Resistance to osimertinib in advanced EGFR-mutated NSCLC: a prospective study of molecular genotyping on tissue and liquid biopsies.

BACKGROUND: Resistance to osimertinib in advanced EGFR-mutated non-small cell lung cancer (NSCLC) constitutes a significant challenge for clinicians either in terms of molecular diagnosis and subsequent therapeutic implications. METHODS: This is a prospective single-centre study with the primary objective of characterising resistance mechanisms to osimertinib in advanced EGFR-mutated NSCLC patients treated both in first- and in second-line. Next-Generation Sequencing analysis was conducted on paired tissue biopsies and plasma samples. A concordance analysis between tissue and plasma was performed. RESULTS: Sixty-five advanced EGFR-mutated NSCLC patients treated with osimertinib in first- (n = 56) or in second-line (n = 9) were included. We managed to perform tissue and liquid biopsies in 65.5% and 89.7% of patients who experienced osimertinib progression, respectively. Acquired resistance mechanisms were identified in 80% of 25 patients with post-progression samples, with MET amplification (n = 8), EGFR C797S (n = 3), and SCLC transformation (n = 2) the most frequently identified. The mean concordance rates between tissue and plasma for the EGFR activating mutation and for the molecular resistance mechanisms were 87.5% and 22.7%, respectively. CONCLUSIONS: Resistance to osimertinib demonstrated to be highly heterogeneous, with MET amplification the main mechanism. Plasma genotyping is a relevant complementary tool which might integrate tissue analysis for the study of resistance mechanisms.

Primary resistance to osimertinib due to SCLC transformation: Issue of T790M determination on liquid re-biopsy.

OBJECTIVES: EGFR T790M mutation is the most common mechanism of resistance to first-/second-generation EGFR tyrosine kinase inhibitors (TKIs) in non-small cell lung cancer (NSCLC) and could be overcome by third-generation EGFR-TKIs, such as osimertinib. Liquid biopsy, a non-invasive technique used to test the presence of the resistant mutation, may help avoiding tissue re-biopsy. However, analysing only circulating-free DNA, information about other less frequent and coexisting resistance mechanisms may remain unrevealed. MATERIALS AND METHODS: All patients reported in this series participated in the ASTRIS trial, a real world treatment study testing the efficacy of osimertinib (80mg os die) in advanced T790M-positive NSCLC progressed to prior EGFR-TKI. Patients were considered eligible to osimertinib if T790M positive on tissue or plasma samples. In our patients, EGFR molecular testing on blood sample was conducted with digital droplet PCR (ddPCR). RESULTS: We report our experience of five patients treated with osimertinib after T790M detection on liquid biopsy that presented a disease progression at first tumor assessment mediated by SCLC transformation, as evidenced at tissue re-biopsies. All patients showed low ratio T790M/activating mutation in the blood before osimertinib (lower than 0.03). For three patients, EGFR mutational analysis was T790M-negative when re-assessed by using a less sensitive method (therascreen®) on the same liquid biopsy sample analysed by ddPCR before osimertinib therapy. CONCLUSION: Although liquid biopsy is a relevant tool to diagnose T790M presence in NSCLC patients resistant to EGFR-TKI, in case of a low ratio T790M/activating mutation, tissue biopsy should be considered to exclude the presence of SCLC transformation and/or other concomitant resistance mechanisms.

ERCC1/BRCA1 expression and gene polymorphisms as prognostic and predictive factors in advanced NSCLC treated with or without cisplatin.

