Development of amplified luminescent proximity homogeneous assay for quantitation of gastrin-17.

A highly sensitive and convenient amplified luminescent proximity homogeneous assay (AlphaLISA) method with high throughput and automation potential was developed for quantitation of serum Gastrin-17 (G-17) levels, which can facilitate the early diagnosis of atrophic gastritis in people at high risk of gastric cancer using a non-invasive approach. In this study, donor and acceptor beads with modified carboxyl groups on the surface were directly coupled to anti-G-17 antibodies through activation was proposed for application in the development of the new AlphaLISA, which can effectively simplify the steps and shorten the reaction time to achieve faster detection. Therefore, the G-17-AlphaLISA only needs to react for 15 min to obtain good analysis results. The proposed method has a wider detection range than commercial enzyme-linked immunosorbent assay (ELISA) kits (0.12-112.8 pmol/L > 0.5-40 pmol/L). In addition, results of G-17-AlphaLISA and ELISA had good correlation and agreement (ρ = 0.936). Importantly, the developed method may be more suitable for the large-scale screening of people at high risk for gastric cancer than traditional ELISA and provides a novel solution for other biomarkers that require accurate, highly sensitive, and high throughput detection.

Metastatic Patterns of Duodenopancreatic Neuroendocrine Tumors in Patients With Multiple Endocrine Neoplasia Type 1.

Patients with multiple endocrine neoplasia 1 syndrome (MEN1) often develop multifocal duodenopancreatic neuroendocrine tumors (dpNETs). Nonfunctional pancreatic neuroendocrine tumors (PanNETs) and duodenal gastrinomas are the most frequent origins of metastasis. Current guidelines recommend surgery based on tumor functionality, size ≥2 cm, grade or presence of lymph node metastases. However, in case of multiple primary tumors it is often unknown which specific tumor metastasized. This study aims to unravel the relationship between primary dpNETs and metastases in patients with MEN1 by studying endocrine differentiation. First, it was shown that expression of the endocrine differentiation markers ARX and PDX1 was concordant in 18 unifocal sporadic neuroendocrine tumors (NETs) and matched metastases. Thereafter, ARX, PDX1, Ki67 and gastrin expression, and the presence of alternative lengthening of telomeres were determined in 137 microscopic and macroscopic dpNETs and 36 matched metastases in 10 patients with MEN1. ARX and PDX1 H-score clustering was performed to infer relatedness. For patients with multiple metastases, similar intrametastases transcription factor expression suggests that most metastases (29/32) originated from a single NET of origin, while few patients may have multiple metastatic primary NETs. In 6 patients with MEN1 and hypergastrinemia, periduodenopancreatic lymph node metastases expressed gastrin, and clustered with minute duodenal gastrinomas, not with larger PanNETs. PanNET metastases often clustered with high grade or alternative lengthening of telomeres-positive primary tumors. In conclusion, for patients with MEN1-related hypergastrinemia and PanNETs, a duodenal origin of periduodenopancreatic lymph node metastases should be considered, even when current conventional and functional imaging studies do not reveal duodenal tumors preoperatively.

Gastrin Staining in Inflamed Stomach Biopsies Labeled as "Antral" Rarely Detects Atrophic Gastritis.

