Quantifying the Effects of Renal Impairment on Plasma Concentrations of the Neuroendocrine Neoplasia Biomarkers Chromogranin A, Chromogranin B, and Cocaine- and Amphetamine-Regulated Transcript

A Laboratory Medicine Perspective on the Investigation of Phaeochromocytoma and Paraganglioma

Phaeochromocytomas (PC) and sympathetic paragangliomas (PGL) are potentially malignant tumours arising from the adrenal medulla (PC) or elsewhere in the sympathetic nervous system (PGL). These tumours usually secrete catecholamines and are associated with significant morbidity and mortality, so accurate and timely diagnosis is essential. The initial diagnosis of phaeochromocytoma/paraganglioma (PPGL) is often dependent on biochemical testing. There is a range of pre-analytical, analytical and post-analytical factors influencing the analytical and diagnostic performance of biochemical tests for PPGL. Pre-analytical factors include patient preparation, sample handling and choice of test. Analytical factors include choice of methodology and the potential for analytical interference from medications and other compounds. Important factors in the post-analytical phase include provision of appropriate reference ranges, an understanding of the potential effects of various medications on metanephrine concentrations in urine and plasma and a consideration of PPGL prevalence in the patient population being tested. This article reviews these pre-analytical, analytical and post-analytical factors that must be understood in order to provide effective laboratory services for biochemical testing in the diagnosis of PPGL.

Stage II of Chronic Kidney Disease-A Tipping Point in Disease Progression?

Chronic kidney disease (CKD) is the progressive loss of renal function. Although advances have been made in understanding the progression of CKD, key molecular events in complex pathophysiological mechanisms that mark each stage of renal failure remain largely unknown. Changes in plasma protein profiles in different disease stages are important for identification of early diagnostic markers and potential therapeutic targets. The goal of this study was to determine the molecular profile of each CKD stage (from 1 to 5), aiming to specifically point out markedly expressed or downregulated proteins. We performed a cross-sectional shotgun-proteomic study of pooled plasma across CKD stages and compared them to healthy controls. After sample pooling and heparin-column purification we analysed proteomes from healthy to CKD stage 1 through 5 participants' plasma by liquid-chromatography/mass-spectrometry. We identified 453 proteins across all study groups. Our results indicate that key events, which may later affect the course of disease progression and the overall pathophysiological background, are most pronounced in CKD stage 2, with an emphasis on inflammation, lipoprotein metabolism, angiogenesis and tissue regeneration. We hypothesize that CKD stage 2 is the tipping point in disease progression and a suitable point in disease course for the development of therapeutic solutions.

Addition of 3-methoxytyramine or chromogranin A to plasma free metanephrines as the initial test for pheochromocytoma and paraganglioma: Which is the best diagnostic strategy

OBJECTIVE

Measurements of plasma free metanephrines (MNs), including MN and normetanephrine, provide high sensitivity and specificity for the diagnosis of pheochromocytoma and paraganglioma (PPGL). 3-Methoxytyramine (3-MT) and chromogranin A (CgA) may allow the detection of dopamine-producing or biochemically silent PPGL. The aim of this study was to evaluate whether measurements of plasma 3-MT or CgA as a supplement of plasma MNs offer a better diagnostic strategy for initial testing of PPGL.

PATIENTS AND DESIGN

We enroled 125 patients who underwent surgery from 2015 to 2016 for our study and identified 33 patients with PPGL and 92 patients with non-PPGL masses.

MEASUREMENT

The levels of plasma free MNs and 3-MT were measured for all 125 patients using liquid chromatography-tandem mass spectrometry. Plasma CgA concentrations were determined using a radioimmunoassay. To evaluate the diagnostic performance of plasma free MNs, 3-MT and CgA, sensitivity and specificity were determined, and receiver operating characteristic curves were constructed.

RESULTS

We found that combining 3-MT and MNs increased the diagnostic sensitivity from 93.9% (95% confidence interval [CI]: 78.4%-98.9%) to 97.0% (95% CI: 82.5%-99.8%). In contrast, addition of plasma CgA test reduced the diagnostic specificity significantly from 91.3% (95% CI: 83.1%-95.9%) to 75.0% (95% CI: 64.7%-83.2%).

CONCLUSION

Here, we demonstrated that 3-MT represents a valuable supplementary test to plasma MNs, which can further enhance the sensitivity of the assay, while plasma CgA added no additional diagnostic value to MNs due to the lowered diagnostic specificity.

