Severity of coronary artery disease is associated with diminished circANRIL expression: A possible blood based transcriptional biomarker in East Africa.

Antisense Noncoding RNA in the INK4 Locus (ANRIL) is the prime candidate gene at Chr9p21, the well-defined genetic risk locus associated with coronary artery disease (CAD). ANRIL and its transcript variants were investigated for the susceptibility to CAD in adipose tissues (AT) and peripheral blood mononuclear cells (PBMCs) of the study group and the impact of 9p21.3 locus mutations was further analysed. Expressions of ANRIL, circANRIL (hsa_circ_0008574), NR003529, EU741058 and DQ485454 were detected in epicardial AT (EAT) mediastinal AT (MAT), subcutaneous AT (SAT) and PBMCs of CAD patients undergoing coronary artery bypass grafting and non-CAD patients undergoing heart valve surgery. ANRIL expression was significantly upregulated, while the expression of circANRIL was significantly downregulated in CAD patients. Decreased circANRIL levels were significantly associated with the severity of CAD and correlated with aggressive clinical characteristics. rs10757278 and rs10811656 were significantly associated with ANRIL and circANRIL expressions in AT and PBMCs. The ROC-curve analysis suggested that circANRIL has high diagnostic accuracy (AUC: 0.9808, cut-off: 0.33, sensitivity: 1.0, specificity: 0.88). circANRIL has high diagnostic accuracy (AUC: 0.9808, cut-off: 0.33, sensitivity: 1.0, specificity: 0.88). We report the first data demonstrating the presence of ANRIL and its transcript variants expressions in the AT and PBMCs of CAD patients. circANRIL having a synergetic effect with ANRIL plays a protective role in CAD pathogenesis. Therefore, altered circANRIL expression may become a potential diagnostic transcriptional biomarker for early CAD diagnosis.

Breast cancer in East Africa: Prevalence and spectrum of germline SNV/indel and CNVs in BRCA1 and BRCA2 genes among breast cancer patients in Tanzania.

BACKGROUND: Growing prevalence and aggressiveness of breast cancer (BC) among East African women strongly indicate that the genetic risk factor implicated in the etiology of the disease may have a key role. Germline pathogenic variants in BRCA1 and BRCA2 (BRCA1/2) are known to increase the lifetime risk of BC. This study investigated the prevalence and spectrum of germline single nucleotide variant/insertion and deletion (SNV/indel), and copy number variations (CNVs) in BRCA1/2 among Tanzanian BC patients, and evaluated the associations of identified variants with patient's socio-demographic and histopathological characteristics. METHODS: One hundred BC patients were examined for BRCA1/2 variants using next-generation sequencing (NGS). Sanger sequencing and multiplex ligation-dependent probe amplification (MLPA) assay were performed for the confirmation of SNV/indel and CNVs, respectively. RESULTS: Six germline SNV/indel pathogenic variants were detected from six unrelated patients. Five of these variants were identified in BRCA1, and one in BRCA2. We also identified, in one patient, one variant of uncertain clinical significance (VUS). CNV was not detected in any of the BC patients. Furthermore, we found that in our cohort, BRCA1/2 variant carriers were triple-negative BC patients (p = 0.019). CONCLUSIONS: Our study provides first insight into BC genetic landscape by the use of NGS in the under-represented East African Tanzanian populations. Our findings support the importance of genetic risk factors in BC etiology in Tanzania and showed a relatively high overall prevalence (6%) of germline BRCA1/2 pathogenic variants in BC patients. Therefore, our results indicate that BRCA1/2 pathogenic variants may well contribute to BC incidence in Tanzania. Thus, the identification of frequent variants in BRCA1/2 genes will enable implementation of rapid, inexpensive population-specific BRCA1/2 genetic testing, particularly for triple-negative BC patients known for their high prevalence in Tanzania. This will, in turn, greatly contributes to provide effective therapeutic strategies.