OBJECTIVES: Autoimmune metaplastic atrophic gastritis (AMAG) is an underrecognized entity, especially in its early stage. This study assessed whether the use of gastrin immunohistochemistry would increase sensitivity for diagnosing early AMAG. METHODS: Three-hundred gastric biopsies were prospectively stained for gastrin by immunohistochemistry. Inclusion criteria included well-oriented gastric mucosa with mucus glands and minimal plasma cell infiltrate not suspected to represent pyloric metaplasia. Patient age, sex, designated location of biopsy, presence or absence of intestinal metaplasia, and clinical information were not criteria. Any case with absence of gastrin-positive endocrine cells reflexed to chromogranin immunohistochemistry. Maloriented biopsies or cases with current Helicobacter infection were excluded. RESULTS: The 298-patient study cohort comprised 222 females (mean age, 47 years; range, 16-80 years) and 76 males (mean age, 49 years; range, 7-80 years). Biopsies were designated as "antral/antral nodules" (61%), and the rest were labeled "gastric/random stomach" (39%). Nine cases (3%) exhibited absence of gastrin-positive endocrine cells; one of those showed endocrine cell hyperplasia by chromogranin staining. CONCLUSIONS: Pathologists should be aware of the histologic features of early AMAG and meticulously analyze tissue regardless of specimen labeling. Gastrin immunostain is a supplemental diagnostic tool when encountering inflamed antral-appearing specimens.

Metastatic gastrinoma in the breast mimicking primary solid papillary carcinoma.

We report a case of metastatic gastrinoma to the breast morphologically mimicking solid papillary carcinoma of the breast. A 59-year-old woman presented with a hypoechoic right breast mass that histologically revealed solid nests of small monotonous tumor cells, fibrovascular cores, and round to oval nuclei with fine chromatin and small nucleoli. Immunohistochemistry demonstrated chromogranin and synaptophysin positivity. Tumor prognostic markers showed weak positivity for estrogen receptor and negativity for progesterone receptor. Although an initial diagnosis of solid papillary carcinoma was rendered, subsequent identification of the patient's clinical history of pancreatic gastrinoma and an additional immunohistochemical stain for gastrin supported a diagnosis of metastatic gastrinoma. We report this rare case to increase awareness of metastatic neuroendocrine tumors in the breast. Multiple breast lesions and lack of expression of estrogen/progesterone hormone receptors should prompt careful review of the patient's clinical history to rule out metastatic neuroendocrine disease.

Study of clinicopathological features, hormone immunoexpression, and loss of ATRX and DAXX expression in pancreatic neuroendocrine tumors.

OBJECTIVES: Neuroendocrine tumors of the pancreas (PanNETs) are rare neoplasms, and not much is known about their pathogenesis. We aimed to evaluate ATRX/DAXX immunoexpression in PanNETs a cohort of well-characterized PanNETs. METHODS: PanNETs diagnosed over a 10-year period were retrieved and clinicopathogical features reviewed. Immuohistochemistry for pancreatic hormones, and for ATRX and DAXX was performed. RESULTS: Sixty-eight PanNETs were included (30 males and 38 females) with median age of 39 years. Histologically, there were 37 Grade 1 (54.4%), 27 Grade 2 (39.7%), and 4 Grade 3 (5.9%) cases. On immunostaining for hormones, insulin expression was most frequent (22 cases; 38.6%), followed by gastrin (7 cases; 12.3%); 25 cases (43.9%) were negative for all hormones. Loss of ATRX/DAXX immunoexpression was noted in 18 cases (39.1%), and was significantly more frequent in tumors larger than 5 cm. Lymphovascular invasion, infiltrative borders, and infiltration of adjacent organs were also more frequent in tumors with loss of ATRX/DAXX immunoreactivity. A little over half the tumors with ATRX/DAXX loss showed negative immunostaining for all hormones (55.6%). CONCLUSION: Loss of ATRX/DAXX expression is frequent in PanNETs, indicating a role in their pathogenesis. As ATRX/DAXX loss is more frequent in larger tumors, and in those with lymphovascular invasion, adjacent organ infiltration and infiltrative borders, this suggests that loss of ATRX/DAXX expression is a late event in pathogenesis and is associated with an aggressive phenotype. Immunohistochemical detection of ATRX/DAXX loss is a simple method for ATRX/DAXX evaluation and can easily be incorporated into routine pathological evaluation of PanNETs.

