Biotechnology and sustainable development in sub-Saharan Africa

Whether development is defined by the long-standing economic parameter of per capita gross national product (GNP) or by the newly introduced Human Development Index (HDI), which is not based exclusively on per capita GNP, the countries of sub-Saharan Africa rank at or near the bottom of the developing world. Agriculture and agro-based processing are the mainstays of the economies of the majority of these countries. Because of this, and also because many of the diseases endemic in these countries are communicable, the application of modern biotechnology (including genetic engineering, tissue culture and monoclonal antibody technology) and related biotechnologies could play an important part in creating sustainable development in the region. There is, therefore, an urgent need to train more of the region's indigenous citizens, and to equip more laboratories, in modern biotechnology. It is suggested that, in order to accelerate the harnessing of the fruits of biotechnology, more countries in the region should affiliate with the International Centre for Genetic Engineering and Biotechnology (ICGEB). It is further suggested that a regional equivalent of the ICGEB be built and the services of non-governmental biotechnology organizations used.The author is with Nnamdi Azikiwe University, P. M. B. 5025, Awka, Nigeria. Address correspondence to P. M. B. 1457, Enugu, Nigeria     

The national determinants of deforestation in sub-Saharan Africa

For decades, the dynamics of tropical deforestation in sub-Saharan Africa (SSA) have defied easy explanation. The rates of deforestation have been lower than elsewhere in the tropics, and the driving forces evident in other places, government new land settlement schemes and industrialized agriculture, have largely been absent in SSA. The context and causes for African deforestation become clearer through an analysis of new, national-level data on forest cover change for SSA countries for the 2000–2005 period. The recent dynamic in SSA varies from dry to wet biomes. Deforestation occurred at faster rates in nations with predominantly dry forests. The wetter Congo basin countries had lower rates of deforestation, in part because tax receipts from oil and mineral industries in this region spurred rural to urban migration, declines in agriculture and increased imports of cereals from abroad. In this respect, the Congo basin countries may be experiencing an oil and mineral fuelled forest transition. Small farmers play a more important role in African deforestation than they do in southeast Asia and Latin America, in part because small-scale agriculture remains one of the few livelihoods open to rural peoples.     

Nationalism,development, and social policy: The politics of nation-building in sub-Saharan Africa

This article examines the relationship between nation-building and social policy in post-independence sub-Saharan Africa (SSA). It argues that post-independence nationalist leaders used health, housing, and education programmes to foster a sense of national unity that would transcend the existing ethnic divisions created by the arbitrary drawing of state boundaries during colonization. Yet, in SSA, the neo-liberal turn of the 1980s favoured the decline of state-level integration and solidarity, which helped trigger territorial mobilization and fragmentation. As a consequence, the politics of welfare retrenchment in SSA does more than simply reduce benefits and increase inequalities; it also potentially weakens national unity.     

Recommendations for building out mosquito-transmitted diseases in sub-Saharan Africa: the DELIVER mnemonic

In sub-Saharan Africa, most transmission of mosquito-transmitted diseases, such as malaria or dengue, occurs within or around houses. Preventing mosquito house entry and reducing mosquito production around the home would help reduce the transmission of these diseases. Based on recent research, we make key recommendations for reducing the threat of mosquito-transmitted diseases through changes to the built environment. The mnemonic, DELIVER, recommends the following best practices: (i) Doors should be screened, self-closing and without surrounding gaps; (ii) Eaves, the space between the wall and roof, should be closed or screened; (iii) houses should be Lifted above the ground; (iv) Insecticide-treated nets should be used when sleeping in houses at night; (v) houses should be Ventilated, with at least two large-screened windows to facilitate airflow; (vi) Environmental management should be conducted regularly inside and around the home; and (vii) Roofs should be solid, rather than thatch. DELIVER is a package of interventions to be used in combination for maximum impact. Simple changes to the built environment will reduce exposure to mosquito-transmitted diseases and help keep regions free from these diseases after elimination.This article is part of the theme issue ‘Novel control strategies for mosquito-borne diseases''.     

Breast cancer in the personal genomics era

Breast cancer is a heterogeneous disease with a complex etiology that develops from different cellular lineages, progresses along multiple molecular pathways, and demonstrates wide variability in response to treatment. The "standard of care" approach to breast cancer treatment in which all patients receive similar interventions is rapidly being replaced by personalized medicine, based on molecular characteristics of individual patients. Both inherited and somatic genomic variation is providing useful information for customizing treatment regimens for breast cancer to maximize efficacy and minimize adverse side effects. In this article, we review (1) hereditary breast cancer and current use of inherited susceptibility genes in patient management; (2) the potential of newly-identified breast cancer-susceptibility variants for improving risk assessment; (3) advantages and disadvantages of direct-to-consumer testing; (4) molecular characterization of sporadic breast cancer through immunohistochemistry and gene expression profiling and opportunities for personalized prognostics; and (5) pharmacogenomic influences on the effectiveness of current breast cancer treatments. Molecular genomics has the potential to revolutionize clinical practice and improve the lives of women with breast cancer.     

