in the multivariate model NT-proBNP and CgA were significantly associated with CHD (P < .001 and P = .01). In the univariate Cox models, age (P = .04), sex (P = .03), CgA (P = .003), and NT-proBNP (P = .04) were related to overall survival, and in the multivariate model CgA and NT-proBNP remained significantly related to overall survival (P = .002 and P = .04, respectively).

CONCLUSION

NT-proBNP and CgA are very important markers in the diagnosis of CHD in patients with NET. Furthermore, patients with elevated NT-proBNP in addition to elevated CgA levels showed worse overall survival than patients with elevated CgA alone.

Prognostic value of chromogranin A at admission in critically ill patients: a cohort study in a medical intensive care unit

BACKGROUND

Risk assessments of patients should be based on objective variables, such as biological markers that can be measured routinely. The acute response to stress causes the release of catecholamines from the adrenal medulla accompanied by chromogranin A (CGA). To date, no study has evaluated the prognostic value of CGA in critically ill intensive care unit patients.

METHODS

We conducted a prospective study of intensive care unit patients by measuring serum procalcitonin (PCT), C-reactive protein (CRP), and CGA at the time of admission. Univariate and multivariate analyses were performed to evaluate the ability of these biomarkers to predict mortality.

RESULTS

In 120 consecutive patients, we found positive correlations between CGA and the following: CRP (r(2) = 0.216; P = 0.02), PCT (r(2) = 0.396; P < 0.001), Simplified Acute Physiologic Score II (SAPS II) (r(2) = 0.438; P < 0.001), and the Logistic Organ Dysfunction System (LODS) score (r(2) = 0.374; P < 0.001). Nonsurvivors had significantly higher CGA and PCT concentrations than survivors [median (interquartile range): 293.0 microg/L (163.5-699.5 microg/L) vs 86.0 microg/L (53.8-175.3 microg/L) for CGA, and 6.78 microg/L (2.39-22.92 microg/L) vs 0.54 microg/L (0.16-6.28 microg/L) for PCT; P < 0.001 for both comparisons]. In a multivariable linear regression analysis, creatinine (P < 0.001), age (P < 0.001), and SAPS II (P = 0.002) were the only significant independent variables predicting CGA concentration (r(2) = 0.352). A multivariate Cox regression analysis identified 3 independent factors predicting death: log-normalized CGA concentration [hazard ratio (HR), 7.248; 95% confidence interval (CI), 3.004-17.487], SAPS II (HR, 1.046; 95% CI, 1.026-1.067), and cardiogenic shock (HR, 3.920; 95% CI, 1.731-8.880).

CONCLUSIONS

CGA is a strong and independent indicator of prognosis in critically ill nonsurgical patients.

[Effective treatment of a hormonally inactive carcinoid tumour with somatostatin analogues: application of serum chromogranin-A for clinical follow-up]

INTRODUCTION

Hormonally inactive carcinoids represent a significant proportion of all carcinoids tumours. Classical biochemical and hormonal parameters are not suitable for the diagnosis and follow-up of these tumours. However, the tumour marker chromogranin A that is characteristic for several neuroendocrine tumours and secreted by the majority of these tumours as well, may offer a better means of diagnosis and follow-up. Somatostatin receptors are expressed by hormonally inactive carcinoids and the presence of these receptors has important diagnostic and therapeutic consequences.

CASE REPORT

The authors present the history of a patient with a hormonally inactive bronchial carcinoid tumour. After surgical removal of the bronchial carcinoid, liver metastases developed which were found to be somatostatin receptor positive. Somatostatin analogue treatment was introduced, followed by Yttrium-isotope labelled somatostatin analogue therapy. Serum chromogranin A was elevated before somatostatin treatment, and gradually decreased in parallel with therapy. The size of liver metastases remained unchanged during treatment.

CONCLUSIONS

Chromogranin A can be efficiently applied for the clinical follow-up of hormonally inactive carcinoid tumours. Somatostatin analogues may be effective for preventing tumour progression not only in hormone-secreting but also in hormonally inactive carcinoid tumours.

