Ramadhani Salum Chambuso
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Previous Organizations / Institutes
The organizations / institutes from the scholar's other articles in the past ten years
Ramadhani Salum Chambuso has a total of 18 co-authors. Here are the top co-authors by number of shared publications:
Evelyn Kaambo
Department of Biochemistry and Medical Microbiology, School of Medicine, University of Namibia
4 shared publicationsAnna-Lise Williamson
Division of Medical Virology, Department of Pathology, Faculty of Health Sciences
2 shared publicationsLynette Denny
South African Medical Research Council, Clinical Gynaecological Cancer Research Centre
2 shared publicationsRaj Ramesar
MRC Unit for Genomic and Precision Medicine, Division of Human Genetics, Department of Pathology
2 shared publications- Alltalents Tutsirayi Murahwa
Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
1 shared publication Clive M. Gray
Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
1 shared publication
Latest Publications
- Open Access
- 23 April 2020
- Published by Frontiers Media SA in Frontiers in Oncology
- Vol. 10, 548
Personalized Human Papillomavirus Vaccination for Persistence of Immunity for Cervical Cancer Prevention: A Critical Review With Experts' Opinions
The development of cervical cancer has been shown to involve both viral and host factors. The host factors are those that determine the specific response to human papillomavirus (HPV) infection by the patient's immune system. The immune responses to vaccines have been shown to be influenced by polymorphisms in genes involved in innate and adaptive immunity. The specific genetic variants that may influence the immune responses to HPV vaccine which may contribute to persistence of immunity (POI) have not been widely studied yet. In order to address the question as to “is it right to vaccinate all children, and all with equal dose?” we have critically examined the knowledge of common immunogenetic and immunogenomic variations that may influence the HPV vaccine POI across various populations. We have also identified a number of specific research questions that need to be addressed in future research into host molecular genetic variations and HPV vaccine POI in order to afford life-long protection against the development of cervical cancer. This work informs future insights for improved HPV vaccine designs based on common host molecular genetic variations.
- 23 April 2020
- Published by Frontiers Media SA in Frontiers in Oncology
- Vol. 10, 548
Open AccessPersonalized Human Papillomavirus Vaccination for Persistence of Immunity for Cervical Cancer Prevention: A Critical Review With Experts' Opinions
The development of cervical cancer has been shown to involve both viral and host factors. The host factors are those that determine the specific response to human papillomavirus (HPV) infection by the patient's immune system. The immune responses to vaccines have been shown to be influenced by polymorphisms in genes involved in innate and adaptive immunity. The specific genetic variants that may influence the immune responses to HPV vaccine which may contribute to persistence of immunity (POI) have not been widely studied yet. In order to address the question as to “is it right to vaccinate all children, and all with equal dose?” we have critically examined the knowledge of common immunogenetic and immunogenomic variations that may influence the HPV vaccine POI across various populations. We have also identified a number of specific research questions that need to be addressed in future research into host molecular genetic variations and HPV vaccine POI in order to afford life-long protection against the development of cervical cancer. This work informs future insights for improved HPV vaccine designs based on common host molecular genetic variations.