Variation of female and male lineages in sub-Saharan populations: the importance of sociocultural factors

In this paper, we present a study of genetic variation in sub-Saharan Africa, which is based on published and unpublished data on fast-evolving (hypervariable region 1 of mitochondrial DNA and six microsatellites of Y chromosome) and slow-evolving (haplogroup frequencies) polymorphisms of mtDNA and Y chromosome. Our study reveals a striking difference in the genetic structure of food-producer (Bantu and Sudanic speakers) and hunter-gatherer populations (Pygmies, Kung, and Hadza). In fact, the ratio of mtDNA to Y-chromosome Nupsilon is substantially higher in food producers than in hunter-gatherers as determined by fast-evolving polymorphisms (1.76 versus 0.11). This finding indicates that the two population groups differ substantially in female and male migration rate and/or effective size. The difference also persists when linguistically homogeneous populations are used and outlier populations are eliminated (1.78 vs 0.19) or when the jacknife procedure is applied to a paired population data set (1.32 to 7.84 versus 0.14 to 0.66). The higher ratio of mtDNA to Y-chromosome Nnu in food producers than in hunter-gatherers is further confirmed by the use of slow-evolving polymorphisms (1.59 to 7.91 versus 0.12 to 0.35). To explain these results, we propose a model that integrates demographic and genetic aspects and incorporates ethnographic knowledge. In such a model, the asymmetric gene flow, polyginy, and patrilocality play an important role in differentiating the genetic structure of sub-Saharan populations. The existence of an asymmetric gene flow is supported by the phylogeographic features of mtDNA and Y-chromosome haplogroups found in the two population groups. The role of polyginy and patrilocality is sustained by the evidence of a differential pressure of genetic drift and gene flow on maternal and paternal lineages of food producers and hunter-gatherers that is revealed through the analysis of mitochondrial and Y-chromosomal intrapopulational variation.     

Whole-genome single nucleotide polymorphism and mating compatibility studies reveal the presence of distinct species in sub-Saharan Africa Bemisia tabaci whiteflies

In sub-Saharan Africa cassava growing areas, two members of the Bemisia tabaci species complex termed sub-Saharan Africa 1 (SSA1) and SSA2 have been reported as the prevalent whiteflies associated with the spread of viruses that cause cassava mosaic disease (CMD) and cassava brown streak disease (CBSD) pandemics. At the peak of CMD pandemic in the late 1990s, SSA2 was the prevalent whitefly, although its numbers have diminished over the last two decades with the resurgence of SSA1 whiteflies. Three SSA1 subgroups (SG1 to SG3) are the predominant whiteflies in East Africa and vary in distribution and biological properties. Mating compatibility between SSA1 subgroups and SSA2 whiteflies was reported as the possible driver for the resurgence of SSA1 whiteflies. In this study, a combination of both phylogenomic methods and reciprocal crossing experiments were applied to determine species status of SSA1 subgroups and SSA2 whitefly populations. Phylogenomic analyses conducted with 26 548 205 bp whole genome single nucleotide polymorphisms (SNPs) and the full mitogenomes clustered SSA1 subgroups together and separate from SSA2 species. Mating incompatibility between SSA1 subgroups and SSA2 further demonstrated their distinctiveness from each other. Phylogenomic analyses conducted with SNPs and mitogenomes also revealed different genetic relationships among SSA1 subgroups. The former clustered SSA1-SG1 and SSA1-SG2 together but separate from SSA1-SG3, while the latter clustered SSA1-SG2 and SSA1-SG3 together but separate from SSA1-SG1. Mating compatibility was observed between SSA1-SG1 and SSA1-SG2, while incompatibility occurred between SSA1-SG1 and SSA1-SG3, and SSA1-SG2 and SSA1-SG3. Mating results among SSA1 subgroups were coherent with phylogenomics results based on SNPs but not the full mitogenomes. Furthermore, this study revealed that the secondary endosymbiont—Wolbachia—did not mediate reproductive success in the crossing assays carried out. Overall, using genome wide SNPs together with reciprocal crossings assays, this study established accurate genetic relationships among cassava-colonizing populations, illustrating that SSA1 and SSA2 are distinct species while at least two species occur within SSA1 species.     

Breast cancer: Actual methods of treatment and future trends

The recent ten to twenty years have seen a substantial progress in the diagnosis and treatment of breast cancer. A rapid development of various curative options has led to the improvement of treatment outcomes, while paying more and more attention to the aspects of quality of life and cosmetic effect. In our publication, we wish to outline certain trends in the development of modern treatment of breast cancer. Among topics discussed are new forms of molecular diagnostics, new approach to the idea of sentinel node biopsy, as well as new techniques for delivery of medical procedures, the increasing use of nomograms, progress in the techniques of breast conservative treatment, modern approach to occult breast lesions, the increasing use of neoadjuvant treatment and intraoperative radiotherapy.     