Serum chromogranin A correlated with albuminuria in diabetic patients and is associated with early diabetic nephropathy

BACKGROUND

The kidney is the main site for the removal of chromogranin A (CgA). Previous studies have found that patients with renal impairment displayed elevated concentrations of CgA in plasma and that CgA concentrations reflect a deterioration of renal function. In this study, we aimed to estimate serum CgA levels and to evaluate the role of serum CgA in the early diagnosis of diabetic nephropathy (DN).

METHODS

A total of 219 patients with type 2 diabetes mellitus (T2DM) were included in this cross-sectional study. These patients were classified into normoalbuminuria (n = 121), microalbuminuria (n = 73), or macroalbuminuria (n = 25) groups based on their urine albumin to creatinine ratios (UACRs). The degree of DN is reflected by UACR. A control group consisted of 45 healthy subjects. The serum CgA levels were measured by ELISA, and other key parameters were assayed.

RESULTS

Serum CgA levels were higher in patients with T2DM than in control subjects, and a statistically significant difference among the studied subgroups regarding CgA was found (P < 0.05). The levels of serum CgA increased gradually with the degree of DN (P < 0.001). Serum CgA levels showed a moderate-intensity positive correlation with UACRs (P < 0.001). A cutoff level of 3.46 ng/ml CgA showed 69.86% sensitivity and 66.12% specificity to detect DN in the early stage.

CONCLUSION

The levels of serum CgA increased gradually with the degree of DN and can be used as a biomarker in the early detection of DN.

A UK national audit of the laboratory investigation of phaeochromocytoma and paraganglioma

BACKGROUND

Phaeochromocytomas and paragangliomas (PPGL) are catecholamine secreting tumours associated with significant morbidity and mortality. Timely diagnosis and management are essential. A range of laboratory tests can be utilised in the investigation of PPGL. There is scope for significant variation in practice between centres. We aimed to investigate how the laboratory investigation of PPGL is performed in laboratories across the United Kingdom.

METHODS

A questionnaire consisting of 21 questions was circulated to Clinical Biochemistry laboratories in the United Kingdom via the Association for Clinical Biochemistry and Laboratory Medicine office. The survey was designed to allow audit against Endocrine Society Guidelines on the Investigation and Management of PPGL and to obtain information on other important aspects not included in these guidelines.

RESULTS

Responses were received from 58 laboratories and the data were compiled. The majority of laboratories use either urine or plasma metanephrines in first-line testing for PPGL, although a number of different combinations of biochemistry tests are utilised in different centres. All laboratories measuring metanephrines or catecholamines in-house use LC or LC-MS/MS methods. There are some marked differences between laboratories in urine metanephrines reference ranges used and sample requirements.

CONCLUSIONS

There is evidence of good practice in UK laboratories (as assessed against Endocrine Society Guidelines) such as widespread use of urine/plasma metanephrines and appropriate analytical methodologies used. However, there is also evidence of variations in practice in some areas that should be addressed.

Plasma Catestatin Levels and Advanced Glycation End Products in Patients on Hemodialysis

Catestatin (CST) is a pleiotropic peptide involved in cardiovascular protection with its antihypertensive and angiogenic effects. Considering that patients with end-stage renal disease (ESRD) who are undergoing hemodialysis (HD) are associated with higher cardiovascular risk, the aim of this study was to investigate plasma CST levels in HD patients, compare them to healthy controls and evaluate possible CST associations with advanced glycation end products (AGEs) and laboratory, anthropometric and clinical parameters. The study included 91 patients on HD and 70 healthy controls. Plasma CST levels were determined by an enzyme-linked immunosorbent assay in a commercially available diagnostic kit, while AGEs were determined using skin autofluorescence. Plasma CST levels were significantly higher in the HD group compared to the controls (32.85 ± 20.18 vs. 5.39 ± 1.24 ng/mL, p < 0.001) and there was a significant positive correlation between CST and AGEs (r = 0.492, p < 0.001). Furthermore, there was a significant positive correlation between plasma CST levels with both the Dialysis Malnutrition Score (r = 0.295, p = 0.004) and Malnutrition-Inflammation Score (r = 0.290, p = 0.005). These results suggest that CST could be playing a role in the complex pathophysiology of ESRD/HD and that it could affect the higher cardiovascular risk of patients on HD.

