18F-FDG PET/CT imaging for a gastrointestinal mantle cell lymphoma with multiple lymphomatous polyposis

Multiple lymphomatous polyposis (MLP) is an uncommon type of gastrointestinal lymphoma characterized by the presence of multiple polyps along the gastrointestinal tract. Most of this entity is in fact considered the counterpart of gastrointestinal tract involvement for mantle cell lymphoma (MCL). To our knowledge, there have been no reports on [fluorine-18]-fluorodeoxy-glucose (¹⁸F-FDG)-positron emission tomography (PET)/computed tomography (CT) imaging for gastrointestinal MCL with MLP. We present the results of ¹⁸F-FDG PET/CT imaging in a patient with gastrointestinal tract involvement of MCL showing continuous MLP from the stomach to the rectum and intestinal intussusception. FDG-PET/CT findings were false negative in typical MLP spreading widely over the gastrointestinal tract, but uptake was noted in large lesions with deep infiltration considered atypical as MLP. On FDG-PET/CT imaging, the Ki-67 proliferative index, which is a cell proliferation marker, showed neither correlation with the presence of uptake nor the maximum standardized uptake value.

Gastrin promotes intestinal polyposis through cholecystokinin-B receptor-mediated proliferative signaling and fostering tumor microenvironment

Increased serum gastrin concentrations in patients with colorectal cancer suggested the tumorigenic trophic effect of gastrin. Detailed and global molecular mechanisms explaining trophic effect of gastrin had not been revealed. In the current study, intestinal polyposis of APC(Min/⁺) mice was compared between phosphate buffered saline (PBS) injected and gastrin (10 μg/kg, thrice per week) injected group. Total number of intestinal polyposis was counted and immunohistochemical staining with F4/80 and CD3 was done. MTT assay, cell cycle analysis, and Western blot for cyclin D1, CDK4, and β-catenin were performed in Raw 264.7 and HCT116 cells before and after gastrin administration. Experiments were repeated with YM022 or transfection with si-cholecystokinin-B receptor (CCK-B-R). Intraperitoneal gastrin significantly increased intestinal polyposis in APC(Min/⁺) mice (P<0.005), in which significant increases in macrophage were noted on F4/80 immunohistochemical staining (Plt;0.05) as well as Ki-67 staining (Plt;0.05) after gastrin. On comparative cytokine array, gastrin increased interleukin-1β (IL-1β), interleukin 3Rβ (IL-3Rβ), stromal cell-derived factor-1α (SDF-1α), thymus and activation-regulated chemokine (TARC), and thymus-derived chemotactic agent 3 (TCA-3) in macrophage cells, which was further confirmed with real time polymerase chain reaction (RT-PCR) analysis (P<0.05). In addition to increased inflammatory cytokines, gastrin increased macrophage proliferation accompanied with increased cyclin D1 and CDK4. Targeted for HCT116 cells, gastrin significantly increased proliferation as well as increases in synthetic phase of cell cycle. YM022 as gastrin antagonist significantly abolished the trophic actions of gastrin (P<0.05). HCT116 cells transfected with siCCK-B-R, gastrin did not increase either cell cycle or β-catenin in spite of gastrin administration. Conclusively, gastrin promoted intestinal polyposis through either direct gastrin receptor-mediated proliferative signaling or fostering tumor microenvironment such as macrophage activation.

HMGA1 induces intestinal polyposis in transgenic mice and drives tumor progression and stem cell properties in colon cancer cells

BACKGROUND

Although metastatic colon cancer is a leading cause of cancer death worldwide, the molecular mechanisms that enable colon cancer cells to metastasize remain unclear. Emerging evidence suggests that metastatic cells develop by usurping transcriptional networks from embryonic stem (ES) cells to facilitate an epithelial-mesenchymal transition (EMT), invasion, and metastatic progression. Previous studies identified HMGA1 as a key transcription factor enriched in ES cells, colon cancer, and other aggressive tumors, although its role in these settings is poorly understood.