An Italian program of External Quality Control for chromogranin A (CgA) assay: performance evaluation of CgA determination

BACKGROUND

Chromogranin A (CgA) is an acidic glycoprotein produced by many neuroendocrine cells and neurons. Currently, two different methods for assaying CgA, immunoradiometric assay (IRMA) and enzyme-linked immunosorbent assay (ELISA), are widely used in routine practice. Within the framework of a Ministry of Health project, an External Quality Control program was developed to investigate the state of the art of CgA determination in Italy and to monitor the performance of laboratories carrying out this assay. This paper reports the results regarding laboratory performance.

METHODS

A total of 43 laboratories participated in this program, in which 21 used the ELISA method and 22 the IRMA method. Each laboratory received six samples, three aliquots of serum and three of plasma, at high, intermediate and low concentrations. The results provided by the two assay methods were analyzed separately using two statistical approaches, the principal component analysis and the control chart method.

RESULTS

For the IRMA method, questionable results for all samples were obtained by two laboratories, while in two other laboratories performance was questionable for only one sample. For the ELISA method, questionable performances were obtained in only one laboratory for the low and intermediate concentration samples, whereas in three laboratories performance was questionable for only one sample. Interestingly, the coefficients of variation increased approximately five-fold when shifting from the IRMA to the ELISA method.

CONCLUSIONS

This program demonstrated both the requirement and demand for external quality assessment of CgA assay.

Measurements of chromogranin B can serve as a complement to chromogranin A

OBJECTIVE

CgA has been shown to be an excellent marker for neuroendocrine tumours. However, there are two major drawbacks with CgA measurements; elevated levels are common in patients with decreased renal function and in patients on treatment with proton pump inhibitors. These problems are not seen with CgB measurements. We have recently presented the development of 13 region-specific radioimmunoassays for measurements of CgB. A region-specific assay was identified, which measured higher concentrations of CgB than the other assays and seemed to be very useful as a marker for neuroendocrine tumours. The aim of the present study was therefore to further explore the diagnostic potential of this assay in the clinical management of patients with neuroendocrine tumours.

METHODS

Measurements of CgB with two methods were compared with CgA in plasma samples from patients investigated for neuroendocrine tumours (N=86), patients with decreased renal function (N=35) and patients on treatment with proton pump inhibitors (N=29).

RESULTS

The diagnostic sensitivity for the new CgB assay was almost as good as that for CgA. Furthermore, with CgB measurements we could avoid the falsely elevated levels of CgA found in patients with decreased renal function and treatment with proton pump inhibitors.

CONCLUSIONS

We conclude that the new CgB assay can serve as a complement to CgA measurements as an important tumour marker for neuroendocrine tumours.

The prognostic significance of circulating neuroendocrine markers chromogranin a, pro-gastrin-releasing peptide and neuron-specific enolase in patients with advanced non-small-cell lung cancer

BACKGROUND

Chromogranin A (CGA), Pro-gastrin-releasing peptide (ProGRP) and neuron-specific enolase (NSE) are known as immunohistochemical tissue markers closely associated with neuroendocrine differentiation in non-small-cell lung carcinoma (NSCLC). The aim of the present study was to assess the value of serum levels of these markers in predicting response to chemotherapy and survival of patients with unresectable NSCLC.

METHODS

The study included 67 patients with advanced NSCLC treated with chemotherapy. Before treatment, serum levels of CGA, ProGRP and NSE were measured with commercial kits.

RESULTS

No association was found between serum NSE and age, gender, histology, performance status or extent of the disease. Distribution of serum CGA differed significantly according to gender and histology, with higher levels being found in men (p = 0.01) and in squamous cell carcinoma (p = 0.01). Serum ProGRP levels correlated with disease extent, being higher in patients with metastatic disease (M1) than in those with locoregional disease (M0; p = 0.02). The association of NSE, CGA and ProGRP levels with response to chemotherapy was not significant. While NSE had no impact on survival, the median survival was shorter for patients with elevated serum CGA and longer for patients with high ProGRP levels. Association with survival was significant when the Classification and Regression Tree (CART)-derived or median cutoff points were explored. On inclusion in multivariate Cox models, both CGA and ProGRP retained significance with high levels showing an opposite effect on survival [CART-derived cutoff points: CGA, relative risk (RR) -4.0; p < 0.001, and ProGRP, RR -0.4; p = 0.006, and median cutoff points: CGA, RR -1.8; p = 0.04, and ProGRP, RR -0.5; p = 0.03]. The combined use of CGA, ProGRP and NSE allowed for definition of two sets of patients with significantly different median survival times (25.2 vs. 8.8 months, p = 0.0001).