The interplay between XPG-Asp1104His polymorphism and reproductive risk factors elevates risk of breast cancer in Tanzanian women: A multiple interaction analysis.

BACKGROUND: Reproductive history and genetics are well-known risk factors of breast cancer (BC). Little is known about how these factors interact to effect BC. This study investigated the association of ten polymorphisms in DNA repair genes with BC susceptibility in the Tanzanian samples and further analyzed the association between reproductive risk factors and disease risk METHODS: A hospital-based case-control study in 263 histopathological confirmed BC patients and 250 age-matched cancer-free controls was carried out. Allelic, genotypic, and haplotype association analyses were executed. Also, multifactor dimensionality reduction (MDR), and interaction dendrogram approaches were performed. RESULTS: The frequency of genotypic and allelic variants of XRCC1-Arg399Gln (rs25487), XRCC2-Arg188His (rs3218536), XRCC3-Thr241Met (rs861539), XPG-Asp1104His (rs17655), and MSH2-Gly322Asp (rs4987188) were significantly different between the groups (p < 0.05). Moreover, XRCC1-Arg399Gln (rs25487), XRCC3-Thr241Met (rs861539), and XPG-Asp1104His (rs17655) were associated with the increased risk of BC in co-dominant, dominant, recessive, and additive genetic-inheritance models (p < 0.05). XRCC1-Arg/Gln genotype indicated a 3.1-fold increased risk of BC in pre-menopausal patients (p = 0.001) while XPG-His/His genotype showed a 1.2-fold increased risk in younger BC patients (<40 years) (p = 0.028). Asp/His+His/His genotypes indicated a 1.3-fold increased risk of BC in PR+ patients and a 1.1-fold decreased risk of BC in luminal-A patients (p = 0.014, p = 0.020, respectively). MDR analysis revealed a positive interaction between BC and the XPG-Asp1104His (rs17655) together with family history of cancer in the first-degree relatives. Dendrogram analysis indicated that the XPG-Asp1104His (rs17655) and family history of cancer in first-degree relatives were significantly synergistic and might be associated with an elevated risk of BC in Tanzania. CONCLUSIONS: The XPG-Asp1104His (rs17655) might exert both independent and interactive effects on BC development in the Tanzanian women.

HLA-G and single nucleotide polymorphism (SNP) associations with cancer in African populations: Implications in personal medicine.

The immune system plays an important role in protecting the body against malignancy. During cancer immunoediting, the immune system can recognize and keep checking the tumor cells by down-expression of some self-molecules or by increasing expression of some novel molecules. However, the microenvironment created in the course of cancer development hampers the immune ability to recognize and destroy the transforming cells. Human Leukocyte Antigen G (HLA-G) is emerging as immune checkpoint molecule produced more by cancer cells to weaken the immune response against them. HLA-G is a non-classical HLA class I molecule which is normally expressed in immune privileged tissues as a soluble or membrane-bound protein. HLA-G locus is highly polymorphic in the non-coding 3' untranslated region (UTR) and in the 5' upstream regulatory region (5' URR). HLA-G expression is controlled by polymorphisms located in these regions, and several association studies between these polymorphic sites and disease predisposition, response to therapy, and/or HLA-G protein expression have been reported. Various polymorphisms are demonstrated to modulate its expression and this is increasingly finding more significance in cancer biology. This review focuses on the relevance of the HLA-G gene and its polymorphisms in cancer development. We highlight population genetics of HLA-G as evidence to espouse the need and importance of exploring potential utility of HLA-G in cancer diagnosis, prognosis and immunotherapy in the currently understudied African population.

The distribution of reproductive risk factors disclosed the heterogeneity of receptor-defined breast cancer subtypes among Tanzanian women.