- Open Access
- 1 February 2020
- Published by Wolters Kluwer Health in Medicine
- Vol. 99 (9) , e19273
Age, absolute CD4 count, and CD4 percentage in relation to HPV infection and the stage of cervical disease in HIV-1-positive women
A subgroup of women who are co-infected with human immunodeficiency virus type 1 (HIV-1) and human papillomavirus (HPV), progress rapidly to cervical disease. We characterized HPV genotypes within cervical tumor biopsies, assessed the relationships of cervical disease stage with age, HIV-1 status, absolute CD4 count, and CD4 percentage, and identified the predictive power of these variables for cervical disease stage in a cohort of South African women.We recruited 181 women who were histologically diagnosed with cervical disease; 87 were HIV-1-positive and 94 were HIV-1-seronegative. Colposcopy-directed tumor biopsies were confirmed by histology and used for genomic DNA extraction. The Roche Linear Array HPV genotyping test was used for HPV genotyping. Peripheral whole blood was used for HIV-1 rapid testing. Fully automated FC500MPL/CellMek with PanLeucogate (PLG) was used to determine absolute CD4 count, CD4 percentage, and CD45 count. Chi-squared test, a logistic regression model, parametric Pearson correlation, and ROC curves were used for statistical analyses. We used the Benjamini-Horchberg test to control for false discovery rate (FDR, q-value). All tests were significant when bothPand q were <.05.Age was a significant predictor for invasive cervical cancer (ICC) in both HIV-1-seronegative (P < .0001, q < 0.0001) and HIV-1-positive women (P= .0003, q = 0.0003). Sixty eight percent (59/87) of HIV-1-positive women with different stages of cervical disease presented with a CD4 percentage equal or less than 28%, and a median absolute CD4 count of 400 cells/μl (IQR 300–500 cells/μl). Of the HIV-1-positive women, 75% (30/40) with ICC, possessed ≤28% CD4 cells vs 25% (10/40) who possessed >28% CD4 cells (bothP < .001, q < 0.001). Furthermore, 70% (28/40) of women with ICC possessed CD4 count >350 compared to 30% (12/40) who possessed CD4 count ≤ 350 (bothP < .001, q < 0.001).Age is an independent predictor for ICC. In turn, development of ICC in HIV-1-positive women is independent of the host CD4 cells and associates with low CD4 percentage regardless of absolute CD4 count that falls within the normal range. Thus, using CD4 percentage may add a better prognostic indicator of cervical disease stage than absolute CD4 count alone.
- 1 February 2020
- Published by Wolters Kluwer Health in Medicine
- Vol. 99 (9) , e19273
Open AccessAge, absolute CD4 count, and CD4 percentage in relation to HPV infection and the stage of cervical disease in HIV-1-positive women
A subgroup of women who are co-infected with human immunodeficiency virus type 1 (HIV-1) and human papillomavirus (HPV), progress rapidly to cervical disease. We characterized HPV genotypes within cervical tumor biopsies, assessed the relationships of cervical disease stage with age, HIV-1 status, absolute CD4 count, and CD4 percentage, and identified the predictive power of these variables for cervical disease stage in a cohort of South African women.We recruited 181 women who were histologically diagnosed with cervical disease; 87 were HIV-1-positive and 94 were HIV-1-seronegative. Colposcopy-directed tumor biopsies were confirmed by histology and used for genomic DNA extraction. The Roche Linear Array HPV genotyping test was used for HPV genotyping. Peripheral whole blood was used for HIV-1 rapid testing. Fully automated FC500MPL/CellMek with PanLeucogate (PLG) was used to determine absolute CD4 count, CD4 percentage, and CD45 count. Chi-squared test, a logistic regression model, parametric Pearson correlation, and ROC curves were used for statistical analyses. We used the Benjamini-Horchberg test to control for false discovery rate (FDR, q-value). All tests were significant when bothPand q were <.05.Age was a significant predictor for invasive cervical cancer (ICC) in both HIV-1-seronegative (P < .0001, q < 0.0001) and HIV-1-positive women (P= .0003, q = 0.0003). Sixty eight percent (59/87) of HIV-1-positive women with different stages of cervical disease presented with a CD4 percentage equal or less than 28%, and a median absolute CD4 count of 400 cells/μl (IQR 300–500 cells/μl). Of the HIV-1-positive women, 75% (30/40) with ICC, possessed ≤28% CD4 cells vs 25% (10/40) who possessed >28% CD4 cells (bothP < .001, q < 0.001). Furthermore, 70% (28/40) of women with ICC possessed CD4 count >350 compared to 30% (12/40) who possessed CD4 count ≤ 350 (bothP < .001, q < 0.001).Age is an independent predictor for ICC. In turn, development of ICC in HIV-1-positive women is independent of the host CD4 cells and associates with low CD4 percentage regardless of absolute CD4 count that falls within the normal range. Thus, using CD4 percentage may add a better prognostic indicator of cervical disease stage than absolute CD4 count alone.