Serum Elastase 1 Level as a Risk Factor for Postoperative Recurrence in Patients with Well-Differentiated Pancreatic Neuroendocrine Neoplasms

PURPOSE

This study was designed to assess the potential role of the preoperative serum level of elastase 1 as a risk factor for recurrence in patients with resectable well-differentiated pancreatic neuroendocrine neoplasms (PanNETs).

METHODS

Preoperative serum elastase 1 levels were measured in 53 patients with PanNETs who underwent complete tumor resection in two tertiary referral centers between January 2004 and June 2017. The preoperative elastase 1 levels were correlated with clinicopathological characteristics, including tumor recurrence and recurrence-free survival.

RESULTS

The median elastase 1 level was 96 ng/dL (range: 21-990 ng/dL). Preoperative serum elastase 1 levels were significantly higher in those with tumors ≥ 20 mm in diameter (vs. < 20 mm, P = 0.018), WHO grade 2 (vs. grade 1, P = 0.035), and microscopic venous invasion (vs. without venous invasion, P = 0.039). The median preoperative serum level of elastase 1 was higher in patients with recurrence than in those without recurrence (251 vs. 80 ng/dL, P = 0.004). Receiver operating characteristic analysis of elastase 1 levels showed that a cutoff level of 250 ng/dL was associated with postoperative recurrence, with 63% sensitivity, 100% specificity, and 94% overall accuracy. Patients with higher elastase 1 levels showed significantly worse recurrence-free survival than that of those with lower levels (2-year recurrence-free survival rate: 25% and 92%, respectively, P < 0.001).

CONCLUSIONS

Our data provide the first evidence that high preoperative elastase 1 levels may be a risk factor for postoperative recurrence in patients with resectable PanNETs.

A score derived from routine biochemical parameters increases the diagnostic accuracy of chromogranin A in detecting patients with neuroendocrine neoplasms

BACKGROUND

Chromogranin A (CgA) is a valuable biomarker for detection and follow-up of patients with neuroendocrine neoplasms (NENs). However, various comorbidities may influence serum CgA, which decreases its diagnostic accuracy. We aimed to investigate which laboratory parameters are independently associated with increased CgA in real-life setting and to develop a scoring system, which could improve the diagnostic accuracy of CgA in detecting patients with NENs.

METHODS

This retrospective study included 55 treatment naïve patients with NENs and160 patients with various comorbidities but without NEN (nonNENs). Scoring system (CgA-score) was developed based on z-scores obtained from receiver operating curve analysis for each parameter that was associated with elevated serum CgA in nonNENs.

RESULTS

CgA correlated positively with serum BUN, creatinine, α2-globulin, red-cell distribution width, erythrocyte sedimentation rate, plasma glucose and correlated inversely with hemoglobin, thrombocytes and serum albumin. Serum CgA was also associated with the presence of chronic renal failure, arterial hypertension and diabetes and the use of PPI. In the entire study population, CgA showed an area under the curve of 0.656. Aforementioned parameters were used to develop a CgA-score. In a cohort of patients with CgA-score <12.0 (N = 87), serum CgA >156.5 ng/ml had 77.8% sensitivity and 91.5% specificity for detecting NENs (AUC 0.841, 95% CI 0.713-0.969, P < 0.001). Serum CgA had no diagnostic value in detecting NENs in patients with CgA-score >12.0 (AUC 0.554, 95% CI 0.405-0.702, P = 0.430).

CONCLUSIONS

CgA-score encompasses a wide range of comorbidities and represents a promising tool that could improve diagnostic performance of CgA in everyday clinical practice.

Follow-Up for Resected Gastroenteropancreatic Neuroendocrine Tumours: A Practice Survey of the Commonwealth Neuroendocrine Tumour Collaboration (CommNETS) and the North American Neuroendocrine Tumor Society (NANETS)

OBJECTIVES

There is no consensus regarding optimal follow-up in resected gastroenteropancreatic neuroendocrine tumours (NETs). We aimed to perform a practice survey to ascertain follow-up patterns by health care practitioners and highlight areas of variation that may benefit from further quantitative research.

METHODS

A Web-based survey targeted at NET health care providers in Australia, New Zealand, Canada, and the USA was developed by a steering committee of medical oncologists and a research methodologist. Thirty-seven questions elicited information regarding adherence to guidelines, the influence of risk factors on follow-up, and the frequency and choice of modality in follow-up.

