Browsing by Author "Govender, Dhiren"
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- ItemOpen AccessBiomarker identification in HIV and non-HIV related lymphomas(2016) Magangane, Pumza Samantha; Naidoo, Richard; Govender, DhirenDLBCL is the most common lymphoma subtype occurring in older populations as well as in younger HIV infected patients. The current treatment options for DLBCL are effective for most patients yet the relapse rate is high. While many biomarkers for DLBCL exist, they are not in clinical use due to low sensitivity and specificity. In addition, these biomarkers have not been studied in the HIV context. Therefore, the identification of new biomarkers for HIV negative and HIV positive DLBCL, may lead to a better understanding of the disease pathology and better therapeutic design. Initially differences in the clinicopathological features between HIV negative and HIV positive DLBCL patients were determined by conducting a retrospective study of patients treated at GSH. Subsequent to this, potential protein biomarkers for DLBCL were determined using MALDI imaging mass spectrometry (IMS) and characterised using LCMS. The expression of one of the biomarkers, heat shock protein (Hsp) 70, was confirmed on a separate cohort of samples using immunohistochemistry. Our results indicate that the clinicopathological features for HIV negative and HIV positive DLBCL are similar except for median age, and frequency of elevated LDH levels. Several clinicopathological factors were prognostic for all DLBCL cases including age, gender, stage and bone marrow involvement. In addition, tumour extranodal site was also a prognostic indicator for the HIV negative cohort. The biomarkers identified in the study consisted of four protein clusters including glycolytic enzymes, ribosomal proteins, histones and collagen. These proteins could differentiate between control and tumour tissue, and the DLBCL subtypes in both cohorts. The majority (41/52) of samples in the confirmation cohort were negative for Hsp70 expression. The HIV positive DLBCL cases had a higher percentage of cases expressing Hsp70 than their HIV negative counterparts. The non-GC subtype also frequently overexpressed Hsp70, confirming MALDI IMS data. Expression of Hsp70 correlated with poor outcome in the HIV negative cohort. In conclusion, this study identified potential biomarkers for HIV negative and HIV positive DLBCL from both clinical and molecular sources. These may be used as diagnostic and prognostic markers complementary to current clinical management for DLBCL.
- ItemOpen AccessDetection of human papillomavirus (HPV) and expression of cell-cycle markers in breast carcinoma in a cohort of South African patients(2013) Fenwick, Sharon; Govender, DhirenBreast carcinoma is a common cancer in South African women. In the Republic of South Africa, 41 new cases of breast cancer are diagnosed per 100 000 population and the mortality rate is 21 per 100 000 population. Many risk factors have been implicated in the carcinogenesis of this disease; including smoking, family history and hormones, however, this only accounts for about 1/3 of the cases diagnosed. Some studies have implicated Human papillomavirus (HPV) as a possible aetiologic agent in the pathogenesis of breast carcinoma however the results have been inconsistent and sometimes controversial. This study was designed to determine the presence of HPV in breast cancer in a South African cohort and to investigate its influence on the cell cycle. A retrospective and prospective cell block study was undertaken.
- ItemOpen AccessEvaluation of the P13K pathway and downstream effect in Her-2 positive and negative breast carcinomas(2014) Rademan, Anina; Govender, DhirenBreast cancer management continues to be a challenge due to the heterogeneity of the disease and the fact that individuals with the same stage and pathological diagnosis may respond differently to treatment as a result of differences in gene expression. Several components of the Her-2/PI3K/Akt pathway were evaluated for their relevance as potential prognostic markers or indicators for treatment. A secondary objective was to evaluate the CISH technique for its suitability for analysis of Her-2 gene amplification on archived, Papanicolaou-stained fine needle aspiration (FNA) samples. Tissue blocks from a retrospective series of 93 primary breast carcinoma cases were selected, based on their Her-2 status. Twenty six of these cases received trastuzumab treatment while 67 did not. Expression of Her-2, ER, PI3K, PTEN, p-Akt, BCL2, NFĂŽÂşB, MDM2 and p53 were analysed and compared with various clinicopathological features. The CISH technique was evaluated for its suitability for analysis of Her-2 gene amplification on archived, Papanicolaou-stained FNA samples.