Síndrome de zolinger - Elison / Syndrome of Zolinger - Elison

Resumen:El síndrome de Zollinger - Ellison es una endocrinopatía que fue descrita en 1955 por los doctores Robert Zollinger y Edwin Ellison, quienes propusieron la triada diagnóstica que incluye hipersecreción gástrica ácida, úlcera péptica y gastrinoma. Esta enfermedad predomina en mujeres entre los 50 y 60 años de edad. Según su etiología, este síndrome se clasifica en una forma esporádica o asociada a neoplasia endocrina múltiple tipo 1 (NEM - 1).Más de la mitad de los gastrinomas se localizan en la pared duodenal, el páncreas es la segunda ubicación en frecuencia. Existen localizaciones ectópicas en ovario, mesenterio, hígado y ducto biliar. A nivel histopatológico se encuentran células tumorales redondas, con núcleos pequeños y nucléolos prominentes. La hipersecreción ácida gástrica está asociada a un defecto en la inhibición del retrocontrol negativo de la somatostatina sobre las células G antrales productoras de gastrina. Clínicamente, los pacientes manifiestan dolor abdominal, diarrea, pirosis, náuseas y vómitos; relacionados principalmente a la formación de úlceras pépticas. El diagnóstico debe incluir una medición en los niveles séricos de gastrina y valores de pH gástrico. El tratamiento de primera línea es la terapia antisecretora, principalmente con inhibidores de la bomba de protones. Los estudios de imágenes son deutilidad para detectar metástasis y evaluar la enfermedad quirúrgicamente resecable. Se debe hacer diagnóstico diferencial con otros tumores neuroendocrinos y causas de hipergastrinemia.

Abstract:Zollinger - Ellison syndrome is an endocrinopathy that was first described in 1955 by doctors Robert Zollinger and Edwin Ellison, who proposed the diagnostic triad that includes gastric acid hypersecretion, peptic ulcer and gastrinoma. This disease predominates in women between 50 and 60 years old. Based on the etiology, the syndrome is classified in sporadic or associated with multiple endocrine neoplasia type 1 (NEM - 1). Over half of gastrinomas are located in the duodenal wall, the pancreas is the second frequency location. There are ectopic locations, such as ovary, mesentery, liver and bile duct. Round cells, small nuclei and prominent nucleoli, are the main hispathologycal characteristics. Gastric acid hypersecretion is associated with a defect in the negative feedback inhibition of somatostatin on G antral gastrin-producing cells. Clinically, patients present abdominal pain, diarrhea, heartburn, nausea and vomiting; primarily related to the development of peptic ulcers. Diagnosis includes a measurement in serum gastrin levels and gastric pH values. The first line treatment is the antisecretory therapy, primarily proton-pump inhibitor. Imaging studies are useful to detect metastases and evaluate the surgically resectable disease. Neuroendocrine tumors and hypergastrinemia causes are the main differential diagnoses, the clinician should consider.

A mathematical model to predict protein wash out kinetics during whole-lung lavage in autoimmune pulmonary alveolar proteinosis.

Whole-lung lavage (WLL) remains the standard therapy for pulmonary alveolar proteinosis (PAP), a process in which accumulated surfactants are washed out of the lung with 0.5-2.0 l of saline aliquots for 10-30 wash cycles. The method has been established empirically. In contrast, the kinetics of protein transfer into the lavage fluid has not been fully evaluated either theoretically or practically. Seventeen lungs from patients with autoimmune PAP underwent WLL. We made accurate timetables for each stage of WLL, namely, instilling, retaining, draining, and preparing. Subsequently, we measured the volumes of both instilled saline and drained lavage fluid, as well as the concentrations of proteins in the drained lavage fluid. We also proposed a mathematical model of protein transfer into the lavage fluid in which time is a single variable as the protein moves in response to the simple diffusion. The measured concentrations of IgG, transferrin, albumin, and ß2-microglobulin closely matched the corresponding theoretical values calculated through differential equations. Coefficients for transfer of ß2-microglobulin from the blood to the lavage fluid were two orders of magnitude higher than those of IgG, transferrin, and albumin. Simulations using the mathematical model showed that the cumulative amount of eliminated protein was not affected by the duration of each cycle but dependent mostly on the total time of lavage and partially on the volume instilled. Although physicians have paid little attention to the transfer of substances from the lung to lavage fluid, WLL seems to be a procedure that follows a diffusion-based mathematical model.