RESULTS

There were 163 respondents: 59 from Australia, 25 from New Zealand, 46 from Canada, and 33 from the USA (50% medical oncology, 23% surgery, 13% nuclear medicine, and 15% other). Thirty-eight percent of the respondents were "very familiar" with the NCCN NET guidelines, 33% with the ENETS guidelines, and 17% with the ESMO guidelines; however, only 15, 27, and 10%, respectively, found them "very useful"; 63% reported not using guidelines at their institution. The commonest investigations used were CT scans (66%) and chromogranin A (86%). The US respondents were more likely to follow patients up past 5 years, and the Australian respondents utilized more functional and less cross-sectional imaging. When poor prognostic factors were introduced, the respondents recommended more visits and tests.

CONCLUSIONS

This large international survey highlights variation in current follow-up practices not well addressed by the current guidelines. More quantitative research is required to inform the development of evidence-based guidelines tailored to the pattern of recurrence in NETs.

Regulation of circulating chromogranin B levels in heart failure

BACKGROUND

Chromogranin B (CGB) regulates B-type natriuretic peptide (BNP) production. Circulating CGB levels are elevated in heart failure (HF) animal models and HF patients, but also increase in healthy individuals in response to physical activity. Therefore, CGB seems to integrate information from myocardial stress and systemic neuro-endocrine activation. Substantial gaps remain in our understanding of CGB regulation in HF.

METHODS AND RESULTS

We conducted a retrospective registry study including 372 patients. CGB and N-terminal pro-BNP (NT-proBNP) plasma levels were assessed in acute HF and chronic valvular HF patients and controls. CGB levels were significantly increased in acute HF and chronic valvular HF, but significantly higher in the latter. Patients in chronic valvular HF with severe mitral regurgitation (cHF-MR) showed significantly higher CGB levels than patients in chronic valvular HF with severe aortic stenosis. CGB levels progressively increased with worsening NYHA functional status and were moderately correlated to NT-proBNP, but independent of left ventricular (LV) ejection fraction (LVEF), LV mass, age and body weight. Finally, cHF-MR patients showed significant reductions of CGB levels after interventional mitral valve repair.

CONCLUSION

CGB is a promising emerging biomarker in HF patients with unique potential to integrate information from myocardial stress and neuro-endocrine activation.

Reference limits for chromogranin A, CYFRA 21-1, CA 125, CA 19-9 and carcinoembryonic antigen in patients with chronic kidney disease

BACKGROUND

Patients with chronic kidney disease (CKD) may have increased plasma concentrations of some tumor markers even when no cancer is present. Previous studies have indicated that plasma concentrations of chromogranin A (CGA), cytokeratin 19 fragments (CYFRA 21-1), cancer antigen 125 (CA 125), cancer antigen 19-9 (CA 19-9) and carcinoembryonic antigen (CEA) are higher in patients with CKD but without cancer, than in healthy individuals, and this can make interpretation of results more complicated. The aim of this study was to establish reference limits for these markers in patients with CKD not receiving dialysis and with no clinical evidence of cancer.

METHODS

We measured plasma concentrations in samples from 131 patients with CKD due to various etiologies and studied the association of tumor marker concentrations with estimated glomerular filtration rate (GFR) and other patient characteristics.

RESULTS

Estimated reference limits for plasma CA 125, CA 19-9 and CEA were approximately the same as for healthy populations. Serum concentrations of CGA and CYFRA 21-1 correlated strongly with estimated GFR, and GFR-dependent reference limits were estimated.

CONCLUSIONS

GFR-dependent reference limits for CGA and CYFRA 21-1 are reported in order to support interpretation of these markers in patients with CKD.

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.

Advances in the diagnosis and treatment of pancreatic neuroendocrine neoplasms in Japan