- Open Access
- 15 October 2019
- Published by Frontiers Media SA in Frontiers in Oncology
- Vol. 9, 951
Investigation of Cervical Tumor Biopsies for Chromosomal Loss of Heterozygosity (LOH) and Microsatellite Instability (MSI) at the HLA II Locus in HIV-1/HPV Co-infected Women
Background: A subgroup of women who are co-infected with human immunodeficiency virus type 1 (HIV-1) and human papillomavirus (HPV) progress rapidly to cervical disease regardless of high CD4 counts. Chromosomal loss of heterozygosity (LOH) and microsatellite instability (MSI) are early frequent genetic alterations occurring in solid tumors. Loss of an allele or part of a chromosome can have multiple functional effects on immune response genes, oncogenes, DNA damage-repair genes, and tumor-suppressor genes. To characterize the genetic alterations that may influence rapid tumor progression in some HIV-1-positive women, the extent of LOH and MSI at the HLA II locus on chromosome 6p in cervical tumor biopsy DNA samples with regard to HIV-1/HPV co-infection in South African women was investigated. Methods: A total of 164 women with cervical disease were recruited for this study, of which 74 were HIV-1-positive and 90 were HIV-1-seronegative. DNA from cervical tumors and matched buccal swabs were used for analyses. Six fluorescently-labeled oligonucleotide primer pairs in a multiplex PCR amplification were used to study LOH and MSI. Pearson chi-squared test for homogeneity of proportions using an exact p value, a two-proportion Z-score test, ROC curves and a logistic regression model were used for statistical analyses. All p-values were corrected for false discovery rate (FDR) using the Benjamini-Hochberg test and the adjusted p-values (q-values) were reported. All tests were significant when both p and q < 0.05. Results: Tumor DNA from HIV-1/HPV co-infected women demonstrated a higher frequency of LOH/MSI at the HLA II locus on chromosome 6p21.21 than tumor DNA from HIV-1-seronegative women (D6S2447, 74.2 vs. 42.6%; p = 0.001, q = 0.003), D6S2881 at 6p21.31 (78.3 vs. 42.9%; p = 0.002, q = 0.004), D6S2666 at 6p21.32 (79 vs. 57.1%; p = 0.035, q = 0.052), and D6S2746, at 6p21.33 (64.3 vs. 29.4%; p < 0.001, q < 0.001), respectively. Conclusions: HPV infection alone can induce LOH/MSI at the HLA II locus in cervical tumor DNA, whereas HIV-1 co-infection exacerbates it, suggesting that this may accelerate cervical disease progression in a subgroup of HIV-1-positive women.
- 15 October 2019
- Published by Frontiers Media SA in Frontiers in Oncology
- Vol. 9, 951
Open AccessInvestigation of Cervical Tumor Biopsies for Chromosomal Loss of Heterozygosity (LOH) and Microsatellite Instability (MSI) at the HLA II Locus in HIV-1/HPV Co-infected Women
Background: A subgroup of women who are co-infected with human immunodeficiency virus type 1 (HIV-1) and human papillomavirus (HPV) progress rapidly to cervical disease regardless of high CD4 counts. Chromosomal loss of heterozygosity (LOH) and microsatellite instability (MSI) are early frequent genetic alterations occurring in solid tumors. Loss of an allele or part of a chromosome can have multiple functional effects on immune response genes, oncogenes, DNA damage-repair genes, and tumor-suppressor genes. To characterize the genetic alterations that may influence rapid tumor progression in some HIV-1-positive women, the extent of LOH and MSI at the HLA II locus on chromosome 6p in cervical tumor biopsy DNA samples with regard to HIV-1/HPV co-infection in South African women was investigated. Methods: A total of 164 women with cervical disease were recruited for this study, of which 74 were HIV-1-positive and 90 were HIV-1-seronegative. DNA from cervical tumors and matched buccal swabs were used for analyses. Six fluorescently-labeled oligonucleotide primer pairs in a multiplex PCR amplification were used to study LOH and MSI. Pearson chi-squared test for homogeneity of proportions using an exact p value, a two-proportion Z-score test, ROC curves and a logistic regression model were used for statistical analyses. All p-values were corrected for false discovery rate (FDR) using the Benjamini-Hochberg test and the adjusted p-values (q-values) were reported. All tests were significant when both p and q < 0.05. Results: Tumor DNA from HIV-1/HPV co-infected women demonstrated a higher frequency of LOH/MSI at the HLA II locus on chromosome 6p21.21 than tumor DNA from HIV-1-seronegative women (D6S2447, 74.2 vs. 42.6%; p = 0.001, q = 0.003), D6S2881 at 6p21.31 (78.3 vs. 42.9%; p = 0.002, q = 0.004), D6S2666 at 6p21.32 (79 vs. 57.1%; p = 0.035, q = 0.052), and D6S2746, at 6p21.33 (64.3 vs. 29.4%; p < 0.001, q < 0.001), respectively. Conclusions: HPV infection alone can induce LOH/MSI at the HLA II locus in cervical tumor DNA, whereas HIV-1 co-infection exacerbates it, suggesting that this may accelerate cervical disease progression in a subgroup of HIV-1-positive women.