BACKGROUND: Recent epidemiological studies suggest that reproductive factors are associated with breast cancer (BC) molecular subtypes. However, these associations have not been thoroughly studied in the African populations. The present study aimed to investigate the prevalence of BC molecular subtypes and assess their association with reproductive factors in Tanzanian BC patients. METHODS: This hospital-based case-only cross-sectional study consisted of 263 histologically confirmed BC patients in Tanzania. Clinico-pathological data, socio-demographic characteristics, anthropometric measurements, and reproductive risk factors were examined using the Chi-square test and one-way ANOVA. The association among reproductive factors and BC molecular subtypes was analyzed using multinomial logistic regression. The heterogeneity of the associations was assessed using the Wald test. RESULTS: We found evident subtype heterogeneity for reproductive factors. We observed that post-menopausal status was more prevalent in luminal-A subtype, while compared to luminal-A subtype, luminal-B and HER-2 enriched subtypes were less likely to be found in post-menopausal women (OR: 0.21, 95%CI 0.10-0.41, p = 0.001; OR: 0.39, 95%CI 0.17-0.89, p = 0.026, respectively). Also, the luminal-B subtype was more likely to be diagnosed in patients aged ≤ 40 years than the luminal-A subtype (OR: 2.80, 95%CI 1.46-5.32, p = 0.002). Women who had their first full-term pregnancy at < 30 years were more likely to be of luminal-B (OR: 2.71, 95%CI 1.18-4.17, p = 0.018), and triple-negative (OR: 2.28, 95%CI 1.02-4.07, p = 0.044) subtypes relative to luminal-A subtype. Furthermore, we observed that breastfeeding might have reduced odds of developing luminal-A, luminal-B and triple-negative subtypes. Women who never breastfed were more likely to be diagnosed with luminal-B and triple-negative subtypes when compared to luminal-A subtype (OR: 0.46, 95%CI 0.22-0.95, p = 0.035; OR: 0.41, 95%CI 0.20-0.85, p = 0.017, respectively). . CONCLUSION: Our results are the first data reporting reproductive factors heterogeneity among BC molecular subtypes in Tanzania. Our findings suggest that breast-feeding may reduce the likelihood of developing luminal-A, luminal-B, and triple-negative subtypes. Meanwhile, the first full-term pregnancy after 30 years of age could increase the chance of developing luminal-A subtype, a highly prevalent subtype in Tanzania. More interventions to promote modifiable risk factors across multiple levels may most successfully reduce BC incidence in Africa.

Relationships between visceral/subcutaneous adipose tissue FABP4 expression and coronary atherosclerosis in patients with metabolic syndrome.

BACKGROUND: Cytoplasmic fatty acid-binding proteins facilitate the transport of lipids to specific compartments in cells. Fatty acid-binding protein 4 (FABP4), also known as aP2 or A-FABP, plays a key role in the development of atherosclerosis, insulin resistance, obesity, and metabolic syndrome (MS). The FABP4 polymorphisms are associated with protein expression changes in vitro and metabolic and vascular alterations in vivo. The aim of this study was to investigate the association between FABP4 messenger ribonucleic acid (mRNA) expression levels in epicardial (EAT), pericardial (PAT), and subcutaneous adipose tissues (SAT), and the extent of coronary atherosclerosis in coronary artery disease (CAD) patients with MS. Furthermore, the relationship between the extent of coronary atherosclerosis and epicardial adipose tissue volume (EATV) and FABP4 gene variations was evaluated. PATIENTS AND METHODS: A total of 37 patients undergoing coronary artery bypass grafting because of CAD (MS CAD group) and 23 non-MS patients undergoing heart valve surgery (control group) were included. Coronary angiography was performed for all patients and the extent of coronary atherosclerosis was assessed using the Sullivan's scoring system. The mRNA expression levels of FABP4 gene in EAT, PAT, and SAT, and FABP4 polymorphisms were analyzed using the quantitative real-time polymerase chain reaction (qRT-PCR). RESULTS: An increased FABP4 expression was observed in EAT and PAT of MS CAD group compared to controls. In the MS CAD group, FABP4 mRNA expression levels in EAT was 2.8-fold higher compared to PAT. The expression of FABP4 in EAT was positively correlated with the extent of atherosclerosis and EATV in MS CAD group (r = 0.588, P= 0.001, r = 0.174, P = 0.001, respectively). There were no correlations between PAT and SAT versus the extent of atherosclerosis and EATV. The FABP4 EAT mRNA expression levels were found to significantly increase in mutant allele carriers of rs1054135, whereas they significantly decreased in mutant allele carriers of rs77878271 (T-87C) in MS CAD group (P < 0.05). The extent of atherosclerosis was also found to be significantly associated with rs1054135 (P < 0.05). A cut-off point of 57.5 cm3 EATV was used indicating the presence of CAD with a significant area under the curve of 0.783%, 98% sensitivity, and 100% specificity (95% CI 0.620-0.880; P < 0.05). CONCLUSIONS: Our study results suggest that FABP4 expression in EAT is strongly associated with the extent of atherosclerosis and EATV in MS CAD patients.