Tumour gastrin expression and serum gastrin concentrations in dogs with gastric carcinoma are poor diagnostic indicators.

Hypergastrinaemia is observed commonly in human patients with gastric carcinoma and is associated with atrophic gastritis and Helicobacter pylori infection, both of which predispose to development of gastric tumours. Increased expression of gastrin is also described as a prognostic indicator for gastric carcinoma in man. Gastric carcinoma is rare in dogs and generally carries a grave prognosis. In this study, the expression of gastrin was investigated immunohistochemically in gastric biopsy samples from 64 dogs with gastric carcinoma. Serum gastrin concentrations were measured in 15 of these dogs and compared with those of seven healthy control dogs. Tumour tissue expressed gastrin in 8% (5/64) of the dogs with gastric carcinoma. There was no significant difference in serum gastrin concentrations between dogs with gastric carcinoma and healthy controls (P = 0.08). Expression of gastrin in gastric carcinomas is less common in dogs than in man and may therefore not be relied on as a prognostic marker in this species. Serum gastrin concentration alone is also not a useful biomarker for gastric carcinoma in dogs.

The effects of chronic bile reflux on the gastric mucosa of rats.

BACKGROUND/AIMS: To establish a rat model mimicking human bile reflux for studying the pathological effects of chronic bile reflux. MATERIALS AND METHODS: The duodenum of Sprague-Dawley rats was transected below the opening of the common bile duct, and a gastrojejunostomy was performed at the greater curvature of the forestomach. After the rats demonstrated bile reflux for 1 year, we studied the pathological features of the glandular stomach and forestomach mucosa. We also studied the effect of bile reflux on gastrin expression in the glandular stomach mucosa by using immunohistochemistry. RESULTS: Chronic bile reflux caused significant hyperplasia and expansion of gastric glands in the glandular stomach. Dysplasia and cancer formation also developed, but the incidence was significantly lower than that reported in the literature. Intestinal metaplasia and ulceration in the glandular stomach were also rare. In the forestomach, the squamous epithelium showed significant hyperplasia and keratinization along with keratin pearls and keratocysts. Intestinal metaplasia was rare and no tumorigenesis was observed. Chronic bile reflux significantly increased gastrin expression in the glandular stomach mucosa. CONCLUSIONS: When simulating the physiological bile reflux pathway, chronic bile reflux caused hyperplasia and expansion of gastric glands in the glandular stomach and squamous epithelial hyperplasia and keratinization in the forestomach.

Gut peptide profile and chemotherapy-associated dyspepsia syndrome in patients with breast cancer undergoing FEC60 chemotherapy.

AIM: The association of motilin, ghrelin, leptin, gastrin, pepsinogen (PG) I and II with cancer chemotherapy-associated dyspepsia syndrome (CADS) was investigated in 35 patients with breast cancer receiving first cycle of 5-fluorouracil, cyclophosphamide, epirubicin (FEC60) chemotherapy. PATIENTS AND METHODS: The onset of dyspeptic symptoms on days 3 and 10 after chemotherapy identified patients with and without CADS. Gastrointestinal symptoms were scored with the Gastrointestinal Symptom Scoring Rate (GSRS) questionnaire. Gastrointestinal peptides were evaluated by enzyme-linked immunosorbent assay. RESULTS: Twenty-one patients (60%) had CADS. The area under the curve (AUC) of ghrelin was higher, whereas that of PGI, PGII and motilin were lower in patients with CADS compared to those without. In patients with CADS, the AUC of PGI and PGII negatively correlated with the GSRS indigestion cluster. CONCLUSION: Impairment of gastrointestinal motility suggested by low motilin concentrations and mucosal damage mirrored by an increase of ghrelin seem to be involved in the onset of CADS in patients during chemotherapy for breast cancer.