Several new developments have occurred in the field of pancreatic neuroendocrine neoplasm (PNEN) recently in Japan. First, the utility of chromogranin A (CgA), useful for the diagnosis and monitoring of the treatment response of neuroendocrine neoplasm (NEN), has been demonstrated in Japan. For PNEN diagnosis and treatment, grading and correct histological diagnosis according to the WHO 2010 classification is important. Regarding the histological diagnosis, the advent of endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA) has enabled correct pathological diagnosis and suitable treatment for the affected tissue. Furthermore, EUS-FNA has also facilitates the assessment of the presence or absence of gene mutations. In addition, patients who have a well-differentiated neuroendocrine tumor (NET) showing a Ki-67 index of higher than 20 % according to the WHO 2010 classification, have also been identified, and their responses to treatment were found to be different from those of patients with poorly differentiated neuroendocrine carcinoma (NEC). Therefore, the concept of NET G3 was proposed. Additionally, somatostatin receptor type 2 is expressed in several cases of NET, and somatostatin receptor scintigraphy (¹¹¹In-octreoscan) has also been approved in Japan. This advancement will undoubtedly contribute to the localization diagnosis, the identification of remote metastasis, and assessments of the treatment responses of PNEN. Finally, regarding the treatment strategy for PNEN, the management of liver metastasis is important. The advent of novel molecular-targeted agents has dramatically improved the prognosis of advanced PNEN. Multimodality therapy that accounts for the tumor stage, degree of tumor differentiation, tumor volume, and speed of tumor growth is required.

Chromogranin A as biomarker in diabetes

Chromogranin A (CgA) is an established plasma marker of neuroendocrine tumors and has been suggested to also have a role as biomarker in other diseases. Whether CgA has any role as biomarker in diabetes is, however, unresolved, but its widespread distribution in the secretory granules in endocrine tissues including β cells and α cells in pancreas, and the metabolic effects of its peptide fragments suggest that CgA may play a pathophysiological role in diabetes, and thus also be a potential diabetes biomarker. In this review, we summarize the available information on CgA and some of its functional post-translational cleavage products in diabetes, followed by a discussion of its potential as a plasma marker in diabetes and the methodological concerns involved.

Plasma free metanephrine and normetanephrine levels are increased in patients with chronic kidney disease

OBJECTIVE

Patients with impaired renal function, particularly those on dialysis, frequently exhibit high blood pressure and hemodynamic instability, which often lead to pheochromocytoma assessment. Our objective was to assess plasma free metanephrine (MN) and normetanephrine (NMN) in chronic kidney disease patients (CKD) with or without dialysis.

METHODS

In this prospective observational study we performed enzyme-linked immunosorbent assays (ELISAs) to evaluate plasma free MN and NMN in 48 CKD patients (15 with stage 3-5 CKD without dialysis, 26 on hemodialysis [HD], and 7 continuous ambulatory peritoneal dialysis [CAPD]), 30 patients with histologically proven pheochromocytoma, and 43 hypertensive patients. Adrenal masses were ruled out by abdominal computed tomography (CT) scans in all CKD and control hypertensive patients.

RESULTS

All 3 CKD groups (HD, CAPD, and CKD without dialysis) had significantly higher plasma free MN and NMN levels than the control hypertensive group (P<.0055). HD and CAPD patients had significantly lower plasma free NMN (P<.0055), but free MN levels were not significantly different than those observed in pheochromocytoma patients. In patients with HD, CAPD, and CKD without dialysis, plasma free MN and NMN were higher than manufacturer's upper limits of normal in 57.7% and 28.5%, 13.3% and 61.5%, and 85.7% and 26.6%, respectively. Regression models showed that the number of dialysis years was significantly correlated with plasma free MN (r = 0.615, P<.001) but not free NMN.

CONCLUSION

Plasma free MN and NMN levels are frequently elevated in CKD patients, particularly in those on dialysis. Plasma free MN levels significantly overlap with the range in pheochromocytoma patients and correlate with the number of years on dialysis.

Routine measurement of plasma chromogranin B has limited clinical utility in the management of patients with neuroendocrine tumours

OBJECTIVE

Chromogranin A (CgA) and B (CgB) are markers for monitoring disease status in patients with gastroenteropancreatic neuroendocrine tumours (NETs). These are specialized diagnostic tests often necessitating referral of specimens to a supraregional assay service (SAS) laboratory for analysis. The aim of this audit was to assess whether measurement of either plasma CgA or CgB alone provides sufficient clinical information in comparison with the current practice of measuring both markers together.

DESIGN

A retrospective analysis was undertaken for all chromogranin tests requested for patients with a known NET diagnosis. Results were categorized based on whether plasma concentrations were elevated for one or both CgA and CgB.

RESULTS

A total of 325 sequential patients with a NET diagnosis had plasma chromogranin levels measured during the period of review. Baseline CgA was elevated in 60·9% of patients. Isolated elevations in CgA (with normal CgB) were found in 44·9% of patients, whilst combined elevations in both CgA and CgB were found in 16% of patients. Combined CgA and CgB concentrations within the normal range were observed for 38·5% of patients. Only two patients (0·6%) had an isolated elevation in CgB at baseline. Both patients had a diagnosis of pancreatic NET and were radiologically stable. Plasma CgA and CgB corresponded with disease stage (localized vs metastatic). CgB in addition to CgA did not provide any significant improvement in diagnostic performance for identification of metastatic disease compared to CgA alone.

