Diarrhoea Caused by Diffuse Metastatic Lobular Breast Cancer.

A 70-year-old woman with a history of lobular breast cancer presented to our Outpatient Clinic with diarrhoea for the past 3 years. Clinical examination and laboratory research were normal. Colonoscopy showed diffuse mild erythema and a decreased vascular pattern. Biopsies from the ascending colon, transverse colon, and descending colon showed metastases of lobular breast carcinoma. Although gastrointestinal metastases are rare in breast cancer, our case emphasizes the need for further diagnostic efforts in patients with gastrointestinal symptoms and a history of breast carcinoma.

Hepatosplenic T-Cell Lymphoma: A Population-Based Study Assessing Incidence and Association With Immune-Mediated Disease.

Hepatosplenic T-cell lymphoma (HSTCL) is a rare malignancy of unknown incidence that has been associated with immune-mediated disease. This study explored the incidence and patient characteristics of HSTCL in a population of 15.5 million over a 13-year period using a comprehensive national pathology database in The Netherlands (Pathologisch-Anatomisch Landelijk Geautomatiseerd Archief) with 100% capture. Twelve cases of HSTCL were identified during this period. The overall incidence of HSTCL in the Dutch population over this period was estimated at 0.06 per million inhabitant-years. All but 2 of the patients were adults at the time of diagnosis (median age, 34.5 years), and most patients died within a year of diagnosis. Three patients had a history of immune-mediated disease, 1 of whom was receiving azathioprine at the time of HSTCL diagnosis. Azathioprine as well as anti-tumor necrosis factor-α agents have been reported as possibly being associated with HSTCL. None of the 12 HSTCL patients had been treated with an anti-tumor necrosis factor-α agent.

GFAP-Cre-mediated transgenic activation of Bmi1 results in pituitary tumors.

Bmi1 is a member of the polycomb repressive complex 1 and plays different roles during embryonic development, depending on the developmental context. Bmi1 over expression is observed in many types of cancer, including tumors of astroglial and neural origin. Although genetic depletion of Bmi1 has been described to result in tumor inhibitory effects partly through INK4A/Arf mediated senescence and apoptosis and also through INK4A/Arf independent effects, it has not been proven that Bmi1 can be causally involved in the formation of these tumors. To see whether this is the case, we developed two conditional Bmi1 transgenic models that were crossed with GFAP-Cre mice to activate transgenic expression in neural and glial lineages. We show here that these mice generate intermediate and anterior lobe pituitary tumors that are positive for ACTH and beta-endorphin. Combined transgenic expression of Bmi1 together with conditional loss of Rb resulted in pituitary tumors but was insufficient to induce medulloblastoma therefore indicating that the oncogenic function of Bmi1 depends on regulation of p16(INK4A)/Rb rather than on regulation of p19(ARF)/p53. Human pituitary adenomas show Bmi1 overexpression in over 50% of the cases, which indicates that Bmi1 could be causally involved in formation of these tumors similarly as in our mouse model.

DNA array analysis of the effects of aspirin on colon cancer cells: involvement of Rac1.

Aspirin and other non-steroidal anti-inflammatory drugs show efficacy in the prevention of colon cancer. The mechanism by which they do this is unclear. We used a commercially available DNA microarray to study changes in gene expression in 1176 cancer related genes in the HT29 colon cancer cell line induced by aspirin. Overall we find more genes that are significantly induced than are repressed. The pattern of gene expression changes is different at high concentrations of aspirin (5 mM) than at lower levels (500 and 50 microM). Genes involved in DNA damage signaling, nucleotide metabolism and the stress response are induced, and cell cycle related genes repressed. The small GTPase Rac1 is highly induced and this was confirmed by immunoblotting. We show using immunohistochemistry that Rac1 is expressed in mature colonocytes at the intercrypt table in human and mouse colon tissue. These results support the previous findings that aspirin has different actions at high concentrations than at low concentrations and further show the use of DNA array technology in the investigation of drug mechanisms of action. Furthermore, they point towards a role for Rac1 in the action of aspirin in colon cancer.

Activation of the canonical beta-catenin pathway by histamine.

Histamine signaling is a principal regulator in a variety of pathophysiological processes including inflammation, gastric acid secretion, neurotransmission, and tumor growth. We report that histamine stimulation causes transactivation of a T cell factor/beta-catenin-responsive construct in HeLa cells and in the SW-480 colon cell line, whereas histamine did not effect transactivation of a construct containing the mutated response construct FOP. On the protein level, histamine treatment increases phosphorylation of glycogen synthase kinase 3-beta in HeLa cells, murine macrophages, and DLD-1, HT-29, and SW-480 colon cell lines. Furthermore, histamine also decreases the phosphorylated beta-catenin content in HeLa cells and murine macrophages. Finally, pharmacological inhibitors of the histamine H1 receptor counteracted histamine-induced T cell factor/beta-catenin-responsive construct transactivation and the dephosphorylation of beta-catenin in HeLa cells and in macrophages. We conclude that the canonical beta-catenin pathway acts downstream of the histamine receptor H1 in a variety of cell types. The observation that inflammatory molecules, like histamine, activate the beta-catenin pathway may provide a molecular explanation for a possible link between inflammation and cancer.