George Kanakis

Biochemical markers for gastroenteropancreatic neuroendocrine tumours (GEP-NETs).

Biochemical markers are applied in gastroenteropancreatic neuroendocrine tumours (GEP-NETs) for diagnostic, prognostic or predictive purposes. Chromogranin A is the most important general marker and it is recommended to be measured in every patient with a suspected NET, whereas Neuron Specific Enolase is elevated mainly in poorly differentiated NETs. Pancreatic Polypeptide is used in the diagnosis of pancreatic non-functioning NETs, whereas Chorionic Gonadotrophin has an adjunctive role. In the case of functioning tumours, specific markers should be sought and monitored during follow up. Endogenous hyperinsulinemia is suggested in the presence of non-suppressible insulin and proinsulin levels during hypoglycemia, whereas high fasting or stimulated gastrin levels along with elevated gastric acid output are diagnostic for the Zollinger-Ellison syndrome. Glucagon, vasoactive intestinal polypeptide (VIP) and somatostatin are markers for glucagonoma, VIP-oma and somatostatinoma syndromes respectively. In case of ectopic paraneoplastic syndrome, the relevant hormone serves as a diagnostic and prognostic marker.

Combination treatment with metronomic temozolomide, bevacizumab and long-acting octreotide for malignant neuroendocrine tumours.

Neuroendocrine tumours (NETs) are highly vascularised tumours that express high levels of the vascular endothelial growth factor (VEGF) ligand together with its receptor VEGFR (Modlin et al. 2008). Although advanced NETs may exhibit a 30–40% response rate to combination chemotherapeutic approaches, the response to single-agent chemotherapy is only 10% (Modlin et al. 2008). Bevacizumab (BVZ; Avastin, Roche, Basle, Switzerland), an anti-VEGF humanised monoclonal antibody, has been shown to exert objective tumour responses and improvement in median time to progression (TTP) in advanced carcinoid tumours (Yao et al. 2008). Additionally, a recently published study reported that temozolomide (TMZ), an oral chemotherapy derivative of dacarbazine, at a dose of 200 mg/m on first 5 days of each 28-day cycle may exert a significant effect on NETs (Ekeblad et al. 2007). A previous report that examined a variety of NETs suggested that the combination of BVZ and TMZ can be safely administered and shows promising activity in patients who had failed to prior treatments (Kulke et al. 2006a). Additionally, there is growing interest on regimens that introduce continuous low-dose TMZ administration as protracted low-dose TMZ regimens may deplete O6-methylguanine DNA methyltransferase (MGMT), an important factor in cases of TMZ resistance and/or inhibit endothelial cell proliferation and formation of tumour vasculature via the so-called metronomic effect (Tolcher et al. 2003, Lam et al. 2007). Although the exact mechanism of action of somatostatin analogues is not well understood, a long-standing hypothesis based on preclinical experiments suggests that they exert an antiangiogenic effect (Grozinsky-Glasberg et al. 2008). Given the high degree of endothelial proliferation, high vascular permeability and high expression of proangiogenic growth factors such as VEGF in NETs, angiogenesis inhibition by multiple pathways may be a rational treatment strategy for these tumours. We

Somatostatin and Dopamine Receptor Profile of Gastroenteropancreatic Neuroendocrine Tumors: An Immunohistochemical Study

Somatostatin and its synthetic analogs act through five specific somatostatin receptors (sstr1–5), found on the cell membrane of various tumors, including endocrine ones. Dopamine—a known neurotransmitter—acts through five membranous dopamine receptors (D1R–D5R) which have recently been found to be expressed in endocrine tumors. We evaluated the immunohistochemical expression of the sstrs and D2R in a large series of gastroenteropancreatic neuroendocrine tumors (GEP-NETs). A total of 22 (28.94%) well-differentiated NETs (WDNETs), 6 (7.89%) WDNETs of uncertain biology, 26 (34.21%) well-differentiated neuroendocrine carcinomas, and 22 (28.94%) poorly differentiated neuroendocrine carcinomas were studied. Overall, 76.31% of the tumors were positive for different types of sstrs with variable intensity of the membranous staining whereas 36.95% were positive for D2R alone. The sstr2A was the most frequently expressed, followed by sstr2B, sstr1, and sstr5. Co-expression of sstrs and D2R was seen in 88.23% of positive tumors. The high rates of sstr2A and sstr2B and in a lower extent of sstr5 expression are of great importance for more accurate imaging, staging and targeted therapy of the disease. The co-expression of sstrs and D2R in a significant number of the studied cases offers a potential therapeutic alternative for GEP-NETs.