Characterization of gastrins and their receptor in solid human gastric adenocarcinomas.

OBJECTIVE: The gastrin and the gastrin/CCK-B receptor genes are co-expressed in several carcinomas. The primary translational product, progastrin, however, is processed to several peptides of which only those that are α-amidated at their C-terminus are receptor ligands. So far, characterization of the progastrin-derived peptides in gastric cancer has not been reported. The authors therefore examined the molecular nature of gastrin and its receptor in human gastric carcinomas. MATERIALS AND METHODS: Twenty patients with adenocarcinoma underwent partial or total gastrectomy. In samples from each carcinoma, gastrin peptides were characterized, using a library of sequence-specific immunoassays. Expression was also demonstrated by immunohistochemistry. In addition, the gastrin and gastrin/CCK-B receptor gene expression was quantitated using real-time PCR, and the receptor protein demonstrated by western blotting. RESULTS: α-Amidated gastrins were detectable in 16 of 20 carcinomas (median concentration 2.1 pmol/g tissue; range 0-386 pmol/g tissue). The tissue concentrations correlated closely to the gastrin mRNA contents (r = 0.75, p < 0.0001). Moreover, progastrin and non-amidated processing intermediates, including glycine-extended gastrins, were detected in 19 carcinomas. Immunohistochemistry corroborated gastrin expression in carcinoma cells. Chromatography revealed extensive progastrin processing with α-amidated gastrin-34 and -17 (tyrosyl-sulfated as well as non-sulfated) as major products. Finally, gastrin/CCK-B receptor mRNA and protein were detected in all tumors. CONCLUSIONS: The results show that the elements for a local loop of α-amidated gastrins and their receptor are detectable in 80% of human gastric adenocarcinomas. Therefore, the results support the contention that locally expressed gastrin may be involved in the tumorigenesis of gastric adenocarcinomas.

Etiological factors of duodenal and gastric ulcers.

BACKGROUND/AIMS: We aimed to determine the etiology of patients with duodenal and gastric ulcers. METHODS: 140 patients diagnosed with peptic ulcer between April 2002-2009 were enrolled in this prospective study. Two biopsy specimens were collected from the antrum and corpus for histology and one for rapid urease testing, and stool samples were analyzed for Helicobacter pylori antigen. Serum calcium and gastrin levels were also analyzed. RESULTS: 82 (58%) patients were male, with a median age of 47.70±15.03 years (range: 16-92). The ulcer was located in the duodenum in 96 patients, stomach in 40, and both duodenum and stomach in 4. The rates of patients positive for Helicobacter pylori antigen in stool, positive in urease testing and positive for Helicobacter pylori presence in antral and corpus samples were 48%, 52%, 67%, and 60%, respectively. 107 (76%) patients were positive for Helicobacter pylori in one of the test methods. 64 (46%) patients had a history of nonsteroidal antiinflammatory drug use within the last month. Mean levels of calcium and gastrin were 9.29±0.40 (7.90-10.20) and 73.96±89.88 (12.86-562.50), respectively. Gastrin level was correlated to inflammatory activity (p<0.05). 19 (13.6%) of the patients were negative for Helicobacter pylori, nonsteroidal anti- inflammatory drug use and hypersecretory illness, and were classified as idiopathic. CONCLUSIONS: The most common cause of duodenal and gastric ulcer was Helicobacter pylori, and it was responsible for three-fourths of the cases. About half of the patients had a history of nonsteroidal antiinflammatory drug use, and nonsteroidal antiinflammatory drug and Helicobacter pylori were both responsible for the ulcer in three-fourths of these patients. In about one-tenth of the patients, nonsteroidal antiinflammatory drug use was the cause of ulcer alone, and about one-tenth of the ulcers were classified as idiopathic.