CONCLUSIONS

In the circulation, CGA and Pro-GRP appear to bear important information related to the prognosis for NSCLC patients before chemotherapy. While a high CGA before treatment was found as an unfavorable prognostic determinant, a high ProGRP conferred a survival advantage. The combined use of serum CGA, ProGRP and NSE may supply additional information to prognosis.

Chromogranin A as a determinant of midgut carcinoid tumour volume

Neuroendocrine (NE) tumours are characterized by their capacity to synthesize, store and release hormonal products. These substances are stored in neurosecretory vesicles together with chromogranin A (CgA). The concentration of plasma CgA in patients with NE tumours is thought to reflect the degree of NE differentiation, total tumour burden and effect of medical treatment. The aim of this study was to analyse the correlation between tumour weight and plasma CgA levels as well as the influence of treatment with a long-acting somatostatin analogue (octreotide) using nude mice with xenografted human ileal carcinoid tumours. There was a correlation between tumour weight and plasma CgA levels in all animals (p < 0.00001). In octreotide-treated mice, plasma CgA levels were significantly reduced versus untreated animals (p = 0.037). In conclusion, this study demonstrates that plasma CgA levels are closely correlated to tumour burden, and that plasma CgA is well suited for monitoring the clinical course and outcome of treatment in patients with NE tumours.

Interest of Chromogranin A for diagnosis and follow-up of endocrine tumours

OBJECTIVE

To determine the interest of Chromogranin A (CgA) determination for diagnosis and follow-up in patients with gastroenteropancreatic endocrine tumours (GEP-ET) and multiple endocrine neoplasia type 1 (MEN-1).

PATIENTS AND METHODS

CgA levels were measured with an immunoradiometric assay in 124 sporadic GEP-ET, 34 MEN-1 and 127 controls. Serial determinations were performed in 56 patients (212 visits). Changes in CgA levels over 25% were considered as significant.

RESULTS

Using a cut-off value of 130 micro g/l, established from a receiver-operating characteristic curve, the specificity of CgA was 98.4%, with a sensitivity of 62.9%, higher in secreting than in nonsecreting tumours (73%vs. 45%; P < 0.003) and related to the extent of metastatic spreading (P < 0.001). In nonsecreting tumours, the positive predictive value (PPV) of CgA for the presence of metastases was 100% but the negative predictive value (NPV) was only 50%. In MEN-1, high CgA levels indicated a pancreatic tumour with a 100% specificity but the sensitivity was 59%. During the follow-up, the concordance between CgA and tumour evolution was 80%, whatever the secretory status. In patients with carcinoid tumours, the concordance was higher for CgA than for serotonin (81%vs. 54%; P < 0.001).

CONCLUSION

Due to its high specificity, CgA determination may help to discriminate the endocrine character of a GEP tumour and to indicate a pancreatic tumour in MEN-1. However, its low NPV in nonsecreting tumours limits its interest for diagnosis and staging. By contrast, serial evaluation of CgA seems of particular interest for the follow-up of GEP-ET tumours.

Prospective study of the ability of serial measurements of serum chromogranin A and gastrin to detect changes in tumor burden in patients with gastrinomas

BACKGROUND

Assessment of tumor burden changes is essential for the management of patients with neuroendocrine gastrointestinal (GI) tumors. Chromogranin A (CgA) is a tumor marker for such tumors; however, to the authors' knowledge, there is little information on whether serial assessments can assess changes in tumor burden. In this prospective study of patients with gastrinomas, serial changes in serum CgA levels were compared with changes in levels of the specific tumor marker gastrin to determine whether they reflected changes in tumor burden.

METHODS

In 72 consecutive patients, the mean CgA and gastrin levels from three determinations were measured on each visit. Changes in markers were correlated with changes in tumor burden determined by imaging. By assessing daily changes, significance changes in CgA and gastrin levels were determined.