- ItemOpen AccessExpression levels of miRNA-127 in a cohort of HIV-positive and HIV-negative Diffuse Large B-Cell Lymphoma.(2018) Olivier, Chera; Naidoo, Richard; Govender, DhirenDiffuse Large B Cell Lymphoma is one of the most common Non-Hodgkin’s Lymphomas. It is prevalent in older age patients but as of late there has been a rise in the younger population in South Africa due to the rise of HIV. DLBCL is quite an aggressive cancer but can be treated, however the relapse rate is high. There are prognostic indicators which can be seen as factors which can be indicative of a poor outcome for patients. Micro-RNA(miRNA) are small non-coding RNA which can remain stable to be tested. There are several miRNAs which may be linked to prognosis, including miRNA-21 whose upregulated expression has been associated with bad prognosis. However, this is not specific to DLBCL and some studies done have indicated that there may be other miRNAs which are better suited to be biomarkers for DLBCL. Studies have pointed to the direction of miRNA127 as a more reliable microRNA in its association with prognosis in breast, cervical and gastric cancer as well as DLBCL. Objective: The primary aim of this study was to determine the association between miRNA127 and prognostic markers including immunohistochemical stains, survival status and the IPI factor to determine its significance as a prognostic indicator. An additional aim was to determine the correlation between HIV status and expression level of miRNA-127. Design: A total of 42 DLBCL cases were collected from the archive of Division of Anatomical Pathology, University of Cape Town/NHLS Groote Schuur. The H&E slides were assessed before RNA was extracted from FFPE tissue and converted to cDNA. Real time quantitative RT-qPCR was used to assess the expression of the microRNA. Normal tissue as well as reactive lymph node tissue were used as controls. The expression patterns were also correlated to the clinical information to determine if there was any relationship. Results: Out of the 42 cases used, 10 cases were silenced, and 31 cases had high miRNA-127 expression. The expression levels were correlated with the IPI factors and the other clinicopathologic features however no significant conclusion were determined. Conclusion: We found high expression of miRNA-127 cases in the majority of the DLBCL cases. There was no correlation between HIV status and the expression of miRNA-127, nor between the expression and any of the clinicopathological feature. For future studies it is advised that more equally distribution of samples (both HIV status and gender) are obtained, this will allow for a better comparative study.
- ItemOpen AccessThe histopathology and immunohistochemical expression of cell cycle regulators and mismatch repair gene proteins in colorectal carcinoma : a comparative study(2015) Sookhayi, Raveendra; Govender, DhirenIntroduction: It has been reported that HNPCC colorectal carcinomas demonstrate a better prognosis compared to sporadic carcinoma, however the exact mechanism for this is still uncertain. It is possible that tumour morphology, location and cell cycle markers may be indicators of the underlying molecular mechanism. In a resource limited setting these factors may help to stratify which cases need further molecular testing and genetic counselling. Aims and objectives: To characterise the macroscopic and microscopic pathology in three cohorts of patients. The cohorts include (1) patients with CRCs that are < 50 years and mutation negative, (2) < 50 years and DNA mismatch repair gene mutation positive and (3) more than 50 years (sporadic). To investigate the immunoexpression of the cell cycle regulators (p21, p27, p53, c-myc, cyclin D1 and cyclin E) and MMP-7 in each cohort. To compare the immunoexpression of each marker between cohort s. To correlate the immunoexpression of each marker with tumour type, stage and grade. Materials and methods: In total, 17 mutation negative, 15 mutation positive and 28 sporadic adenocarcinoma resection cases were available for study. The histopathological features of all cases were reviewed. The cases were stained with antibodies against p21, p27, cyclin D1, cyclin E, p53, c- myc MMP -7, MLH1, MSH2 and MSH6. Results were considered statistically significant if P < 0.05, and P <0.017 if 3 pairs of medians were compared. Results: The mutation positive tumours were more frequently right sided tumours and showed mucinous differentiation, tumour infiltrating lymphocytes and an expanding border. The sporadic and mutation negative cohort s showed similar morphology. In the sporadic cohort, the five tumours that were MLH1 negative demonstrated morphological features of MSI-H tumours. MLH1 mutations were the commonest. MLH1 immuno expression was lost in the mutation positive tumours and was statistically significant when compared to the other two cohorts. There was no statistical significance among the three cohorts for MSH2 and MSH6 immunoexpression. There was no statistically significant difference in immunoexpression for p21, p27, p53 and MMP-7 among the three cohorts. Furthermore, there was no association with tumour type and stage. Cyclin D1 expression was increased in the mutation positive cohort and was statistically significant when compared to the mutation negative cohort only. Cyclin E expression was also increased in the mutation positive cohort and was statistically significant when compared to the sporadic cohort only. Conclusion: The morphological features of colorectal carcinomas can be helpful in identifying MS I-H tumours and cases requiring further molecular studies. The cell cycle marker expression s did not explain the expected differences in patient outcome and prognosis. The mutation negative cohort in our population continues to remain enigmatic and further testing at the molecular level is required, that may reveal another novel pathway of colorectal carcinogenesis or other novel mutations in mismatch repair genes.