METHODS/PRINCIPAL FINDINGS

To determine how HMGA1 functions in metastatic colon cancer, we manipulated HMGA1 expression in transgenic mice and colon cancer cells. We discovered that HMGA1 drives proliferative changes, aberrant crypt formation, and intestinal polyposis in transgenic mice. In colon cancer cell lines from poorly differentiated, metastatic tumors, knock-down of HMGA1 blocks anchorage-independent cell growth, migration, invasion, xenograft tumorigenesis and three-dimensional colonosphere formation. Inhibiting HMGA1 expression blocks tumorigenesis at limiting dilutions, consistent with depletion of tumor-initiator cells in the knock-down cells. Knock-down of HMGA1 also inhibits metastatic progression to the liver in vivo. In metastatic colon cancer cells, HMGA1 induces expression of Twist1, a gene involved in embryogenesis, EMT, and tumor progression, while HMGA1 represses E-cadherin, a gene that is down-regulated during EMT and metastatic progression. In addition, HMGA1 is among the most enriched genes in colon cancer compared to normal mucosa.

CONCLUSIONS

Our findings demonstrate for the first time that HMGA1 drives proliferative changes and polyp formation in the intestines of transgenic mice and induces metastatic progression and stem-like properties in colon cancer cells. These findings indicate that HMGA1 is a key regulator, both in metastatic progression and in the maintenance of a stem-like state. Our results also suggest that HMGA1 or downstream pathways could be rational therapeutic targets in metastatic, poorly differentiated colon cancer.

Intestinal tumorigenesis is not affected by progesterone signaling in rodent models

Clinical data suggest that progestins have chemopreventive properties in the development of colorectal cancer. We set out to examine a potential protective effect of progestins and progesterone signaling on colon cancer development. In normal and neoplastic intestinal tissue, we found that the progesterone receptor (PR) is not expressed. Expression was confined to sporadic mesenchymal cells. To analyze the influence of systemic progesterone receptor signaling, we crossed mice that lacked the progesterone receptor (PRKO) to the Apc^Min/+ mouse, a model for spontaneous intestinal polyposis. PRKO-Apc^Min/+mice exhibited no change in polyp number, size or localization compared to Apc^Min/+. To examine effects of progestins on the intestinal epithelium that are independent of the PR, we treated mice with MPA. We found no effects of either progesterone or MPA on gross intestinal morphology or epithelial proliferation. Also, in rats treated with MPA, injection with the carcinogen azoxymethane did not result in a difference in the number or size of aberrant crypt foci, a surrogate end-point for adenoma development. We conclude that expression of the progesterone receptor is limited to cells in the intestinal mesenchyme. We did not observe any effect of progesterone receptor signaling or of progestin treatment in rodent models of intestinal tumorigenesis.

Suppression of colon cancer metastasis by Aes through inhibition of Notch signaling

Metastasis is responsible for most cancer deaths. Here, we show that Aes (or Grg5) gene functions as an endogenous metastasis suppressor. Expression of Aes was decreased in liver metastases compared with primary colon tumors in both mice and humans. Aes inhibited Notch signaling by converting active Rbpj transcription complexes into repression complexes on insoluble nuclear matrix. In tumor cells, Notch signaling was triggered by ligands on adjoining blood vessels, and stimulated transendothelial migration. Genetic depletion of Aes in Apc(Δ716) intestinal polyposis mice caused marked tumor invasion and intravasation that were suppressed by Notch signaling inhibition. These results suggest that inhibition of Notch signaling can be a promising strategy for prevention and treatment of colon cancer metastasis.