BACKGROUND: The FAST was a factorial trial in first-line treatment of advanced non-small-cell lung cancer (NSCLC), addressing the role of replacing cisplatin with a non-platinum agent. The prognostic and predictive effect of ERCC1/BRCA1 expression and ERCC1/XPD/XRCC1-3 gene polymorphisms on outcomes of patients was examined. METHODS: Patients were randomised to receive treatment with or without cisplatin. ERCC1/BRCA1 expression was determined by immunohistochemistry. ERCC1 (C8092A, C118T), XPD (Lys751Gln), XRCC1 (Arg399Gln) and XRCC3 (Thr241Met) gene polymorphisms were evaluated on tumour DNA by TaqMan allelic discrimination assay. RESULTS: Tumour samples were available from 110 of 433 patients enrolled: 54.7% were ERCC1 positive and 51.4% were BRCA1 positive. Overall, ERCC1-negative patients had better response rate (P=0.004), progression-free survival (P=0.023) and overall survival (P=0.012) compared with positive ones, with no statistically significant treatment interaction. The BRCA1-positive patients showed numerically better outcomes, although not statistically significant, with no treatment interaction. Among DNA repair gene polymorphisms, only XRCC1 Gln/Gln genotype evidenced a potential prognostic role (P=0.036). CONCLUSION: This study confirms the prognostic role of ERCC1 expression and XRCC1 (Arg399Gln) polymorphism in advanced NSCLC treated with first-line chemotherapy. None of these biomarkers was shown to be a specific predictive factor of cisplatin efficacy.

Structural and spectroscopic properties of pure and doped Ba6Ti2Nb8O30 tungsten bronze.

Pure and doped Ba(6)Ti(2)Nb(8)O(30) (BTN), obtained by substituting M = Cr, Mn, or Fe on the Ti site (Ba(6)Ti(2-x) M(x)Nb(8)O(30), x = 0.06 and 0.18) and Y and Fe on the Ba and Ti sites, respectively (Ba(6-x)Y(x)Ti(2-x)Fe(x)Nb(8)O(30), x= 0.18), are synthesized. The influence of cation doping on the local structure, the cation oxidation state, and the possible defect formation able to maintain the charge neutrality are investigated by spectroscopic (electron paramagnetic resonance (EPR) and micro-Raman), structural (X-ray powder diffraction) and transport (impedance spectroscopy, thermoelectric power) measurements, in the temperature range of 300-1200 K in air and N(2) flow. Starting from the valence state of the doping ions (Fe(3+), Cr(3+), and Mn(2+)), determined by EPR, and from thermoelectric power measurements, evidencing a negative charge transport, different charge-compensating defect equilibria, based on the creation of positive electron holes or oxygen vacancies and electrons, are discussed to interpret the conductivity results.

Ferromagnetism on a paramagnetic host background: the case of rutile TM:TiO(2) single crystals (TM = Cr, Mn, Fe, Co, Ni, Cu).

Single crystals of TiO(2) rutile doped with Cr, Mn, Fe, Co, Ni, and Cu were grown with the flux method in a Na(2)B(4)O(7) melt. The samples, checked in their structural and phase homogeneity by x-ray diffraction and micro-Raman spectroscopy, were single-phase needle-shaped crystals several millimetres long. Paramagnetic and ferromagnetic behaviours at room temperature were observed and they are discussed also in connection with the magnetic properties of undoped TiO(2) crystals.

RASSF1A promoter methylation and 3p21.3 loss of heterozygosity are features of foregut, but not midgut and hindgut, malignant endocrine tumours.

The Ras-association domain family 1A (RASSF1A) tumour suppressor gene is inactivated in a variety of solid tumours, usually by epigenetic silencing of the promoter and/or allelic loss of its locus at 3p21.3. RASSF1A induces cell cycle arrest through inhibition of cyclin D1 accumulation. In this work, 62 endocrine tumours from different sites in the gut were investigated for methylation of the RASSF1A promoter using the polymerase chain reaction, the presence of 3p21.3 deletions by loss of heterozygosity analysis, and cyclin D1 expression by immunohistochemistry. Methylation was found in 20/62 (32%) cases and was restricted to foregut tumours; deletion at 3p21.3 was found in 15/58 (26%) informative cases and restricted to malignant foregut tumours; cyclin D1 hyper-expression was found in 31/58 (53%) cases and correlated with RASSF1A methylation. Our data suggest that RASSF1A is involved in the development of endocrine tumours derived from the foregut only, and that the presence of both RASSF1A methylation and 3p21.3 deletion is associated with malignancy. These results may provide a rationale for foregut-targeted therapy for aggressive endocrine carcinomas entailing the use of demethylating agents.

Transport and structural properties of pure and Cr doped Li3VO4.