Endocrine cells in the human common bile duct in patients with obstructive jaundice.

BACKGROUND/AIMS: There was no data about endocrine cells in the extrahepatic bile duct in secondary cholangitis due to obstructive jaundice. The aim of the present study is to investigate immunohistochemically the endocrine cell types in the lower part of the human common bile duct in biopsy samples, collected during drainage because of complete or incomplete obstruction, caused mainly by stones. We explained the presence of various hormone-producing endocrine cells in this region with the regulation of physiological and pathological processes there. METHODOLOGY: We used light and electron microscopic immunohistochemistry. RESULTS: More gastrin-positive, somatostatin-positive, secretin-positive, serotonin-positive, chromogranin- A-positive and synaptophysin-positive endocrine cells were found compared to control preparations. CONCLUSIONS: Occurrence of endocrine cells may relate to disturbed bile flow and to formation of calculi. Endocrine cell hyperplasia may be related to longstanding inflammation as in chronic cholecystitis and all secreted hormones from the described ECs can support pathologic process in the choledochus, i.e. inflammation, increased mucus secretion, fibrosis, muscle contraction, etc. We may state that various ECs (similar to those in duodenum) present in the lower part of the large bile duct and their hormones exert action on physiology (motility, secretion) and pathology (inflammation and fibrosis) in that part of the biliary tree.

Role of endogenous cholecystokinin on growth of human pancreatic cancer.

Cholecystokinin (CCK) and gastrin stimulate growth of pancreatic cancer. Although down-regulation of gastrin inhibits growth of pancreatic cancer, the contribution of endogenous CCK to tumor growth is unknown. The purpose of this study was to evaluate the role of endogenous CCK on autocrine growth of pancreatic cancer. Pancreatic cancer cell lines were analyzed for CCK mRNA and peptide expression by real-time RT-PCR and radioimmunoassay, respectively. The effect of endogenous CCK on growth was evaluated by treating cancer cells with CCK neutralizing antibodies and by down-regulating CCK mRNA by RNAi. Wild-type pancreatic cancer cells expressed significantly lower CCK mRNA and peptide levels than gastrin. Neither treatment of pancreatic cancer cells with CCK antibodies nor the down-regulation of CCK mRNA and peptide by shRNAs altered growth in vitro or in vivo. Conversely, when gastrin mRNA expression was down-regulated, the same cells failed to produce tumors in spite of having sustained levels of endogenous CCK. Pancreatic cancer cells produce CCK and gastrin; however, the autocrine production of gastrin is more important for stimulating tumor growth.

Gastric lesions in patients with autoimmune metaplastic atrophic gastritis (AMAG) in a tertiary care setting.

Autoimmune metaplastic atrophic gastritis (AMAG) is an early manifestation of pernicious anemia that precedes the hematologic changes by years to decades. It is associated with metaplastic changes and neoplasms, including pyloric gland adenomas (PGAs). We investigated the frequency of PGAs and other lesions in all nonconsultation gastric biopsies and resections (1988 to 2008) diagnosed as AMAG. We further selected cases confirmed as AMAG by immunohistochemical identification of the gastric body (negative gastrin) and linear and nodular enterochromaffin-like cell hyperplasia (chromogranin). From this subset, all polyps and neoplasms were reviewed. We identified a total of 41,245 patients with gastric biopsies or resections from 46.7% males and 53.3% females comprising patients self-identified as 67.0% white, 23.6% African-American, 1.4% Asian, 0.8% non-White Hispanic, and 7.2% other or unknown. AMAG was diagnosed in 461 patients (1.1%), and had the following percentages based on race: 1.1% White, 1.3% African-American, 1.4% Asian, and 2.7% non-White Hispanic. The female:male ratio was 2:1 with an overall median age at presentation of 67.0 years. Of the 461 patients with AMAG, 143 had endoscopically identifiable lesions. These lesions (n=240) consisted of 179 polyps (138 hyperplastic polyps, 20 oxyntic mucosa pseudopolyps, 18 intestinal-type gastric adenomas, and 3 PGAs), 46 well-differentiated neuroendocrine neoplasms (carcinoid), 1 gastrointestinal stromal tumor, 3 lymphomas, and 11 adenocarcinomas. In summary, AMAG occurred with similar frequency across all racial groups. Although PGAs are associated with AMAG, they remain rare in the setting of AMAG.