- ItemOpen AccessInteraction between DC-SIGN and DC-SIGNR with HHV-8 (LANA-1) and HIV-p24 in Castleman disease(2018) Chetty, Dharshnee Rama; Govender, DhirenBackground: Castleman disease (CD) is a lymphoproliferative disorder with four subtypes, some of which are aetiologically linked to Human Herpes virus 8 (HHV-8) which is known to cause diseases preferentially occurring in HIV-infected individuals. There has been a notable increase in the number of patients with HIV/HHV-8 associated CD diagnosed in the Groote Schuur hospital complex. Aims: The aim of the study was to determine the role of DC-SIGN, DC-SIGNR, p24 and HHV-8 (LANA-1) in Castleman disease. Our objectives were to identify the presence of DC-SIGN and DC-SIGNR in HHV-8 infected cells, determine whether HHV-8 and p24 (HIV) co-infection occurs in the same cells and to determine whether HHV-8 infects B and/or T cells. This study not only represents the largest and first immunophenotypic investigative evaluation of CD but also signifies the first double staining immunohistochemical analysis of CD diagnosed at Groote Schuur hospital. Methods: This was both a retrospective descriptive as well as an analytic cross-sectional immunohistochemistry study. Fifty cases of CD diagnosed at the Division of Anatomical Pathology, National Health Laboratory Service, Groote Schuur hospital over a ten and half year period were included in the study. Double immunohistochemistry was used to characterise HHV-8 infected cells using LANA-1 antibody, in conjunction with DC-SIGN, DC-SIGNR, p24, CD20 and CD3. Immunophenotypic analysis was then performed to assess 1) the number of infected HHV-8 cells and 2) number and distribution of cells co-expressing HHV-8 and DC-SIGN, DC-SIGNR, p24, CD20 and CD3. The immunophenotypic profiles were then compared to the CD morphologic subtypes. Results: The study cohort included 26 male and 24 female patients (M: F = 1.08:1), mean age 37.7 years. There were 16 hyaline vascular CD (HV-CD), 16 plasmablastic CD (Pb-CD). Nine plasma cell CD and 9 mixed-CD subtypes. There was a statistically significant association between HIV (n=45) and HHV-8 (n=40) positivity (p < 0.0002). CD4 counts and HAART enrolment were not predictive of CD development (p = 0.6120). Concurrent Kaposi sarcoma was seen in 16% (n=8) of the cohort. When comparing Pb-CD and HV-CD, there were statistically significant differences in density of LANA-1 infected cells (p<0.0002), LANA-1/DC-SIGN co-expressing cells (p <0.0072) and LANA-1/p24 co-expressing cells (p<0.0001). Conclusions: The findings of this study suggest that DC-SIGN may have a role in HHV-8 entry into cells. Furthermore, there is evidence that HIV and HHV-8 co-infection may function synergistically in CD. It is possible that DC-SIGN and DC-SIGNR facilitate dual viral entry into cells and influence viral replication and persistent infection.