CONCLUSIONS

Based on this NET population and specific assay performance characteristics, CgA alone provides sufficient information for the management of NET patients; the routine estimation of CgB in all patients is not informative in clinical practice.

Serum and plasma 5-hydroxyindoleacetic acid as an alternative to 24-h urine 5-hydroxyindoleacetic acid measurement

BACKGROUND

Neuroendocrine tumours are slow growing tumours known to secrete a variety of vasoactive peptides which give rise to symptoms of the carcinoid syndrome. The diagnosis and monitoring of patients with neuroendocrine tumours is undertaken in many centres using 24 h urinary measurement of 5-hydroxyindoleacetic acid. However, 5-hydroxyindoleacetic acid can also be quantified in plasma and serum.

METHODS

We measured 5-hydroxyindoleacetic acid concentration in 134 paired EDTA plasma and urine samples from 108 patients with known neuroendocrine tumours and 26 healthy volunteers. We also compared 5-hydroxyindoleacetic acid concentrations in paired serum and plasma samples (n = 63), then analysed paired urine and serum samples (n = 97). Furthermore, we examined the impact of renal impairment on serum 5-hydroxyindoleacetic acid by analysing 5-hydroxyindoleacetic acid in patients without neuroendocrine tumours in different stages of chronic kidney disease, as indicated by the estimated glomerular filtration rate.

RESULTS

Plasma and urine 5-hydroxyindoleacetic acid had very similar diagnostic sensitivities and specificities, with areas under the curve on ROC analysis of 0.917 and 0.920, respectively. Serum and plasma 5-hydroxyindoleacetic acid values showed good correlation but serum results demonstrated a positive bias, indicating the necessity for different serum and plasma reference intervals. There was an inverse correlation between estimated glomerular filtration rate and serum 5-hydroxyindoleacetic acid concentration, with 5-hydroxyindoleacetic acid increasing once the estimated glomerular filtration rate falls below 60 mL/min/1.73 m(2).

CONCLUSION

The measurement of both serum and plasma 5-hydroxyindoleacetic acid can be used for the diagnosis and monitoring of patients with neuroendocrine tumours. Provided renal function is taken into consideration, either of these tests should be incorporated into standard practice as an alternative assay to urinary 5-hydroxyindoleacetic acid.

Somatostatin receptors over-expression in castration resistant prostate cancer detected by PET/CT: preliminary report of in six patients

Prostate cancer (PC) is usually characterized by an excellent prognosis, largely due to little biological aggressiveness and the power of hormonal deprivation therapy. In spite of these favorable characteristics, however, a significant quota of patients does not respond to androgen deprivation therapy (ADT) and develop a progressive disease. Castration-resistant prostate cancer (CRPC) is defined by disease progression in spite of ADT. This progression may show any combination of a rise in serum prostate-specific antigen (PSA), clinical and radiological progression of pre-existing disease, and appearance of new metastases. This event is a striking change in the clinical scenario, since the power of treatment for CRPC patients with distant metastases is very limited. Somatostatin is a hormone produced by neuroendocrine cells. Its distant effects are mediated by the binding to five specific receptors, which are the most striking parameter for neuroendocrine. Various synthetic somatostatin agonists able to bind to the receptors have been synthesized during the past two decades for diagnostic and therapeutic purposes. Octreotide, the most popular of these, is widely used to treat patients affected by neuroendocrine tumors. A number of researches carried out in the past evaluated the possible neuroendocrine differentiation (NED) of PC cells in the castration resistant phase. If proved, the presence of a specific class of receptor on cell's surfaces should give a potentially biological target to be used for therapy. However, these studies led to contradictory results. Aim of our phase III diagnostic trial was to study "in vivo" the over-expression of somatostatin receptors (SSTRs) in CRPC patients by PET/CT after the administration of the somatostatin analog [(68)Ga-DOTANOC,1-Nal(3)]-octreotide labeled with (68)Ga. Every area of increased uptake corresponding to a metastasis detected with other methods was considered as SSTRs expressing. False positivity to SSTRs expression was considered those localizations with a suspicious uptake not confirmed by other radiologic procedures. On the other hand, metastatic lesions lacking the radiopharmaceutical's uptake were considered not SSTRs expressing metastases. The preliminary results in 6 of the 67 patients scheduled by our phase III trial showed metastases with a variable SSTRs expression in 2 patients.