This study deals with the effects of 5 and 10% chromium additions on the transport and structural properties of Li3VO4. The Cr substitution is easily obtained without impurity phases and does not affect the room- and high-temperature host crystal structure, as evidenced by X-ray powder diffraction and micro-Raman analysis. The EPR signals are interpreted in terms of quantified amounts of Cr ions in 5+ and 3+ valence states. Suitable 7Li and 51V MAS NMR spectra simulations agree with the EPR results about the relative amount of Cr5+ and Cr3+ ions substituted in V5+ and Li+ sites, respectively. The Cr3+ presence on Li site, also suggested by Raman results and Rietveld refinements, requires Li vacancies to maintain the charge neutrality. The p-type conductivity, suggested by the positive thermoelectric power coefficients, significantly increases by the cation doping up to an order of magnitude.

Progression of gastric enterochromaffin-like cells growth in Zollinger-Ellison syndrome and atrophic body gastritis patients.

BACKGROUND: Enterochromaffin-like cell hyperplasia of the gastric body mucosa occurs in hypergastrinaemic conditions such as atrophic body gastritis and Zollinger-Ellison syndrome. However, the time course of change or factors involved are not known. AIMS: To compare the rate of change of enterochromaffin-like cell proliferation in patients with atrophic body gastritis and Zollinger-Ellison syndrome. PATIENTS: From a consecutive series of atrophic body gastritis and Zollinger-Ellison syndrome patients, studied at the time of first diagnosis, 10 atrophic body gastritis (4 with pernicious anaemia) and 14 Zollinger-Ellison syndrome (4 with multiple endocrine neoplasia type 1) patients were followed-up for a median time of 48 months. METHODS: At entry and during follow-up patients underwent: plasma gastrin determination, endoscopic sampling of body mucosa for qualitative assessment of enterochromaffin-like cell hyperplasia pattern and degree of glandular atrophy, qualitative and morphometric analyses of body mucosa endocrine cells. RESULTS: At time of diagnosis, enterochromaffin-like cell lesions were more severe in atrophic body gastritis than in Zollinger-Ellison syndrome. During follow-up, no significant variations were observed in gastrin values, enterochromaffin-like cell patterns and grade of body mucosa atrophy in atrophic body gastritis. In contrast, gastrin levels were significantly increased [median 1200 (235-2625) vs 1947 (225-5200) pg/ml; p<0.001)] as was total volume density of enterochromaffin-like cells [median 1.60 (0.53-4.06) vs 3.18 (1.35-21.13)% of mucosal epithelial component; (p<0.005)] in Zollinger-Ellison syndrome. Micronodular hyperplasia of enterochromaffin-like cells, present in only one patient at diagnosis, was observed in 8 Zollinger-Ellison syndrome patients at follow-up. CONCLUSIONS: These data suggest that the progression of enterochromaffin-like cell growth in human gastric mucosa requires an increase of and/or a prolonged exposure to severe hypergastrinaemia.

Atrophic body gastritis patients with enterochromaffin-like cell dysplasia are at increased risk for the development of type I gastric carcinoid.

BACKGROUND/AIMS: In the presence of atrophic body gastritis, gastric carcinoid develops from gastric-body mucosa enterochromaffin-like cells. Few data exist on the prevalence of enterochromaffin-like dysplastic lesions in atrophic body gastritis patients and their presumed risk of evolution to carcinoid has never been assessed prospectively in humans. The aim of the present study was to investigate the prevalence and incidence of dysplastic and neoplastic enterochromaffin-like cell lesions in a consecutive series of patients with atrophic body gastritis. METHODS: A total of 130 atrophic body gastritis patients at diagnosis and 96 atrophic body gastritis patients at follow-up (median 30 months) underwent gastroscopy with multiple biopsies and fasting gastrinaemia evaluation. In patients with enterochromaffin-like cell dysplasia, a more detailed bioptic sampling at follow-up was performed. RESULTS: Of the 130 atrophic body gastritis patients, only one (0.7%) had a gastric carcinoid polyp, whereas enterochromaffin-like cell dysplasia was found in five patients (3.8%). At follow-up only one out of the 96 atrophic body gastritis patients (1%) was diagnosed as having a carcinoid polyp at 41 months. Enterochromaffin-like cell dysplasia was present in four additional patients (4.2%). Two atrophic body gastritis pernicious anaemia patients with enterochromaffin-like cell dysplasia developed a gastric carcinoid in the follow-up. Among nine atrophic body gastritis patients with enterochromaffin-like cell dysplasia, the incidence of carcinoid tumour was 22% compared to 1.1% of atrophic body gastritis patients without dysplasia (odds ratio: 26.00; 95% confidence interval: 2.089-323.52). During the follow-up, fasting gastrin levels increased significantly only in atrophic body gastritis patients with enterochromaffin-like cell dysplasia (mean 677.4 +/- 66.1 vs 1112.2 +/- 185.6; P = 0.0287). CONCLUSION: This study provides the first clinical evidence that, in hypergastrinaemic atrophic body gastritis patients, enterochromaffin-like cell dysplasia carries a markedly increased risk for development of type I gastric carcinoid. This suggests that a more detailed endoscopic/bioptic procedure in this subgroup of atrophic body gastritis patients is able to detect gastric carcinoid at an early stage.