- Open Access
- 1 February 2017
- Published by American Society of Clinical Oncology (ASCO) in Journal of Global Oncology
- Vol. 3 (1) , 72-78
Influence of HIV/AIDS on Cervical Cancer: A Retrospective Study From Tanzania
Purpose: Cervical cancer is the leading cause of cancer-related morbidity and mortality in women in Tanzania. Any impact of the HIV/AIDS epidemic on cervical precancerous lesions and invasive cervical cancer has a significant implication, as for any public health concern, especially in an area such as the Morogoro region in Tanzania, which has one of the highest rates of cervical cancer in the world. Methods: A comparative retrospective study was performed of 536 women screened for cervical cancer by visual inspection methods at the Morogoro Regional Referral Hospital over a period of 3 years; the women were grouped according to their HIV status. The odds ratios (OR) with 95% CIs were estimated using χ2 test and multivariate analysis. The test statistics were evaluated with a significance level of P < .05. Results: The prevalence of precancerous lesions was 71.8% in HIV-positive women and 27.3% in HIV-seronegative women. Furthermore, the prevalence of extensive or large precancerous lesions was 40.5% in HIV-positive women and 13.5% in HIV-seronegative women. The prevalence of invasive cervical cancer was 8% in HIV-seronegative women and 11% in HIV-positive women. The risk factors for the cervical lesions were HIV-positive status (OR, 6.8; 95% CI, 4.2 to 11.2; P < .001) and being older than 30 years of age (OR, 11.99; 95% CI, 6.86 to 21.21; P < .001). Conclusion: HIV/AIDS has a highly statistically significant association with ( P < .001) and a great influence on the development of cervical precancerous lesions in HIV-positive women; however, its direct involvement in the progression to invasive cervical cancer, especially in this era of highly active antiretroviral therapy, is questionable.
- 1 February 2017
- Published by American Society of Clinical Oncology (ASCO) in Journal of Global Oncology
- Vol. 3 (1) , 72-78
Open AccessInfluence of HIV/AIDS on Cervical Cancer: A Retrospective Study From Tanzania
Purpose: Cervical cancer is the leading cause of cancer-related morbidity and mortality in women in Tanzania. Any impact of the HIV/AIDS epidemic on cervical precancerous lesions and invasive cervical cancer has a significant implication, as for any public health concern, especially in an area such as the Morogoro region in Tanzania, which has one of the highest rates of cervical cancer in the world. Methods: A comparative retrospective study was performed of 536 women screened for cervical cancer by visual inspection methods at the Morogoro Regional Referral Hospital over a period of 3 years; the women were grouped according to their HIV status. The odds ratios (OR) with 95% CIs were estimated using χ2 test and multivariate analysis. The test statistics were evaluated with a significance level of P < .05. Results: The prevalence of precancerous lesions was 71.8% in HIV-positive women and 27.3% in HIV-seronegative women. Furthermore, the prevalence of extensive or large precancerous lesions was 40.5% in HIV-positive women and 13.5% in HIV-seronegative women. The prevalence of invasive cervical cancer was 8% in HIV-seronegative women and 11% in HIV-positive women. The risk factors for the cervical lesions were HIV-positive status (OR, 6.8; 95% CI, 4.2 to 11.2; P < .001) and being older than 30 years of age (OR, 11.99; 95% CI, 6.86 to 21.21; P < .001). Conclusion: HIV/AIDS has a highly statistically significant association with ( P < .001) and a great influence on the development of cervical precancerous lesions in HIV-positive women; however, its direct involvement in the progression to invasive cervical cancer, especially in this era of highly active antiretroviral therapy, is questionable.