Regional distribution and relative frequency of gastrointestinal endocrine cells in the ddN mice: an immunohistochemical study.

The distributions and frequencies of some endocrine cells in the eight portions of the gastrointestinal (GI) tract - fundus, pylorus, duodenum, jejunum, ileum, cecum, colon and rectum of the ddN mouse, were studied with immunohistochemical method using seven types of antisera against chromogranin (Cg) A serotonin, somatostatin, glucagon, gastrin, cholecystokinin (CCK)-8 and human pancreatic polypeptide (hPP). In the GI tract of ddN mice, CgA, serotonin, somatostatin, glucagon, gastrin, CCK-8 immunoreactive (IR) cells were identified with various frequencies, but hPP-IR cells were not observed in this study. Most of IR cells in the intestinal portion were generally spherical or spindle in shape (open type cell) whereas cells showing round in shape (close type cell) were found in the intestinal gland and stomach regions occasionally. They showed the highest frequency in the pylorus or colon. CgA-IR cells were observed from the pylorus to ileum. Serotonin-IR cells were detected throughout the whole GI tract except for the fundus. Somatostatin-IR cells were demonstrated throughout the whole GI tract except for the cecum and colon. Gastrin and CCK-8-IR cells were restricted to the pylorus and duodenum. In addition, a few glucagon-IR cells were restricted to the fundus and rectum. In conclusion, the general distribution patterns and relative frequency of GI endocrine cells of the ddN mouse was similar to that of other strains of mice. However, some strain and/or species-dependent unique distributions and frequencies of endocrine cells were also observed in the present study.

Activation of NF-kappaB is required for mediating proliferative and antiapoptotic effects of progastrin on proximal colonic crypts of mice, in vivo.

Mice overexpressing progastrin (PG) in intestinal mucosa (fatty acid-binding protein (Fabp)-PG mice) are at an increased risk of proximal colon carcinogenesis in response to azoxymethane. Here, we report a significant increase in the length of proximal colonic crypts in Fabp-PG mice, associated with potent antiapoptotic effects of PG, which likely contributed to the previously reported increase in colon carcinogenesis in Fabp-PG mice. Phosphorylation of kinase of IkappaBalpha (IKKalpha/beta), inhibitor of kappaB (IkappaB)alpha and p65NF-kappaB was significantly elevated in proximal colonic crypts of Fabp-PG versus wild-type mice, which was associated with degradation of IkappaBalpha and nuclear translocation/activation of p65. Surprisingly, distal colonic crypt cells were not as responsive to elevated levels of PG in Fabp-PG mice. Annexin II, recently described as a high-affinity receptor for PG, strongly co-localized with PG intracellularly and on basolateral membranes of proximal crypt cells, providing evidence that annexin-II binds PG in situ in colonic crypt cells. Proliferative and antiapoptotic effects of PG on proximal crypts of Fabp-PG mice were attenuated to wild-type levels, on treatment with NEMO peptide (an inhibitor of nuclear factor-kappaB (NF-kappaB) activation), demonstrating for the first time a critical role of NF-kappaB in mediating hyperproliferative affects of PG on colonic crypts of Fabp-PG mice, in vivo. Thus, downregulation of NF-kappaB may significantly reduce the increased risk of colon carcinogenesis in response to PG.