Expression of Somatostatin Receptors 1-5 and Dopamine Receptor 2 in Lung Carcinoids: Implications for a Therapeutic Role

Objective: The expression of somatostatin receptors (SSTRs) and dopamine receptor 2 (DR2) in neuroendocrine tumors is of clinical importance as somatostatin analogues and dopamine agonists can be used for their localization and/or treatment. The objective of this study is to examine the expression of the five SSTR subtypes and DR2 in lung carcinoids (LCs). Methods: We conducted a retrospective study of 119 LCs from 106 patients [typical carcinoids (TCs): n = 100, and atypical carcinoids (ACs): n = 19]. The expression of all five SSTR subtypes and DR2 was evaluated immunohistochemically and correlated to clinicopathological data. In a subgroup of cases, receptor expression was further analyzed using semiquantitative RT-PCR. Results: SSTR2A was the SSTR subtype most frequently expressed immunohistochemically (72%), followed by SSTR1 (63%), SSTR5 (40%), and SSTR3 (20%), whereas SSTR4 was negative. DR2 was expressed in 74% and co-expressed with SSTR1 in 56%, with SSTR2A in 59%, with SSTR3 in 19%, and with SSTR5 in 37% of the tumors. Receptor expression was not related to the histological subtype, tumor aggressiveness (disease extent/grading) or functionality; however, DR2 was expressed more frequently in ACs than TCs (95 vs. 70%, p = 0.017). In a subset of patients, RT-PCR findings highly suggested that the expression of SSTR2A, SSTR3, DR2, and to a lesser extent that of SSTR1 and SSTR5 is the outcome of increased gene transcription. Conclusions: The high and variable immunohistochemical expression of the majority of SSTRs along with their co-expression with DR2 in LCs provides a rationale for their possible treatment with agents that target these receptors.

Unusual Complication of a Pancreatic Neuroendocrine Tumor Presenting with Malignant Hypercalcemia

CONTEXT Hypersecretion of PTHrP is a relatively common cause of malignancy-related hypercalcemia but has only been described in a few cases of neuroendocrine tumors (NET). OBJECTIVE The aim of this case report is to describe the clinical syndrome, complex therapeutic interventions, and unusual complications caused by persistent PTHrP hypersecretion in a patient with a pancreatic NET. CASE ILLUSTRATION A 58-yr-old male patient presented with nonspecific abdominal pain and was found to have severe hypercalcemia secondary to a well-differentiated NET of the pancreas associated with extensive liver metastases. Elevated ionized calcium levels accompanied by low serum PTH and remarkably elevated PTHrP concentrations were consistent with PTHrP-related hypercalcemia that proved to be resistant to various chemotherapeutic regimens and supportive therapy. Partial control of the humoral syndrome was obtained only after the application of cytoreductive interventions and the introduction of various molecular targeted therapies. Due to persistent PTHrP action, bone disease emerged in the form of brown tumors. DISCUSSION The manifestation of paraneoplastic syndrome due to PTHrP hypersecretion, despite its rareness in NET, should be considered in the differential diagnosis of hypercalcemia in such tumors. Moreover, the appearance of bone lesions in this setting may be in the context of metabolic bone disease and could be misdiagnosed as bone metastases.

