Eastern Canadian colorectal cancer consensus conference: application of new modalities of staging and treatment of gastrointestinal cancers.

The annual Eastern Canadian Colorectal Cancer Consensus Conference was held in Ottawa, Ontario, October 22-23, 2010. Health care professionals involved in the care of patients with colorectal cancer participated in presentation and discussion sessions for the purpose of developing the recommendations presented here. This consensus statement addresses current issues in the management of colorectal cancer, such as the use of epidermal growth factor inhibitors in metastatic colon cancer, the benefit of calcium and magnesium with oxaliplatin chemotherapy, the role of microsatellites in treatment decisions for stage II colon cancer, the staging and treatment of rectal cancer, and the management of colorectal and metastatic pancreatic cancers.

A single-centre chart review exploring the adjusted association between breast cancer phenotype and prognosis.

PURPOSE AND METHODS: Using a retrospective chart review, we investigated the differences in survival and prognostic factors between patients with triple-negative breast cancer (tnbc) and those with non-tnbc. The review included 1018 breast cancer patients who were diagnosed between 2000 and 2005 in Essex, Kent, and Lambton counties in Ontario, Canada. RESULTS: Our findings indicate that, although the unadjusted results suggested that patients with tnbc were more likely than patients with non-tnbc to die [hazard ratio (hr): 2.29; 95% confidence interval (ci): 1.33 to 2.93], an adjusted survival analysis revealed no significant difference in overall survival between the groups (hr: 1.22; 95% ci: 0.63 to 2.39). The significant predictors of survival in the adjusted analysis were age, stage of cancer, and size of cancer. CONCLUSIONS: Our findings support those of earlier reports, which suggest that presenting tumour size is the most important prognostic factor in tnbc. Investigations into unique screening methods to identify these tumours at an earlier stage and to prevent advanced-stage cancer in this patient subpopulation are necessary.

Human keratinocytes constitutively produce but do not process interleukin-18.

BACKGROUND: Interleukin (IL)-18 is a potent immunomodulatory cytokine which promotes T-helper (Th) 1 and cytotoxic responses. IL-18 signals through a two-chain receptor (IL-18R and accessory protein-like subunit, AcPL), and an inhibitory molecule, IL-18 binding protein (IL-18BP), has recently been characterized. OBJECTIVES: The aim of the present study was to define the production of IL-18 and its receptor by human keratinocytes. METHODS: The presence of IL-18 was determined using polymerase chain reaction in human keratinocyte cultures with or without treatment with potential inducers. RESULTS: The IL-18 gene was constitutively transcribed by primary human keratinocytes and cell lines and was not significantly altered following exposure to IL-1 beta, tumour necrosis factor-alpha, interferon (IFN)-gamma, phorbol myristate acetate or nickel sulphate. IL-18 protein was constitutively present at high levels in keratinocyte lysates and was detectable in supernatants exclusively in the unprocessed, 24-kDa form. Cytokine exposure failed to induce any change in protein levels or processing. Primary keratinocytes produced IL-18R and AcPL constitutively at the mRNA level, in addition to low levels of IL-18BP, which was transcriptionally inducible following treatment with IFN-gamma. CONCLUSIONS: These findings demonstrate that IL-18 is constitutively synthesized by human keratinocytes and is released in an unprocessed form in vitro. Release of IL-18 by human keratinocytes may permit them to regulate IFN-gamma production during cutaneous inflammatory responses and suggests that IL-18 may represent an attractive target for immunomodulatory intervention in Th1-mediated inflammatory diseases such as psoriasis.

Keratin 15 expression in stratified epithelia: downregulation in activated keratinocytes.

Keratin 15 (K15) is a type I keratin without a defined type II partner whose expression in epidermal diseases has not been investigated. In this study we have used LHK15, a monoclonal antibody raised against the last 17 amino acids of the K15 polypeptide, to show that K15 is expressed primarily in the basal keratinocytes of stratified tissues, including the fetal epidermis and fetal nail. Although K15 in normal hair follicles was virtually absent from hair bulbs, it was expressed by a subset of keratinocytes in the outer root sheath. By comparison, K14 expression was found throughout the outer root sheath of hair follicles; however, when both K14 alleles were naturally ablated, the expression of K15 was also observed throughout the outer root sheath of the follicles. Expression of K15 mRNA was assessed by in situ hybridization and corroborated the data from immunostaining. An increase in K15 mRNA and protein expression in hair follicles from the K14 ablated epidermis suggested an upregulation of the K15 gene in the absence of the K14 protein. In organotypical cultures where differentiating keratinocytes expressed markers of activated phenotype, i.e., K6 and K16, expression of K15 was undetectable. The expression of K15 mRNA and protein was also downregulated in two hyperproliferating situations, psoriasis and hypertrophic scars. Because keratinocytes in psoriasis and hypertrophic scars are activated, we conclude that K15 expression is not compatible with keratinocyte activation and the K15 gene is downregulated to maintain the activated phenotype.