p27: a potential main inhibitor of cell proliferation in digestive endocrine tumors but not a marker of benign behavior.

The immunohistochemical expression of the inhibitors of cyclin-dependent kinases p21 and p27 was investigated in 109 endocrine tumors of the pancreas and gastrointestinal tract and compared with that of Ki67 and p53. p21 was found to be scarcely expressed without significant differences between benign and malignant or between differentiated and undifferentiated tumors. This suggests no relationship between changes in p21 levels and clinical behavior in these endocrine tumors. p27 was found to be highly expressed in differentiated neoplasms and proved to be inversely related to Ki67 labeling (P =.02), which was usually low. These data indicate that p27 may have an important inhibiting role on the low proliferation rate of the tumors. Moreover, the protein may have a role in the resistance of differentiated endocrine tumors to chemotherapeutic agents. p27 high-expressor neoplasms were frequent in either benign (70.6%) or malignant (81.4%) differentiated tumors, thus not allowing the use of this protein for the differential diagnosis of malignant neoplasms as suggested for endocrine tumors of parathyroid and pituitary. Poorly differentiated endocrine carcinomas, which differred from the differentiated tumors for their very high Ki67 levels and frequent p53 expression, showed low or absent p21 and p27 in most cases. Classical midgut carcinoids were characterized by a sharp discrepancy between malignant behavior and very bland proliferative pattern, with Ki67 and p27 expressions similar to that of benign tumors.

The antral mucosa as a new site for endocrine tumors in multiple endocrine neoplasia type 1 and Zollinger-Ellison syndromes.

Carcinoid tumors were identified in the antro-pyloric mucosa of four patients with multiple endocrine neoplasia type 1 (MEN-1)/Zollinger-Ellison syndrome, accounting for 8.7% of 46 patients with this condition examined by endoscopy and histology. In contrast, no tumors were found in the antral biopsies from 124 cases of sporadic Zollinger-Ellison syndrome (P < 0.001), indicating a prominent role for the MEN-1 gene defects in tumor development. Immunohistochemically the tumors did not express the hormones produced by antral endocrine cells (gastrin, somatostatin, serotonin). In contrast, two of them were diffusely immunoreactive for the isoform 2 of the vesicular monoamine transporter (VMAT-2), a marker specific for the gastric nonantral enterochromaffin-like (ECL) cells. In one of these patients a second antral VMAT-2-positive carcinoid was seen 21 months after the first diagnosis. The other two antral carcinoids were unreactive for VMAT-2. Multiple ECL cell tumors were found in the gastric body-fundus mucosa of the two patients with VMAT-2-positive, but not in those with VMAT-2-negative, antral carcinoids. In one case, the former tumors were diagnosed 22 months after the detection of the antral tumor. We conclude that the antral mucosa is an additional tissue that may harbor endocrine tumors in MEN-1 syndrome. These tumors did not express the phenotype of normal antral endocrine cells and, in at least two cases, were identified as ectopic ECL cell carcinoids.

Sampling strategies for analysis of enterochromaffin-like cell changes in Zollinger-Ellison syndrome.