Cladribine therapy in adults with advanced Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is a rare disease, particularly in adults, with an incidence of 1 – 2 cases per million [1]. Although LCH is caused by the proliferation and infi ltration of organs by pathological Langerhans cells, the precise underlying pathology of the disease remains unknown [2]. Th e clinical manifestations of the disease vary widely, since any organ can be aff ected, the most common being the bones, lungs, skin and the pituitary gland [3,4]. Th e course of the disease is unpredictable as it can resolve spontaneously or progress to a disseminated form with fatal consequences [5], with patients with lung involvement exhibiting the highest mortality [3]. Although there are no universally accepted guidelines for the treatment of adults, several regimens including corticosteroids, alkylating agents, antimetabolites, vinca alkaloids, combination chemotherapy and radiation have been used [6]. Despite these therapeutic options a signifi cant number of patients will progress, requiring further therapeutic intervention. Cladribine (2-chlorodeoxyadenosine [2-CdA], Leustatin ® ), a synthetic purine nucleoside analog, has been used in children with LCH with promising results, achieving clinically useful remissions with minimal myelosuppresion [7 – 9]. Similar but relatively limited experience with cladri bine has also been reported in adults [10 – 12]. On this basis we treated fi ve adults with progressive LCH, who had undergone previous treatment, with cladribine. All patients received therapy with cladribine between the years 2005 and 2010. Patients were over 18 years of age with relapsed or refractory LCH (irrespective of prior chemotherapy, steroids, radiation therapy). All included patients had adequate renal and hepatic function. A therapeutic scheme with at least four cycles of cladribine was administered at a dose of 0.14 mg/kg/day from days 1 to 5 as a 2 h infusion every 4 weeks. Pneumocystis and viral prophylaxis with cotrimoxazole and valacyclovir was given for the potential risk of immunosuppression. National Cancer Institute Common Toxicity Criteria were used for the evaluation of toxicity, with grades 3 and 4 being considered signifi cant. Five patients (two women) of Greek origin with a mean age of 43 years (range 19 – 67) were treated. Patients ’

Diagnostic accuracy and clinical significance of the fine needle aspiration Ki-67 labelling index in pancreatic endocrine tumours.

Although pancreatic neuroendocrine tumours (PETs) are rare, autopsy series have revealed a high incidence ranging from 0.8 to 10%, reflecting their relative lack of progression and low malignant potential (Kaltsas et al. 2004). Following the application of current sensitive imaging modalities, it is highly probable that the identification of such lesions will increase (Bruzoni et al. 2008). Although biochemical and/or imaging modalities may help differentiate them from evolving adenocarcinoma, histological confirmation remains the definitive diagnostic procedure. Fine needle aspiration and biopsy (FNAB) of pancreatic lesions can be easily performed during endoscopic ultrasonography (EUS), allowing for the preoperative cytological characterisation of such lesions and the estimation of biological behaviour through Ki-67 labelling index (LI) estimation (Kaltsas et al. 2004). To date, only one study has compared the EUS-FNAB cytological Ki-67LI estimation in 18 patients with surgically obtained histological Ki-67LI, demonstrating an overall good agreement, particularly with low Ki-67LI values (Piani et al. 2008). This relative paucity of data prompted us to review 26 patients who had cytological and histological Ki-67LI estimation. All EUS-FNABprocedureswere performed by the same operator and evaluated by the same cytologist. All histological samples were reviewed by one pathologist who also reviewed in a blindmanner the cytological specimens to delineate the level of concordance between cytologist and pathologist. Comparison was based on the WHO 2010 grading system (Bosman et al. 2010) using the k-statistic. The cytological assessment of the Ki-67LI revealed that 15 (58%) of tumours could be classified as G1, nine (34%) as G2 and two (8%) as G3. The histological assessment of the surgical samples classified 11 (42%) tumours as G1, 13 (50%) as G2 and two (8%) as G3 (Table 1). An agreement between the cytological and the histological Ki-67LI expression was found in 7/11 (64%) patients

Reduced bone mineral density in adult patients with Langerhans cell histiocytosis.