A maintenance hemodialysis diabetic patient with unexplained pulmonary and gastrointestinal involvement

A 50-year-old man with diabetes mellitus with diabetic retinopathy, peripheral neuropathy, hypertension, and end-stage renal disease on maintenance hemodialysis, presented with persistent cough and hiccups, continued to be unwell with weight loss, poor appetite, and recurrent respiratory symptoms such as wheezing and cough. Whole body positron emission tomography-computed tomography scan showed metabolically active lesions in liver, stomach/lesser sac, pancreas, and left sixth rib. As he had repeated bilateral transudative pleural effusion, left mini thoracotomy with pleural biopsy showed no evidence of granuloma or malignancy. Upper gastroscopy showed tiny gastric polyp; biopsy revealed benign lesion. Left posterior rib biopsy from the lesion and iliac crest biopsy showed no evidence of malignancy or granuloma. Further evaluation showed plasma chromogranin A -5737 μg/L (<100 μg/L) with a repeat value of 6950 μg/L (<100 μg/L). He was initiated on oral sunitinib 25 mg once a day and injection octreotide 20 mg subcutaneously once a month. The plasma chromogranin A level and his symptoms, however, showed an initial improvement, but gradually worsened after 4 months despite being on treatment. After 6 months, the patient developed a gangrenous lesion of his glans penis with necrosis. Due to severe pain on conservative measures, penectomy with perineal urethrostomy was performed. Biopsy of the lesion showed blood vessels with intimal calcifications and thrombosis suggesting penile necrosis.

Lanthanum-Induced Gastrointestinal Histiocytosis

A patient with end-stage renal disease (ESRD) on hemodialysis presented with fever, anorexia, and nausea shortly after starting oral lanthanum carbonate for phosphate control. Gastric and duodenal biopsies demonstrated diffuse histiocytosis with intracellular aggregates of basophilic foreign material. Transmission electron microscopy, an underutilized diagnostic test, revealed the nature of the aggregates as heavy metal particles, consistent with lanthanum. Symptoms and histiocytosis improved after discontinuation of lanthanum. Lanthanum may be an underdiagnosed cause of gastrointestinal histiocytosis.

Circulating tumor markers in patients with neuroendocrine tumors – a clinical perspective

Abstract: 

Neuroendocrine tumors (NETs) are uncommon malignancies with a very diverse presentation and prognosis. Patients with NETs frequently have circulating tumor biomarkers that may aid in the diagnosis and help with prognostication. The most commonly used and best studied marker is chromogranin A, which appears to reflect the tumor burden and is useful at the time of diagnosis, and to monitor for recurrence after resection as well as to assess response to systemic therapy. Despite being the best studied marker, chromogranin A has significant limitations. Multiple other biomarkers are in use, but most have not been studied well and need further validation before being recommended for clinical practice. We review both established and novel circulating biomarkers, and highlight some of the limitations of tumor marker use in patients with NETs.

Mast cell activation syndrome as a significant comorbidity in sickle cell disease

Supplemental Digital Content is Available in the Text.

Some sickle cell anemia (SCA) patients suffer significantly worse phenotypes than others. Causes of such disparities are incompletely understood. Comorbid chronic inflammation likely is a factor. Recently, mast cell (MC) activation (creating an inflammatory state) was found to be a significant factor in sickle pathobiology and pain in a murine SCA model. Also, a new realm of relatively noncytoproliferative MC disease termed MC activation syndrome (MCAS) has been identified recently. MCAS has not previously been described in SCA. Some SCA patients experience pain patterns and other morbidities more congruent with MCAS than traditional SCA pathobiology (eg, vasoocclusion). Presented here are 32 poor-phenotype SCA patients who met MCAS diagnostic criteria; all improved with MCAS-targeted therapy. As hydroxyurea benefits some MCAS patients (particularly SCA-like pain), its benefit in SCA may be partly attributable to treatment of unrecognized MCAS. Further study will better characterize MCAS in SCA and identify optimal therapy.