Globular amyloid deposits isolated to the small bowel: a rare association with AL amyloidosis

We describe a 55-year-old man with isolated duodenal and jejunal amyloidosis producing rare endoscopic and histologic findings. The patient had no specific gastrointestinal complaints but underwent esophagogastroduodenoscopy and colonoscopy because of progressive microcytic anemia. Endoscopy revealed multiple polyps, some filiform and measuring up to 3 cm in length, in the duodenum and proximal jejunum. Microscopically, the polyps resulted from amyloid deposition, predominantly within the submucosa, but also focally involving muscularis mucosae and lamina propria. The amyloid formed multiple globular submucosal deposits with a lamellated appearance reminiscent of corpora amylacea; linear amyloid deposition was also present in a perivascular distribution and within the overlying mucosa. Immunophenotyping confirmed AL amyloidosis with lambda immunoglobulin light chain restriction. There was no clinical evidence of visceral amyloidosis. The source of lambda light chain production was unclear as bone marrow biopsy and multiple gastrointestinal biopsies revealed normal numbers of polyclonal plasma cells. Further, immunoglobulin-free light chain assay was normal, as were serum and urine protein electrophoreses with immunofixation. This endoscopic presentation of isolated small bowel polyposis is an uncommon association with AL amyloidosis and to our knowledge this represents the first case of globular gastrointestinal amyloidosis resulting from AL amyloid.

Distinct secreted Frizzled receptor protein 1 staining pattern in patients with hyperplastic polyposis coli syndrome

CONTEXT

Patients with hyperplastic polyposis coli syndrome are thought to harbor precursor lesions of a proposed hyperplasia-carcinoma pathway in colorectal cancer, but morphologic recognition of such lesions remains difficult. Hypermethylation of the secreted Frizzled receptor protein 1 gene on chromosome 8p12 is one of the earliest molecular alterations in colorectal carcinogenesis, potentially disrupting the Wnt signaling cascade of cellular growth control.

OBJECTIVE

To determine if hyperplastic polyps from patients with hyperplastic polyposis coli syndrome show a distinct immunohistochemical expression pattern for mismatch repair proteins and secreted Frizzled receptor protein 1 compared to their sporadic counterparts.

DESIGN

Immunohistochemical studies (secreted Frizzled receptor protein 1, 3 mismatch repair proteins, and p53) were performed on 23 hyperplastic polyps, 6 synchronous colon cancers, and normal colonic mucosa from 6 patients with hyperplastic polyposis coli syndrome and were compared with studies of sporadic hyperplastic polyps obtained from 13 matched control subjects.

RESULTS

The staining pattern for the mismatch repair proteins MLH-1, MSH-2, and MSH-6 did not differ between sporadic and syndromic hyperplastic polyps. In contrast, 52% of syndromic hyperplastic polyps showed a reproducible and distinct staining pattern for secreted Frizzled receptor protein 1 that was not seen in control specimens and that was associated with larger polyp size (P =.002) and location in the proximal colon (P =.01).

CONCLUSIONS

Some hyperplastic polyps from patients with hyperplastic polyposis coli syndrome show a secreted Frizzled receptor protein 1 immunophenotype that could indicate alterations of cellular growth control. These findings may help identify precursor lesions in the proposed hyperplasia-carcinoma pathway of colorectal carcinogenesis.

Gastrointestinal polyposis syndromes

Numerous polyposis syndromes involve the gastrointestinal (GI) tract, including both non-hereditary and hereditary types. Causative genes are now known for the seven major syndromes. Genetic and clinicopathologic features are reviewed here and cancer predisposition is emphasized. Genetic testing is available for the GI polyposis syndromes, and can be accessed through GeneTests-GeneClinics on the Internet at http://www.genetests.org/. The website is available at no cost and is a publicly funded medical genetics resource for health care providers and researchers.

De novo crypt formation and juvenile polyposis on BMP inhibition in mouse intestine

Little is known about the signaling mechanisms that determine the highly regular patterning of the intestinal epithelium into crypts and villi. With the use of mouse models, we show that bone morphogenetic protein (BMP)-4 expression occurs exclusively in the intravillus mesenchyme. Villus epithelial cells respond to the BMP signal. Inhibition of BMP signaling by transgenic expression of noggin results in the formation of numerous ectopic crypt units perpendicular to the crypt-villus axis. These changes phenocopy the intestinal histopathology of patients with the cancer predisposition syndrome juvenile polyposis (JP), including the frequent occurrence of intraepithelial neoplasia. Many JP cases are known to harbor mutations in BMP pathway genes. These data indicate that intestinal BMP signaling represses de novo crypt formation and polyp growth.