RESULTS

During 103 follow-up visits (mean, 9.6 months), an increased tumor size occurred in 25% of patients, no change occurred in 62% of patients, and a decrease occurred in 13% of patients. In patients who had increasing tumor size, CgA levels increased numerically in 77% of patients, gastrin levels increased in 54% of patients, and the increases were significant in 60-80% of patients. In patients who had tumor stabilization, CgA levels in 63% of patients and gastrin levels in 73% of patients did not show a significant change. Decreased tumor size postresection showed a significant decrease in CgA and gastrin levels in all patients. The sensitivity of CgA and gastrin was as follows: sensitivity for detecting an increase, 62% for CgA and 31% for gastrin; sensitivity for detecting no change, 42% for CgA and 75% for gastrin; and sensitivity for detecting a decrease in tumor size, 85% for CgA and 85% for gastrin. The specificity varied from 53% to 99% for CgA and from 49% to 93% for gastrin.

CONCLUSIONS

In patients with gastrinomas, serum CgA and gastrin levels varied considerably from day to day, and this must be taken into consideration. Both markers had low sensitivity and specificity for detecting tumor increases and stabilization. For large tumor decreases postresection, both markers had high sensitivity and specificity. The current results suggest that these markers do not have sufficient sensitivity to replace serial imaging studies for detecting important smaller changes in tumor burden in patients with gastrinomas.

Chromogranin 'A' in normal subjects, essential hypertensives and adrenalectomized patients

OBJECTIVE

Chromogranin A (CgA) is an acidic glycoprotein co-stored in vesicles and co-released with catecholamines. Although currently used as a humoral marker of endocrine tumours, several aspects of CgA secretion still need to be clarified in humans.

PATIENTS

Fifty-four controls, 83 essential hypertensive and six adrenalectomized patients were studied.

DESIGN

In the controls and hypertensive patients, CgA and catecholamines were measured before (supine position) and after changes in posture (2' upright position), insulin-induced hypoglycaemia (0.15 IU/kg i.v.) and glucagon injection (1 mg i.v.). In addition, blood samples were taken in the morning (0800 h) and in the afternoon (1800 h), and every 5 h for 24 h. In the adrenalectomized patients, blood samples were obtained in the morning and in the afternoon.

MEASUREMENTS

CgA was measured by an immunoradiometric assay, and noradrenaline and adrenaline by high-performance liquid chromatography.

RESULTS

In controls, posture slightly increased plasma catecholamines without affecting CgA levels. Hypoglycaemia evoked a rise in noradrenaline (P < 0.04), adrenaline (P < 0.01) and CgA (79.6 +/- 11.8 vs. 46.1 +/- 10.1 microg/l, P < 0.03). Glucagon injection increased plasma adrenaline (P < 0.01) but not noradrenaline or CgA levels. At variance with blood pressure and catecholamines, CgA increased significantly in the afternoon (51.1 +/- 4.0 vs. 45.0 +/- 3.9 microg/l, P < 0.05); it also had a circadian rhythm, with peak values during the night (at 2300 h, 65.4 +/- 9.0 microg/l) and a nadir in the morning (at 0800 h, 43.1 +/- 6.6 microg/l). In hypertensives, basal and stimulated CgA levels as well as diurnal/circadian variations of this peptide were similar to those in normal subjects. In adrenalectomized patients plasma CgA in the morning (34.3 +/- 6.5 microg/l) was lower (P < 0.03) than in all controls and hypertensives studied, but also showed an afternoon increment (46.4 +/- 6.6 microg/l, P < 0.003). No correlation was found between CgA and catecholamines or blood pressure in all subjects or in the subgroups.

CONCLUSIONS

In normal humans, chromogranin A and catecholamines are not always co-secreted, and co-secretion occurs only for marked exocytotic adrenergic stimuli, such as hypoglycaemic stress. In addition, chromogranin A has a circadian rhythm unrelated to plasma catecholamines. Basal plasma concentrations and the secretory pattern of chromogranin A in hypertensives do not differ from the findings in controls. Finally, the adrenal glands contribute partially to circulating chromogranin A and are not involved in the circadian rhythm of this peptide in humans.

Serum Chromogranin-A Immunoradiometric Assay in the Diagnosis of Pheochromocytoma

Background

The diagnosis of pheochromocytoma is based on laboratory tests that demonstrate an increase in urinary excretion of catecholamines or their metabolites. Chromogranin A (CgA) is a member of the granin family and is widely distributed in neuroendocrine cells and particularly in chromaffin adrenal cells. Consequently, serum CgA increases in patients affected by pheochromocytoma and other diseases of the chromaffin system.