- ItemOpen AccessInvestigation of microRNA expression in thyroid carcinoma among South Africa patients(2017) Mokhesi, Neo; Naidoo, Richard; Govender, Dhiren; Ross, Ian L; Dandara, ColletObjective: Thyroid cancer affects approximately 298 million people worldwide and the major challenge is reliably distinguishing patients who present with poor prognosis from those who do not. There are genetic markers that have been shown to be associated with poor clinical outcome in thyroid cancer, which include mutations in the BRAF and RAS genes. In addition to genetic variation, recent studies have reported on the effects of micro-ribonucleic acids' (miRNAs) differential expression observed in tumour and normal tissue as another possible marker of thyroid cancer prognosis. Therefore, miRNA expression signatures in thyroid cancer could be used as biomarkers for prognosis and diagnosis. This study compared the expression of miRNAs in papillary thyroid cancer and follicular thyroid cancer. Methods: As part of a preliminary study, 66 differentiated thyroid cancer samples were obtained from patients attending Groote Schuur Hospital and used in the study. MiRNA miScript polymerase chain reaction (PCR) Array (Qiagen) was used to determine the differential miRNA expression profiles between follicular thyroid carcinoma (FTC) and papillary thyroid carcinoma (PTC). Real time PCR was employed to confirm the expression levels of miRNA- 21 and miRNA-122. Results: 17 miRNAs were upregulated in PTC and 14 in FTC. There were significant differences in the miRNA expression between FTC and PTC. For example, miRNA-21 was the most upregulated miRNA in PTC and miRNA-122 in FTC. We found no correlation of the expression of these miRNAs to clinicopathological features. We observed an association of BRAF mutation positivity to advanced tumour stage and advanced age of presentation however, no correlation was seen to miRNA-21 or miRNA-122 expression. Conclusion: Although we did not observe correlations between miRNAs and any of the clinicopathological features, microRNA expression profile signatures were able to differentiate between PTC and FTC and could potentially be further validated as diagnostic markers.
- ItemOpen AccessA study to investigate the role of P27 and Cyclin E immunoexpression as a prognostic factor in early breast carcinoma(2006) Pillay, Komala; Govender, DhirenCyclin E and p27 expression is easy to assess in human tissues by standard immunohistochemical techniques. Immunohistochemistry is cost effective, relatively easy to perform and will play more of a role in the future management of cancer. To investigate the role of p27 and cyclin E immunoexpression as a prognostic factor in early breast carcinoma. Cyclin E and p27 immunohistochemistry was performed on sixty six cases of breast carcinoma submtted over a five year period to the Division of Anatomical Pathology, Groote Schuur hospital; Whittaker and Associates; and PathCare. All tumours included in this study were less than 5cm in diameter (pT1 and pT2 stage) and all the patients had wide local excisions peformed. Follow up information was obtained from patient folders in the Department of Radiation Oncology.
- ItemOpen AccessTuberculous anal fistulas-prevalence and clinical features in an endemic area(Health and Medical Publishing Group, 2009) Stupart, Douglas; Goldberg, Paul; Levy, Anthony; Govender, DhirenIntroduction: The aim of this study was to determine the prevalence of tuberculosis (TB) in anal fistulas at a referral hospital in Cape Town, and to document the clinical features and course of patients with tuberculous anal fistulas. Patients and methods: This was a prospective study of all patients who underwent surgery for anal fistulas at the Colorectal Surgery Unit at Groote Schuur Hospital, Cape Town, from 2004 to 2006. Tissue was submitted for histopathological examination, Ziehl-Neelsen (ZN) staining and TB culture. The patients with proven TB were followed up until January 2008. Results: During the 3-year study period, 117 operations were performed on 96 patients. TB was diagnosed in 7 of the 96 patients (7.3%). In 5 of these 7 cases, the diagnosis of TB could be proven on histological examination and ZN staining, while in 2 cases the diagnosis could only be made on TB culture. None of the 7 patients had systemic features suggestive of TB, and only 1 had evidence of TB on a chest radiograph. Five patients were HIV-negative, and 2 declined testing. After a median follow-up of 2 years, 5 of 7 patients had evidence of recurrent or persistent fistulas, despite having completed 6 months of TB treatment. Conclusion: At a referral hospital in an endemic area, TB was present in 7.3% of anal fistulas. Histopathological examination including ZN staining was inadequate to make the diagnosis in a third of these patients. Tissue from anal fistulas should therefore routinely be sent for TB culture as well as histopathological examination and ZN staining in areas where TB is prevalent.
- ItemOpen AccessThe WNT signalling pathway in Ewing sarcoma/primitive neuroectodermal tumour : an immunohistochemical investigation(2011) Wu, Hue-Tsi; Govender, DhirenThe WNT pathway is a major developmental pathway that plays an important role in the development of many tumours, including neuroectodermal and bone tumours. Ewing sarcoma (ES) / primitive neuroectodermal tumour (PNET) shows varying degrees of neuroectodermal differentiation and is the second commonest bone malignancy in childhood. A recent study on ES cell lines using RT-PCR analysis and biological response assays suggests that an intact WNT pathway exists in ES and that addition of exogenous WNT ligands enhances cell motility. Based on this we hypothesize that the WNT pathway may play a role in the biology of ES/PNET and we aim to investigate this by immunohistochemical stains on archival tissue.