To investigate the optimum number of biopsy specimens to be obtained for enterochromaffin-like (ECL) cell monitoring in hypergastrinemic patients and ECL cell regional variations potentially influencing the results, qualitative ECL cell changes were assessed in 149 patients with Zollinger-Ellison syndrome using jumbo biopsy specimens and a systematic sampling procedure of 4 areas each from the lesser or greater curvature of the gastric body. Of 1,176 specimens examined, 1,101 were adequate. The correlation was excellent between different sites within the greater or lesser curvature. In contrast, a normal ECL cell pattern was more frequent in the lesser curvature, whereas linear hyperplasia was more frequent in the greater curvature. Dysplastic lesions and carcinoid tumors in endoscopically unremarkable mucosa were detected in 3.4% and 1.2% of biopsy specimens, respectively, and were equally distributed between the lesser and greater curvature. Their chances of being diagnosed were related to the number of specimens examined. Extensive sampling of both the lesser and greater curvature is recommended for early diagnosis of dysplastic and/or carcinoid lesions in patients at risk. In contrast, limited sampling in the greater curvature seems to be adequate in patients with no risk for carcinoid development.

Classification of gastric endocrine cells at the light and electron microscopical levels.

This review discusses the current concepts for the classification of gastric endocrine cells subdivided according to the type of mucosa in which they are located. In the oxyntic mucosa, the most important cell type is the ECL cell, involved in the synthesis and secretion of histamine. Proteins involved in many aspects of the biology of ECL cells including the response to the gastrin stimulus, membrane transport and docking, prevention of apoptosis, calcium homeostasis, autocrine activity, and maintenance of the differentiated cell phenotype have been localized to this cell type. Other cells of the oxyntic mucosa include: the D and EC cells producing somatostatin and serotonin, respectively, delivered through long cell processes; the X (or A-like) cells, possibly producing endothelin; and the D(1) and P cells of unknown function and possibly representing morphological variants of other cell types. In the antral mucosa, the three important cell types are represented by: the gastrin-producing G cells; the somatostatin-producing D cells, which are anatomically and functionally associated with G cells; and the serotonin-producing EC cells, which are located at the bottom of antral glands.

Intramucosal cysts in the gastric body of patients with Zollinger-Ellison syndrome.

To ascertain the frequency and the clinico-functional correlations of intramucosal cysts in the gastric body of patients with the Zollinger-Ellison syndrome (ZES) and to clarify the relevant mechanism of development, a total of 106 consecutive ZES patients (58 M, 48 F; mean age: 53 yrs, range 19-93 yrs) were investigated with a mean of 7.2 biopsy specimens of the body mucosa per patient proved to be suitable for the study. Biopsies of endoscopically detectable polypoid lesions were not considered. Cystic changes were evaluated with respect to their severity by assessing the cyst grade (0, absent, 1; <30%, 2; 30-60%; 3 >60% of the mucosal area of the biopsy specimen of individual patients showing the most pronounced finding, respectively) and to their intragastric distribution by assessing the ratio of biopsy specimens showing cystic changes over the total number of biopsies examined in each patient. Intramucosal cysts were found in biopsies of non-polypoid gastric body mucosa in 71.7% of 106 patients with Zollinger-Ellison syndrome (ZES) and showed grade 2 and 3 severity in 22 and 8 cases, respectively. The severity of cystic changes correlated with the gastrin levels (p = 0.0005) and was more advanced in patients with active than in those with cured disease (p = 0.037). In the former group, furthermore, advanced cystic changes correlated with age (p = 0.03), male gender (p = 0.014), years of disease from onset (p < 0.02), years of omeprazole treatment (p = 0.033), basal acid output (p < 0.02), severity of ECL cell proliferative changes (p = 0.028), and absence of previous gastrinoma resection (p = 0.039) whereas they did not correlate with MEN-1 status, gastritis, maximal acid output, total duration of any antisecretory drug treatment, daily doses of omeprazole (> 20 mg vs 20 mg), years from surgery, duodenal localization of gastrinoma(s), presence of gastric carcinoid tumor(s) and of liver metastases. In groups of patients subdivided according to three levels of serum gastrin, the duration of omeprazole treatment was not related to the severity of cystic changes. It is concluded that intramucosal cysts in non polypoid gastric body mucosa of ZES patients are by far more common than the already reported fundic gland polyps, to which they likely give raise. Circulating levels of gastrin have an important independent role in their development.

