Identification of mutations in the mismatch repair genes of hereditary non-polyposis colorectal cancer (HNPCC) families can lead to improved management and screening of affected family members. This study aimed to characterise the mutation profile of MLH1 and MSH2 in a South African colorectal cancer cohort. Twenty patient samples were screened for mutations in MLH1 and MSH2 using Sanger sequencing and Multiplex Ligation-dependent Probe Amplification (MLPA). Three previously reported pathogenic mutations were found using Sanger sequencing, two in MLH1 (c.454-13A>G and c.731_734delGTTA) and one in MSH2 (c.2006-6T>C). Six novel variants were detected using Sanger sequencing, two in MLH1 and four in MSH2. Further investigation of the novel variants strongly suggests that one variant in MLH1 (c.885-1G>A) is pathogenic and two have an unknown contribution towards disease. Molecular diagnostic screening of mutations in MLH1 and MSH2 has the potential to improve surveillance and management of HNPCC in South Africa.

Epithelial cancers such as colorectal cancers are highly predominant in the Southern African population, and are attributable to a number of factors, including genomic instability due to histone modifications and aberrant DNA methylation of gene promoters, as well as the inactivation of tumour-suppressor genes or the activation of oncogene pathways. The Wnt/β-catenin pathway plays a vital role in the regulation of intestinal epithelial cells, and is aberrantly activated in colon neoplasms. Krüppel-like factor 4 (KLF4) is a tumour suppressor gene that is hypermethylated at its promoter region and therefore down-regulated in colon cancer cells. This zinc finger transcription factor is crucial in colon cancer cells, where its induction has been proposed to regulate tumourigenesis. Over recent years, epigenetic modulators such as histone deacetylase (HDAC) inhibitors and DNA methyltransferase (DNMT) inhibitors have been investigated with regards to their potential anticancer activities. The following study assessed the in vitro effects of the HDAC inhibitor Valproic acid and DNMT inhibitor Zebularine on the expression of KLF4 in early (SW480) and late stage (DLD-1) colon cancer, and breast (MCF-7) cancer cells. At the onset, bioinformatics tools were utilised to predict and assess the methylation status and to examine methylation patterns within the KLF4 and CTNNB1 (β-catenin) genes. In association with this, methylated DNA within early and late stage colon cancer cells was quantified. Here, the 5’ untranslated region of KLF4 was highly methylated, while CTNNB1 displayed a low frequency of methylation. Following drug treatments, with Valproic acid and Zebularine respectively, gene expression profiles showed that high dosages increased the expression of KLF4 relative to low doses in early stage cancer cells; however the greatest induction of KLF4 was observed in late stage cancer cells in response to a high dose combination treatment with Valproic acid and Zebularine. CTNNB1 was antagonistically regulated relative to KLF4, wherein its expression was down-regulated post-treatment. Breast cancer cells surprisingly exhibited opposing results, with both KLF4 and CTNNB1 being up-regulated following high dose treatments, and the low dose treatments displaying the greatest anti-tumourigenic activities. Confocal microscopy results illustrated that KLF4 was localised in the nucleus and nuclear periphery, where it could associate directly with β-catenin. Thus in response to epigenetic therapy, KLF4 was differentially expressed in early and late stage colon cancer cells as a tumour suppressor. The down-regulation of β-catenin in colon cancer cells resulted in the suppression of the Wnt signalling pathway, thereby exerting anti-tumourigenic and anti-proliferative properties on the cells. Therefore, this study concludes that Valproic acid and Zebularine may serve as potential anti-cancer agents in the pursuit of an epigeneic therapy for colorectal cancer.

Diss. (sammanfattning) Uppsala : Univ., 2001. / Härtill 5 uppsatser.

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2005. / Härtill 4 uppsatser.

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 67-74).

Thesis (Ph. D.)--University of Washington, 2002. / Vita. Includes bibliographical references (leaves 133-160).

Diss. (sammanfattning) Umeå : Univ., 2005. / Härtill 5 uppsatser.