This retrospective study evaluated bone mineral density (BMD) and bone turnover in adults with LCH. Twenty‐five adult patients and 25 matched controls were evaluated with BMD measurement and indices of bone metabolism. A BMD value below the expected range for age (Z‐score ≤ − 2.0) was found in 20% of patients; in particular, all postmenopausal women and men over 50‐years had either osteoporosis or osteopenia. Patients with active disease had significantly lower Z‐scores compared to patients with inactive disease and controls. Reduced bone turnover was found in all 14 patients treated with chemotherapy. No fractures due to osteoporosis were identified during 305.15 patient‐years of follow‐up. Pediatr Blood Cancer 2012; 58: 819–822.

Serum osteoprotegerin, RANKL, and Dkk-1 levels in adults with Langerhans cell histiocytosis.

CONTEXT Langerhans cell histiocytosis (LCH) is a rare disease of unknown etiology with a strong evidence of immunological dysfunction secondary to cytokine dysregulation. OBJECTIVE This study aimed to evaluate serum receptor activator of nuclear factor κB ligand (RANKL), osteoprotegerin (OPG), and Dickkopf-1 (Dkk-1) levels in adult patients with LCH at various stages of the disease. DESIGN This was a cross-sectional study in an adult LCH cohort followed for 12.2 ± 2.1 yr. SETTING The study was conducted in an outpatient clinic. SUBJECTS Twenty-five adult patients with a definitive LCH diagnosis and 50 matched controls participated in the study. INTERVENTIONS Early morning, fasting, venous sampling was conducted in all subjects. MAIN OUTCOME MEASURE We compared RANKL, OPG, and Dkk-1 serum levels between patients and controls, as well as their association with disease parameters. RESULTS Serum OPG levels were significantly higher (3.0 ± 0.2 vs. 1.7 ± 0.1 pmol/liter; P < 0.001), whereas RANKL/OPG ratio was significantly lower (0.201 ± 0.041 vs. 0.471 ± 0.072; P = 0.02) in LCH patients compared to controls. Both higher OPG (adjusted odds ratio, 3.431; 95% confidence interval, 1.329-8.924) and lower RANKL (adjusted odds ratio, 0.144; 95% confidence interval, 0.034-0.605) levels were independently associated with LCH in logistic regression analysis, after adjustment for all other parameters. Dkk-1 did not differ among patients and controls. CONCLUSIONS Adults with LCH have high serum OPG levels and low serum RANKL levels. In contrast with other disorders involving the skeleton, serum Dkk-1 levels are similar between LCH patients and controls.

Primary Hyperparathyroidism in Patients with Gastric Carcinoid Tumors Type 1: An Unusual Coexistence

Objective: Although a number of familiar syndromes are associated with primary hyperparathyroidism (PHP), there is no information regarding the prevalence of PHP in other sporadic neuroendocrine diseases. The aim of this study is to investigate the prevalence of PHP in our group of patients with gastric carcinoid (GC) type 1 tumors. Methods: Twenty-six patients with biopsy-proven GC type 1 tumors were retrospectively studied. The diagnosis of PHP was suspected following elevated or high-normal serum calcium levels and elevated or inappropriate normal parathyroid hormone levels. Further tests for the localization of the hyperfunctioning parathyroid glands included neck ultrasound, 99mTc-SESTAMIBI scanning, and cervical or upper mediastinal MR imaging studies. Four control groups were also studied: two age- and sex-matched groups of individuals with (n = 49) and without (n = 34) thyroid autoimmunity and normal endoscopy of the stomach, a third group with nongastric neuroendocrine tumors (n = 68), and a fourth group with atrophic gastritis and hypergastrinemia, without gastric endocrine tumors (n = 30). Results: PHP was diagnosed in 4 (15.38%) patients with GC type 1 tumors compared to none of the 4 control groups. Three of the 4 patients with PHP were operated and proved to have a parathyroid adenoma. No statistically significant differences were observed between patients with or without PHP in mean gastrin and chromogranin A levels, number of lesions, ki-67 labeling index expression, and maximum GC type 1 tumor diameter. Conclusion: PHP seems to be relatively common, approximately 15% in the present cohort, in patients with GC type 1 tumors. PHP should be actively looked for in such patients and treated accordingly.