ECL cell tumor and poorly differentiated endocrine carcinoma of the stomach: prognostic evaluation by pathological analysis.

BACKGROUND & AIMS: Gastric endocrine tumors show a wide spectrum of clinical behavior, and prognostic assessement of individual tumors is difficult. The aims of this work were to identify predictors of tumor malignancy and patient outcome and to provide a rationale for treatment guidelines. METHODS: Gastric endocrine tumors (86 enterochromaffin-like cell carcinoids and 16 poorly differentiated carcinomas) were investigated for 15 clinicopathologic variables and for expression of Ki67, P53, and BCL-2 proteins. Data were analyzed by univariate and multivariate statistics for evidence of tumor malignancy and patient survival. RESULTS: Histological grades 2 and 3, size >/=3 cm, 9 or more mitoses, or >/=300 Ki67-positive cells per 10 high-power fields identified 26 of 33 (79%) malignant (metastatic or deeply invasive) tumors, and size <1 cm and/or growth restricted to the mucosa characterized 46 of 69 (67%) tumors with benign behavior during a median follow-up of 39 months. Malignancy-predictive models were developed using angioinvasion, size, clinicopathologic type, mitotic index, and Ki67 index. The same variables, in addition to deep gastric wall invasion and histological grade, predicted patient outcome. CONCLUSIONS: Criteria for the assessment of malignancy risk and patient outcome were developed for the different tumors, providing a basis for treatment guidelines.

Functioning human insulinomas. An immunohistochemical analysis of intracellular insulin processing.

Sixty-seven insulinomas were investigated by immunohistochemistry using site-directed antibodies against insulin, proinsulin, chromogranin A, HISL-19, and four proteins directly or indirectly involved in the proteolytic processing of proinsulin: the prohormone convertases PC2 and PC3, carboxypeptidase H (CPH) and 7B2. Results were expressed in a six-grade score according to the frequency of immunoreactive tumour cells. Insulin was expressed by all tumours, appearing in either a diffuse or a polarized pattern and being detected in more than 30% of tumour cells in all cases but three. Proinsulin was also expressed in all tumours, with more than 50% of tumour cells immunoreactive in all cases but 5. It was consistently localized in the Golgi apparatus. In about half the cases, moreover, it also showed diffuse cytoplasmic staining, usually with a very sparse distribution. Trabecular and solid insulinomas did not present specific, homogeneous patterns of insulin immunostaining. However, insulin immunoreactivity was much more abundant in trabecular than in solid neoplasms, being present in virtually all tumour cells (score 6) in 50% and 8% of cases, respectively. Virtually all insulinomas expressed PC2, PC3, CPH and 7B2, usually in 30-100% of tumour cells, with a frequency significantly related to that of insulin. However, detection of PC2 and 7B2 was slightly less frequent than that of PC3 and CPH. In consecutive sections these proteins were found to be mostly co-localized with insulin and chromogranin A but not with proinsulin. They were heavily expressed in all 10 tumours with more than 10% of cells showing cytoplasmic proinsulin immunoreactivity, indicating that the leakage of proinsulin from the Golgi compartment is not associated with faulty expression of converting enzymes and possibly reflects a saturated processing capacity. HISL-19 immunoreactivity was found in both Golgi apparatus and insulin stores, indicating that the relevant antigen is different from all other proteins investigated. These results do not support a defect in expression or localization of proinsulin-processing enzymes in most insulinomas.

Expression of the alpha- and beta-subunits of human chorionic gonadotropin by subsets of parathyroid cells in states of hyperparathyroidism.