Isolation, sequence and expression of the gene encoding human keratin 13.

Keratins are a family of highly homologous proteins expressed as pairs of acidic and basic forms which make intermediate filaments in epithelial cells. Keratin 13 (K13) is the major acidic keratin, which together with K4, its basic partner, is expressed in the suprabasal layers of non-cornified stratified epithelia. The mechanism which allows mucosal-specific expression of this keratin remains unknown. To provide insight into the tissue-specific expression, we have isolated the human K13 gene by screening a chromosome 17 library with a specific K13 cRNA probe. Sequence analysis of unidirectional deletions produced by transposon Tn3 has revealed that the gene is 4601 nucleotides long and contains seven introns and eight exons. When driven by the CMV promoter, the gene produced K13 protein in MCF-7 cells, which normally do not express this protein. Two transcription-start sites were identified, the major being at 61 and the minor at 63 nucleotides upstream of ATG. The upstream sequence contained a TATA box and several other putative transcription factor binding sites. A single copy of the K13 gene was detected in the human genome by Southern hybridisation and polymerase chain reaction. K13 mRNA shows differential expression in cultured keratinocytes, and in A431 cells the RNA levels remained independent of calcium concentrations in the culture medium. Characterisation of the human K13 gene will facilitate elucidation of the molecular mechanism regulating K13 expression in mucosal tissues.

Macrophages during fibrosis following scleral fistulising surgery in a rat model.

PURPOSE: Glaucoma filtration surgery can fail in a minority of patients as a result of fibrosis in the subconjunctival bleb space and closure of the scleral fistula. In this study, the rat eye has been used as an experimental model for fistulising surgery in order to evaluate the clinical manifestation of bleb failure with the morphological events of the wound healing process. METHODS: A conjunctival bleb was successfully formed in 25 rats and was examined daily using slit lamp microscopy to evaluate postoperative inflammation and the presence of a bleb. At defined post-operative time points, serial frozen sections of eyes were stained immunohistochemically using a panel of monoclonal antibodies directed against known surface markers on rat immune/inflammatory cells. Positively stained cells were counted (a) in the bleb site, (b) at the sclerostomy and (c) at the suture site. RESULTS: Following an initial post-operative inflammation, a surgically formed sclerostomy and conjunctival bleb underwent a granulation and scarring response so that by 7-19 days the bleb had disappeared. Using the monoclonal antibodies applied in this study, it was possible to show that macrophages most likely play a major and pivotal role throughout the sequence of events that lead to repair of the fistula and closure of the bleb. It was also noted that the presence of an otherwise inert nylon suture used to close the incised conjunctiva can serve as a focus for macrophages. CONCLUSION: The rat has been successfully used as an experimental model of fistulising surgery and its subsequent failure. The use of a panel of monoclonal antibodies directed against specific surface markers on immune-inflammatory cells, highlighted macrophages to be prominent in all stages of this wound healing process.

The humoral response to an allograft.

Antibodies are known to damage grafted tissues by a variety of means, so it is important to know how the humoral response is initiated. In this paper we summarise the cellular events in B cell activation, the mechanisms of antibody-mediated rejection and the evidence that antibody apparently does not contribute to early corneal graft rejection. The role of antibodies in chronic graft loss is discussed.

Prolongation of rat corneal graft survival by treatment with anti-CD4 monoclonal antibody.

A rat model of orthotopic corneal graft rejection was used to investigate the effect of depletion of subpopulations of immune cells by treatment with monoclonal antibodies. Though CD4+ cells were not eliminated completely by anti-CD4 monoclonal antibodies there was a profound delay in the rejection times of orthotopic corneal allografts. Furthermore a third of the CD4+ depleted animals failed to reject corneal allografts by 100 days post grafting. Despite an almost complete depletion of circulating CD8+ cells, the anti-CD8 antibody treated animals rejected corneal allografts in a similar time course to allografted controls treated with a non-reactive control antibody OX21. These results demonstrate that CD8+ T-cells are not required for rejection of corneal allografts whereas CD4+ T-cells play a critical role in the rejection response. Treatment with anti-CD4 antibodies may have a useful clinical application.