- Open Access
- 1 January 2017
- Published by Scitechnol Biosoft Pvt. Ltd. in Journal of Neoplasm
- Vol. 02 (03)
Observed Age Difference and Clinical Characteristics of Invasive Cervical Cancer Patients in Tanzania; A Comparison between HIV-Positive and HIV-Negative Women
Objectives: Human Immunodeficiency Virus (HIV) infection may associate to invasive cervical cancer (ICC) disease course and outcome. However, there is inconsistency of data regarding to the presence of HIV infection in women with ICC from different geographical population groups. To study the current HIV association with ICC in Tanzania, we evaluated the presence of HIV infection in women diagnosed with ICC. Methods: We conducted a hospital-based study of 152 women histologically diagnosed with ICC at the Ocean Road Cancer Institute, Tanzania for one year. Rapid antibody test was used to check for HIV infection status. Chi-square test and logistic regression were used for statistical analysis and the tests were considered significant if p<0.05. Results: HIV-positive women were significantly younger than HIV-seronegative women; the median age was 36 years (IQR 28-62), compared to 56 years (IQR 38-81), respectively, p40 years. In a pooled analysis, covariates of ICC with regard to HIV infection were, age at sexual debut below 16 years (p<0.001) and low education level (p=0.001). Moreover, statistical analysis revealed that treatment comorbidity, pre-treatment blood transfusion and low pretreatment white blood cell count were significantly associated with HIV-positive status (p<0.05). Conclusion: HIV-positive women were twenty years younger than HIV-seronegative women, both diagnosed with ICC (p<0.001). A large population based case-control study would advance our understanding on the temporality of this association.
- 1 January 2017
- Published by Scitechnol Biosoft Pvt. Ltd. in Journal of Neoplasm
- Vol. 02 (03)
Open AccessObserved Age Difference and Clinical Characteristics of Invasive Cervical Cancer Patients in Tanzania; A Comparison between HIV-Positive and HIV-Negative Women
Objectives: Human Immunodeficiency Virus (HIV) infection may associate to invasive cervical cancer (ICC) disease course and outcome. However, there is inconsistency of data regarding to the presence of HIV infection in women with ICC from different geographical population groups. To study the current HIV association with ICC in Tanzania, we evaluated the presence of HIV infection in women diagnosed with ICC. Methods: We conducted a hospital-based study of 152 women histologically diagnosed with ICC at the Ocean Road Cancer Institute, Tanzania for one year. Rapid antibody test was used to check for HIV infection status. Chi-square test and logistic regression were used for statistical analysis and the tests were considered significant if p<0.05. Results: HIV-positive women were significantly younger than HIV-seronegative women; the median age was 36 years (IQR 28-62), compared to 56 years (IQR 38-81), respectively, p40 years. In a pooled analysis, covariates of ICC with regard to HIV infection were, age at sexual debut below 16 years (p<0.001) and low education level (p=0.001). Moreover, statistical analysis revealed that treatment comorbidity, pre-treatment blood transfusion and low pretreatment white blood cell count were significantly associated with HIV-positive status (p<0.05). Conclusion: HIV-positive women were twenty years younger than HIV-seronegative women, both diagnosed with ICC (p<0.001). A large population based case-control study would advance our understanding on the temporality of this association.