a variety of South African Hospitals: a retrospective study Purpose: To examine the number of lymph nodes present in specimens submitted for histological examination from a variety of South African hospitals; the identification of factors that influence nodal yield and node positivity; determining whether oncological clearance is improved based on the number of nodes examined in high volume centers versus low volume centres; the establishment of guidelines on where surgery for colorectal cancer should ideally be performed. Patients and methods: Pathology reports of resected specimens of colorectal adenocarcinoma in the database of the National Health Laboratory Service Johannesburg laboratory from 2000 to 2005, were examined for patient demographics, referring hospital, tumour specific features of T-stage, degree of differentiation, lymphovascular invasion and adenocarcinoma subtype (mucinous versus non-mucinous), number of lymph nodes identified, number of nodes positive and whether preoperative radiotherapy was administered. Hospitals were grouped into four groups of Charlotte Maxeke Johannesburg Academic Hospital, Helen Joseph Hospital, private hospitals and non-academic public hospitals. Patients were grouped according to the number of lymph nodes retrieved into the following groups: not recorded, no nodes identified,1-7 nodes identified, 8-12 nodes, 13-18 nodes, and greater than 18 nodes identified. Additionally, patients were subdivided into those with nodal metastasis and those without, and into colon and rectal cancer respectively. Multivariate analysis was performed via StatSoft, Inc. (2008) STATISTICA (data analysis software system), version 8.0 on the different lymph node groups versus the abovementioned covariates. Results: Of the 365 patients identified, the mean number of lymph nodes examined per resected specimen was 8.9 (±6.2SD), with significant differences noted between the different resection subtypes (p < 0.001). No statistically significant difference in mean number of nodes identified could be seen between the various hospitals. Alarmingly, in the group of patients where no metastatic nodes could be identified, the recommendation of 12 or more nodes examined per specimen was upheld in only 29% of cases. Factors associated with positive lymph nodes in this study include T-stage, degree of differentiation and lymphovascular invasion by the tumour. No significant benefit in terms of finding metastasis nodes could be demonstrated by examining more than 18 nodes. Conclusions and recommendations: This study highlights a substandard nodal assessment in colorectal cancer specimens overall, including the academic hospitals. More than 70% of node negative patients in this series may have been understaged. Close liaison between the surgeon and examining pathologist is recommended. In the presence of the identified high risk factors for nodal involvement and a substandard nodal assessment, additional measures i.e. fat clearance and immunohistochemistry need employment. A prospective study assessing quality of surgery is necessary, as is the creation of a central database to improve overall quality of cancer care.

Introduction: At the core of UK policy for improving outcomes in cancer are goals for a healthcare where patients are empowered through information enabling engagement in shared care decisions with clinicians. Interventions to support patients’ engagement in shared decision making are lacking within colorectal cancer and high grade glioma care despite intensive treatment regimens with uncertain outcomes. Navigation, a communication and decision support intervention, has been successfully piloted with prostate and breast cancer patients who demonstrated significantly more confidence and less uncertainty in their treatment decisions. With healthcare policy advocating patients be educated and engaged in their care, the applicability of this intervention to other cancer settings is required. The Navigation intervention includes: consultation planning with a Navigator, formulation of a consultation plan and recording (summary and CD) of the medical consultation. Objectives: To determine the effectiveness of the Navigation intervention in enhancing decision-making quality over time when compared with usual care, in patients with colorectal cancer. To explore repeated experiences of the Navigation intervention from the perspective of colorectal cancer (CRC) patients, patients with high grade glioma (HGG), and consulting clinicians. Design and Studies: A mixed methods study using a pragmatic randomised controlled trial and qualitative evaluation was undertaken during November 2010 – December 2013. The intervention was trialled separately with two cohorts of cancer patients (CRC and HGG). A longitudinal parallel-group pragmatic randomised controlled trial was conducted. Study 1 consisted of a longitudinal parallel-group pragmatic randomised control trial. Participants with colorectal cancer were openly randomised after completion of baseline measures to receive the intervention or usual care (no intervention). The intervention was administered to patients at three particular time points during first line cancer treatment. Participants completed tools collecting primary outcome (decision self-efficacy) and secondary outcomes (decision conflict, decision regret, anxiety and depression) measured prior to baseline, post consultation and at follow-up. Mean change in scores overtime and between groups were compared using Mixed ANOVAS. Study two was a prospective qualitative study undertaking serial in-depth semi-structured evaluation interviews with patients with High Grade Glioma. Study three undertook interviews with the consulting HGG and CRC clinicians. Framework analysis was undertaken. Setting: Two oncology settings within a tertiary cancer centre in Scotland. Participants: 132 patients with colorectal cancer (65 intervention, 67 control) participated in the randomised controlled trial. For the qualitative study, 17 colorectal trial participants (8 intervention, 9 control), 11 high grade glioma patients and 7 clinicians were interviewed. Evaluation Results: No significant difference was found between the control and Navigation intervention participants over time in the primary outcome of decision self-efficacy, or in the following secondary outcomes; decision conflict or anxiety and depression scores. At follow-up, the intervention group reported significantly less decision regret than the controls (p=0.039). In the qualitative data, Navigated participants reported being well prepared for medical consultations, able to actively engage in information exchange during consultation and enabled to recall and understand information provided. This was in contrast to participants receiving usual care who described being less prepared for medical consultations and experienced barriers to gathering information, such as time pressures, forgetting questions, and gaps in understanding. Clinicians identified that patients benefitted from preparing for, and having a written summary of, the consultation. Whereas neuro-oncology clinicians were supportive of Navigation as a tool to tailor information to patients; colorectal clinicians felt Navigation was a disruption to their normal consultation routine. Concern was expressed regarding the extra resource required by Navigated patients and therefore about the feasibility and sustainability of the intervention. Conclusions: Whilst models of shared decision making remain highly profiled in cancer strategies, information exchange and use of interventions in context is problematic. This evaluation of Navigation has demonstrated more impact on the process of decision making, rather than outcome per se, and has raised questions about its sustainability in clinical practice. A more nuanced understanding of different cancer pathways and the specific decisions to be made, may inform a more targeted use of decision support in cancer care.

Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 4 uppsatser.