Implication of Soluble HLA-G and HLA-G +3142G/C Polymorphism in Breast Cancer Patients Receiving Adjuvant Therapy in Tanzania.

BACKGROUND: During cancer growth, immunosuppressive microenvironment is created that enables tumour cells to evade an eliminative immune response and hence manage to grow into malignancy. HLA-G, existing as either membrane-bound (mHLA-G) or soluble (sHLA-G) molecule is thought to be immunosuppressive and produced more by tumor cells. The +3142G/C polymorphism in HLA-G gene affects its expression, and G allele is considered to be a protective mutant allele associated with less expression of HLA-G. The implication of HLA-G in cancer development has been reported in different cancers and populations. But, its implication in most African populations has not yet been investigated. The aim of this study was to determine the possible associations of soluble HLA-G and HLA-G +3142G/C SNP with breast cancer. MATERIALS AND METHODS: 75 breast cancer patients and 84 normal controls were recruited in this study. The genotyping of HLA-G +3142G/C polymorphism was determined by LightSNiP typing assay using quantitative Real-Time PCR and sHLA-G levels were determined by ELISA. RESULTS: The sHLA-G levels were significantly lower in breast cancer patients than in controls (p<0.001). Also, they were significantly lower in mastectomized patients compared to non-mastectomized patients (p=0.018). The ROC analysis revealed a significant ability of sHLA-G to differentiate breast cancer patients versus normal controls (AUC=0.697, 95% CI= 0.619-0.767, p<0.001) and identify mastectomized patients (AUC=0.667, 95% CI= 0.549 to 0.772, p=0.041). The assessment of +3142G/C polymorphism revealed a relatively similar distribution of frequencies of genotypes and alleles between breast cancer patients and normal controls (p>0.05) and was neither associated with sHLA-G levels. CONCLUSION: While the +3142G/C SNP was found not to be relevant to breast cancer, the changes of sHLA-G levels in response to medical interventions such as mastectomy may be translated into its potential prognostic utility for breast cancer. More studies are needed to provide clear evidence of sHLA-G as a diagnostic and prognostic marker of breast cancer in Tanzania.
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herg1b expression as a potential specific marker in pediatric acute myeloid leukemia patients with HERG 897K/K genotype.