Serum chromogranin A is a useful marker for Japanese patients with pancreatic neuroendocrine tumors

Although chromogranin A (CGA) is a useful marker for pancreatic neuroendocrine tumors (pNET) in the West, its usefulness in Japanese populations is unclear. To assess this, we evaluated the serum CGA levels in 189 patients with various pancreatic diseases, including proven pNET (n = 69), pancreatic cancer (PC) (n = 50), chronic pancreatitis (CP) (n = 50) and autoimmune pancreatitis (AIP) (n = 20), and 112 normal controls (controls) using an ELISA kit. The mean CGA level of patients with pNET was significantly higher than any of the other groups (407.8 ± 984.6 ng/mL [pNET] vs 91.8 ± 101.8 ng/mL [PC], 93.6 ± 57.5 ng/mL [CP], 69.9 ± 52.4 ng/mL [AIP] and 62.5 ± 48.3 ng/mL [controls]). Limiting the analysis to patients not using proton pump inhibitors (PPI), the CGA level of patients with PC or CP was not significantly different compared with the controls. Discriminant analysis revealed that the best cut-off value of CGA to distinguish patients with pNET from the controls was 78.7 ng/mL, with a sensitivity and specificity of 53.6% and 78.6%, respectively. In patients with pNET, significant factors associating with elevated CGA levels were tumor classification, tumor size, and the presence of liver metastases in univariate analysis as well as PPI use and the presence of liver metastases in multivariate analysis. We show that CGA is a useful marker for diagnosing pNET in Japanese populations and for distinguishing patients with pNET from patients with other pancreatic diseases. The increased use of CGA in Japan will likely be a helpful tool in managing these patients, as found in the West.

The biochemical utility of chromogranin A, chromogranin B and cocaine- and amphetamine-regulated transcript for neuroendocrine neoplasia

Neuroendocrine neoplasia (NEN) is a heterogeneous group of tumours and often represents a therapeutic challenge to clinicians. The peptides chromogranin A (CgA), chromogranin B (CgB) and cocaine- and amphetamine-regulated transcript (CART) are widely distributed throughout the neuroendocrine system. CgA and CgB have been used as general NEN biomarkers for many years, while CART has only recently been identified. Of these biomarkers, CgA is the most commonly used. However, circulating CgA concentrations exhibit considerable intra-individual biological variation, are altered by proton pump inhibitors (PPIs) and somatostatin analogues and are elevated in non-NEN malignancies. Therefore, interpretation of CgA results must be in the context of these confounding factors. The effects of treatment and non-NEN conditions on circulating CgB and CART concentrations are less well understood. CgB is less affected by impaired renal function and PPIs than CgA; while, circulating CART concentrations lack a diurnal variation in humans and are more reliable markers of pancreatic NEN malignancy than CgA. The utility of circulating CgA measurements in NEN prognosis, surveillance and disease recurrence has been widely investigated. However, the utility of CgB and CART in NEN management is yet to be elucidated. Further studies are needed to establish whether CgB and CART are useful alternatives to CgA.

Peptide receptor radionuclide therapy with (90)Y-DOTATATE/(90)Y-DOTATOC in patients with progressive metastatic neuroendocrine tumours: assessment of response, survival and toxicity

Background:

Peptide receptor radionuclide therapy (PRRT) is an established treatment for patients with metastatic neuroendocrine tumours (NETs), although which factors are associated with an improved overall survival (OS) remains unclear. The primary aim of this study is to determine to what extent a radiological response to ⁹⁰Y-DOTATOC/⁹⁰Y-DOTATATE PRRT is associated with an improved OS. The association of biochemical and clinical response to OS were assessed as secondary outcome measures.

Methods:

A retrospective analysis was conducted on 57 patients: radiological response was classified using RECIST criteria, biochemical response was classified using WHO criteria and clinical response was assessed subjectively. Responses were recorded as positive response (PR), stable disease (SD) or progressive disease (PD), and survival analysed.

Results:

Radiological response was achieved in 71.5% (24.5% PR, 47% SD) and was associated with a greater OS (51 and 56 months, respectively), compared with PD (18 months). A biochemical or clinical response post PRRT were not associated with a statistically significant improvement in OS. However, when combined with radiological response a survival benefit was observed according to the number of outcomes (radiological, biochemical, clinical), in which a response was observed. Mild haematological toxicity was common, renal toxicity was rare.

Conclusion:

In patients with progressive metastatic NETs receiving ⁹⁰Y-DOTATOC/⁹⁰Y-DOTATATE PRRT, a radiological response with either a PR or a SD post therapy confers a significant OS benefit.