The alpha-subunit of human chorionic gonadotropin (hCG-alpha) has previously been found to be expressed in hyperplasias and tumours of numerous endocrine tissues including all those involved in MEN-I syndrome except the parathyroid glands. In the present immunohistochemical investigation of 86 patients with various states of hyperparathyroidism, expression of hCG-alpha by subsets of parathyroid cells was shown in 46 cases (54 per cent) including all states of hyperparathyroidism investigated: primary adenoma (n = 34, 44 per cent); uraemic secondary hyperplasia (n = 34, 53 per cent); MEN-I (n = 13, 77 per cent); MEN-II (n = 2, 100 per cent); and parathyroid carcinoma (n = 3, 100 per cent). Although the number of parathyroid cells expressing hCG-alpha was in general low, the occurrence of numerous immunoreactive cells appeared to be concentrated in primary adenoma and MEN-I (20 and 33 per cent of positive cases, respectively). No expression was found in ten normal control glands, except for very rare cells in one case. Expression of hCG-alpha was in part associated with that of hCG-beta, which appeared to be more commonly expressed than hCG-alpha in cases of secondary hyperparathyroidism. In separate experiments, Bouin fixation was found to preserve the immunoreactivity of hCG-alpha and hCG-beta better than the formalin fixation used in this study, suggesting that the figures may be underestimates. These immunohistochemical results are in agreement with a previous biochemical study showing hCG-alpha and hCG-beta in extracts of parathyroid tumours and extend to the parathyroid glands the otherwise ubiquitous finding of hCG-alpha expression in MEN-I-related neoplasms.

Pathogenesis of ECL cell tumors in humans.

In ECL cell tumors developed in the setting of hypergastrinemic conditions (ECL cell carcinoids type 1 and 2), hypergastrinemia is the dominant agent acting as a promoter in all steps (hyperplasia-dysplasia-neoplasia) of the tumorigenic sequence. In contrast, it apparently lacks transforming properties as shown by the absence of ECL cell carcinoids in patients exposed to hypergastrinemia alone, i.e., those with sporadic Zollinger-Ellison syndrome. The potential transforming factors include: the allelic loss of the MEN-1 suppressor gene in the genetically predisposed MEN-1 patients, an alteration that may induce ECL cell tumors even in the absence of hypergastrinemia; the still unknown factor(s) associated with atrophic corporal gastritis; agents whose role in the induction of human ECL cell tumors is still unclarified, such as basic Fibroblast Growth Factor, human Chorionic Gonadotropin-alpha and Transforming Growth Factor-alpha; and agents having a favoring role on the ECL exposure to mitogens such as BCL-2. No information is currently available on the pathogenesis of gastrin-independent, sporadic ECL cell carcinoids (type 3) or of gastric neuroendocrine carcinomas.

Aggressive forms of gastric neuroendocrine tumors in multiple endocrine neoplasia type I.

In recent classifications of gastric endocrine tumors, tumors arising in patients with multiple endocrine neoplasia type 1 (MEN-1) are regarded to be regulated by the concomitant hypergastrinemia resulting from to pancreatic or, most commonly, duodenal gastrinomas and to have a benign behavior. In this article, we report on two cases of MEN-1 gastric neuroendocrine tumors having a fatal course. Case 1 was a young male with hyperparathyroidism and Zollinger-Ellison syndrome and with florid development of multiple gastric carcinoids and multiple duodenal gastrinomas. Metastases occurred in the liver, of exclusive gastric origin, in periduodenal lymph nodes, of exclusive duodenal origin, and in perigastric lymph nodes, of mixed origin. The patient died 48 months after diagnosis. Case 2 was an adult female patient with hyperparathyroidism, adrenocortical disorders, and gastric tumors but no hypergastrinemia. The patient died 3 months after tumor diagnosis. At autopsy, the stomach showed multiple benign carcinoids and two independent neuroendocrine carcinomas not reported before in MEN-1 and massively metastatizing to lymph nodes, liver, and peritoneum. Multiple islet cell tumors mostly producing pancreatic polypeptide were found, whereas gastrinomas were seen in neither the pancreas nor the duodenum. Allelic losses at the MEN-1 gene locus in chromosome 11q13, the mechanism responsible for tumor development in MEN-1 syndrome, were demonstrated in the carcinoid tumors of case 1 and in the neuroendocrine carcinoma of case 2. We conclude that gastric neuroendocrine tumors in patients with MEN-1 may have a poor outcome, they have the same genetic mechanism as MEN-1 tumors in other organs, and they may be independent of the trophic effect of hypergastrinemia.