Aim

This study investigated the performance of serum CgA assay in the diagnosis of pheochromocytoma and compared serum CgA with 24-hour urinary epinephrine (E), norepinephrine (NE), vanillylmandelic acid (VMA) and metanephrines (MNs).

Methods

We enrolled 15 patients with histologically proven pheochromocytoma; 100 healthy blood donors and 148 patients with essential hypertension were enrolled as controls. Serum CgA was assayed by a specific immunoradiometric method (IRMA). Urinary tests were done with high performance liquid chromatography (HPLC).

Results

Circulating CgA showed a higher sensitivity (1.00), specificity (0.96) and accuracy (0.96) than all other tests. Serum levels of CgA clearly increased from blood donors and patients with essential hypertension to patients with pheochromocytoma (p<0.0001). Furthermore, a strong relationship between serum CgA and tumor mass was found (p<0.0001). In conclusion, our data suggest that the CgA assay might be used as a single test for the diagnosis of pheochromocytoma.

Clinical significance of neuroendocrine carcinoma of the breast

BACKGROUND

Neuroendocrine (NE) carcinomas of the breast are defined by the diffuse expression of NE markers. This definition includes lesions with 'pure' NE phenotype as well as 'variants' which may co-express mucinous and/or apocrine phenotype. In the present work, the clinical significance of pure' NE differentiation in breast carcinoma and of its 'variants' will be analyzed.

MATERIALS AND METHODS

Forty-three NE breast carcinomas immunocytochemically positive for chromogranins and/or synaptophysin in > or = 50% of cells were graded following the Elston and Ellis grading system for breast carcinomas. The production of mucin and the expressionof the apocrine marker Gross Cystic Disease Fluid Protein-15 (GCDFP-15) were correlated with the grade and the hormonal receptor status. The clinical outcome of patients was also analyzed.

RESULTS

The histological grade highly influenced the clinical evolution of NE breast carcinomas. We confirmed that mucinous differentiation is an important indicator of low biological aggressiveness. Estrogen and progesterone receptor expression was also correlated with a better prognosis. Presence of androgen was correlated with the expression of GCDFP-15 in NE tumors.

CONCLUSIONS

The histological grade overcomes the immunophenotype in determining the prognosis of NE differentiated carcinomas of the breast. Co-expression of exocrine products in such tumors is related to hormone dependency.

Expression of apocrine differentiation markers in neuroendocrine breast carcinomas of aged women

Neuroendocrine (NE) breast carcinomas are a rare entity in young women; however, their frequency increases in aged patients. The present work demonstrates that NE breast carcinomas in elderly women can also express an apocrine immunophenotype and analyzes the histological and clinical aspects of such differentiation. A selected series of 50 NE tumors (positive for NE markers in >/=50% of the cells) was tested for the immunocytochemical expression of gross cystic disease fluid protein-15 (GCDFP-15). The results demonstrated that about 50% of moderately (G2) and well-differentiated (G1) NE breast carcinomas (mucinous, solid papillary, and solid cohesive histotypes) coexpressed the apocrine marker. In these cases, specific mRNA for GCDFP-15 (PIP) and for chromogranin A (ChA) was demonstrated using in situ hybridization (ISH). Carcinomas of the alveolar subtype (G2) and poorly differentiated carcinomas (G3), including one case of atypical carcinoid, were pure NE carcinomas, devoid of apocrine differentiation. The steroid receptor status of these lesions was evaluated to test a possible involvement of androgen receptors in apocrine differentiation. We demonstrated that the level of AR and the mean age of patients at diagnosis were significantly higher in apocrine than in nonapocrine differentiated tumors. The histological grade and the expression of estrogen receptor (ER) significantly influenced the prognosis of these NE carcinomas, either pure or NE-apocrine differentiated. The most original result of our study is therefore the demonstration of a possible divergent apocrine differentiation of NE breast carcinomas that might be regulated by the activation of androgen receptors in elder patients. In addition, the possibility for using Chs or GCDFP-15 serum values in the follow-up of these patients, as demonstrated in two cases of the present series, can justify the immunophenotyping of the tumors.