Human ether-a-go-go related gene (herg) encoding HERG K(+) channel has been demonstrated in many previous studies with its association to cell cycle progression and growth in tumor cells. The upregulated expression of HERG K+ channels was determined in different tumor types. Furthermore, not only full-length transcript herg1 but also a truncated isoform herg1b was shown to be expressed in cancer cells. In this study, the expression levels of herg1 and herg1b and the impact of K897T mutation on their expressions were investigated in pediatric acute myeloid leukemia (pAML). Expression levels of herg1 and herg1b isoforms were analyzed by quantitative real time polymerase chain reaction (PCR) in pAML patients together with healthy donors, and their expressions were confirmed by western blotting. The 2690 A>C nucleotide variation in KCNH2 gene corresponding to K897T amino acid change was analyzed by PCR followed by restriction enzyme digestion. herg1b overexpression was observed in tumor cells compared to healthy controls (P = .0024). However, herg1 expression was higher in healthy control cells than tumor cells (P = .001). The prevalence of polymorphic allele 897T was 26% in our patient group and 897T carriers showed increased herg1b expression compared to wild-type allele carriers. Our results demonstrate the presence of the increased levels of herg1b expression in pAML. In addition, we report for the first time that, pAML subgroup with HERG 897K/K genotype compared to 897K/T and T/T genotypes express increased levels of herg1b. In conclusion, HERG 897K/K genotype with increased level of herg1b expression might well be a prognostic marker for pAML.

PAI-1 and TNF-α profiles of adipose tissue in obese cardiovascular disease patients.

UNLABELLED: Obesity as a leading preventable cause of death worldwide is closely linked to cardiovascular disease (CVD). Plasma plasminogen activator inhibitor (PAI)-1, a potent inhibitor of plasminogen activation and fibrinolysis, is increased in many clinical situations associated with high incidence of CVD. In the obesity-linked elevation of PAI-1, evidence points to TNF-α as an important regulator of PAI-1 expression in adipose tissue. BACKGROUND: This study aims to evaluate mediastinal PAI-1 and TNF-α mRNA levels in adipose tissues (AT) and compare serum levels in obesity with and without coronary artery disease (CAD). PATIENTS AND METHODS: Obese patients with (n=37) and without CAD (n=20) were included in the study. RESULTS: The serum levels of PAI-1 and TNF-α were significantly higher in obese patients with CAD compared to obese patients without CAD. PAI-1 mRNA expression was significantly increased in mediastinal adipose tissue (MAT) of obese patients with CAD compared to those without CAD, TNF-α mRNA expressions were found to be higher in EAT (epicardial AT), MAT and SAT (subcutaneous AT) of obese patients with CAD. CONCLUSIONS: The study demonstrated a close direct relationship between TNF-α and PAI-1. PAI-1 mRNA expression strongly correlated positively with serum TNF-α in MAT, and TNF-α expressions with PAI-1 serum levels.

Identification of a novel BRCA2 and CHEK2 A-C-G-C haplotype in Turkish patients affected with breast cancer.

BACKGROUND: Many breast cancers are caused by certain rare and familial mutations in the high or moderate penetrance genes BRCA1, BRCA2 and CHEK2. The aim of this study was to examine the allele and genotype frequencies of seven mutations in BRCA1, BRCA2 and CHEK2 genes in breast cancer patients and to investigate their isolated and combined associations with breast cancer risk. METHODS: We genotyped seven mutations in BRCA1, BRCA2 and CHEK2 genes and then analyzed single variations and haplotype associations in 106 breast cancer patients and 80 healthy controls. RESULTS: We found significant associations in the analyses of CHEK2- 1100delC (p=0.001) and BRCA1-5382insC (p=0.021) mutations in breast cancer patients compared to controls. The highest risk was observed among breast cancer patients carrying both CHEK2-1100delC and BRCA2- Met784Val mutations (OR=0.093; 95%CI 0.021-0.423; p=0.001). We identified one previously undescribed BRCA2 and a CHEK2 four-marker haplotype of A-C-G-C which was overrepresented (?2=7.655; p=0.0057) in the patient group compared to controls. CONCLUSION: In this study, we identified a previously undescribed BRCA2 and CHEK2 A-C-G-C haplotype in association with the breast cancer in our population. Our results further suggest that the CHEK2-1100delC mutation in combination with BRCA2-Met784Val may lead to an unexpected high risk which needs to be confirmed in larger cohorts in order to better understand their role in the development and prognosis of breast cancer.

Mediastinal adipose tissue expresses a pathogenic profile of 11 ß-hydroxysteroid dehydrogenase Type 1, glucocorticoid receptor, and CD68 in patients with coronary artery disease.

OBJECTIVE: Cardiac visceral fat is accepted to be a new marker for cardiometabolic risk due to its association with increased cardiovascular risk factors. This study aimed to compare the expression of 11 beta hydroxysteroid dehydrogenases (11ß-HSD)-1, glucocorticoid receptor (GCR), and CD68 in mediastinal and subcutaneous adipose tissues (MAT, and SAT, respectively) and to assess their possible relationships with the development of coronary artery disease (CAD). METHODS AND RESULTS: Expression of 11ß-HSD-1, GCR, and CD68 mRNA levels were measured by quantitative real-time polymerase chain reaction in MAT and SAT tissues of 37 patients undergoing coronary artery bypass grafting due to CAD (CAD group) and 19 non-CAD patients (controls) undergoing heart valve surgery. 11ß-HSD-1 in MAT and SAT and GCR expression in MAT and SAT were found to be significantly increased in CAD group when compared with controls (P<.05, respectively). In CAD group, 11ß-HSD-1 mRNA levels were found to be significantly higher in MAT compared to SAT (P<.05). CD68 mRNA levels were significantly higher in MAT of CAD group compared to controls (P<.05). Immunohistochemical analyses demonstrated the presence of CD68+ cells and increased 11ß-HSD-1 expression in MAT of CAD group compared to SAT. CONCLUSION: The present study demonstrate that the mediastinal fat exhibits a pathogenic mRNA profile of 11ß-HSD-1, GCR, and CD68. The identification of 11ß-HSD-1 expression within the mediastinal fat, along with increased GCR expressions and the presence of CD68+ cells highlight that MAT potentially contributes to the pathogenesis of CAD.

The role of mediastinal adipose tissue 11ß-hydroxysteroid d ehydrogenase type 1 and glucocorticoid expression in the development of coronary atherosclerosis in obese patients with ischemic heart disease.

BACKGROUND: Visceral fat deposition and its associated atherogenic complications are mediated by glucocorticoids. Cardiac visceral fat comprises mediastinal adipose tissue (MAT) and epicardial adipose tissue (EAT), and MAT is a potential biomarker of risk for obese patients. AIM: Our objective was to evaluate the role of EAT and MAT 11beta-hydroxysteroid dehydrogenase type 1 (11ß-HSD-1) and glucocorticoid receptor (GCR) expression in comparison with subcutaneous adipose tissue (SAT) in the development of coronary atherosclerosis in obese patients with coronary artery disease (CAD), and to assess their correlations with CD68 and fatty acids from these tissues. METHODS AND RESULTS: Expression of 11ß-HSD-1 and GCR was measured by qRT-PCR in EAT, MAT and SAT of thirty-one obese patients undergoing coronary artery bypass grafting due to CAD (obese CAD group) and sixteen obese patients without CAD undergoing heart valve surgery (controls). 11ß-HSD-1 and GCR expression in MAT were found to be significantly increased in the obese CAD group compared with controls (p < 0.05). In the obese CAD group, 11ß-HSD-1 and GCR mRNA levels were strongly correlated in MAT. Stearidonic acid was significantly increased in EAT and MAT of the obese CAD group and arachidonic acid was significantly expressed in MAT of the obese male CAD group (p < 0.05). CONCLUSIONS: We report for the first time the increased expression of 11ß-HSD-1 and GCR in MAT compared with EAT and SAT, and also describe the interrelated effects of stearidonic acid, HOMA-IR, plasma cortisol and GCR mRNA levels, explaining 40.2% of the variance in 11ß-HSD-1 mRNA levels in MAT of obese CAD patients. These findings support the hypothesis that MAT contributes locally to the development of coronary atherosclerosis via glucocorticoid action.