The moral understandings of urban children in sub-Saharan Africa. Some preliminary observations

Contemporary research regarding children's moral development has consistently cited the influential role of social experience and interaction. It is hypothesised that the child's environment will provide social experiences which once processed and catalogued, lead to the formation of moral concepts. Accepting the diversity of childhood experience globally, one might conclude that there will be similar diversity in children's moral understanding. In order to further our understanding of moral development, it is important to gain as much context-specific data from the child's perspective as possible. Research has often failed to recongnise the extent to which the child exists in an environment entirely unique to the individual. This is particularly the case in many metropolitan areas where rapid urbanization has created extreme challenges and experiences for many children. The authors of this paper propose an analytical framework employing five scales of data collection. Applied to sub-Saharan Africa, the approach aims to show the importance of allowing for the diversity of children's experience and amplifying the child's perspective if the boundaries of research in this field are to be expanded.     

Breast cancer susceptibility loci in association with age at menarche,age at natural menopause and the reproductive lifespan

Background: Genome-wide association studies have identified single nucleotide polymorphisms (SNPs) associated with breast cancer risk. Some of these loci have unknown functional significance and may mediate the effects of hormonal exposures on breast cancer risk. We examined relationships between breast cancer susceptibility variants and menstrual/reproductive factors using data from two population-based studies. Methods: The first analysis was based on a sample of 1328 women age 20–74 who participated as controls in a case–control study of breast cancer conducted in three U.S. states. We evaluated the associations between age at menarche, age at natural menopause and the reproductive lifespan with 13 previously identified breast cancer variants. Associations were also examined with a genetic score created as the sum of at-risk alleles across the 13 variants. For validation, significant results were evaluated in a second dataset comprised 1353 women age 43–86 recruited as part of a cohort study in Wisconsin. Results: Neither the genetic score nor any of the 13 variants considered individually were associated with age at menarche or reproductive lifespan. Two SNPs were associated with age at natural menopause; every increase in the minor allele (A) of rs17468277 (CASP8) was associated with a 1.12 year decrease in menopause age (p = 0.02). The minor allele (G) of rs10941679 (5p12) was associated with a 1.01 year increase in age at natural menopause (p = 0.01). The results were not replicated in the validation cohort (B = −0.61, p = 0.14 and B = −0.01, p = .0.98, respectively). Conclusions: The evaluated variants and reproductive experiences may work through separate pathways to influence breast cancer risk.     

Risk factors for breast cancer and their association with molecular subtypes in a population of Northeast Brazil

BackgroundThe risk factors for breast cancer (BC) among women in Brazilian populations are poorly understood. To date, few Brazilian studies have addressed the potential association between risk factors and molecular BC subtypes. This case-control study aimed to identify risk factors for BC in a population of Northeast Brazil.MethodsData from 313 patients with invasive BC and 321 healthy controls were obtained from medical records from two cancer treatment centres and personal interviews. Of the 313 BC patients, 224 (71.6%) had reached menopause. The following distribution of subtypes was found among 301 patients: (1) Luminal A: 54 (17.9%); (2) Luminal B: 175 (58.1%); (3) HER2/neu: 29 (9.7%); and (4) triple-negative breast cancer (TNBC): 43 (14.3%). Odds ratios (ORs) and confidence intervals (CIs) were determined using regression analysis.ResultsRegression modelling indicated that family history, obesity (≥ 30.0 kg/m²), alcohol consumption and contraceptive use increased the overall risk of BC 1.78 (95% CI: 1.22–2.59), 1.69 (95% CI: 1.08–2.63), 2.21 (95% CI: 1.44–3.39) and 2.99 (95% CI: 2.09–4.28) times, respectively. After stratification for menopausal status, alcohol consumption increased the risk of BC 4.15 (95% CI: 2.13–8.11) times, and obesity, as a single variable, increased the risk of BC 2.02 (95% CI: 1.22–3.37) times, only among postmenopausal women. In a case-control analysis, the risk of TNBC and Luminal B breast cancer were 4.06 (95% CI: 1.58–10.42) and 1.87 times (95% CI: 1.13–3.11) higher, respectively, in obese women than in non-obese women. Furthermore, alcohol consumption increased the risk of Luminal A and B subtypes 7.08 (3.40–14.73) and 1.77 (1.07–2.92) times, respectively.ConclusionFamily history, contraceptive use, obesity and alcohol consumption increased the risk of BC. Obesity and alcohol consumption differentially increased risk of TNBC and Luminal molecular subtypes.     

Fine needle aspiration of non‐small cell lung cancer: current state and future perspective

A. Fassina, R. Cappellesso, F. Simonato, C. Lanza, A. Marzari and M. Fassan Fine needle aspiration of non‐small cell lung cancer: current state and future perspective The emerging treatment revolution determined by the advent of new targeted therapies requires accurate tumour subtyping as a mandatory step in the clinical workup of patients with non‐small cell lung carcinoma (NSCLC). As a result of advanced and inoperable disease or poor performance status, in many patients, minimally invasive procedures must be employed to obtain diagnostic material. Fine needle aspiration (FNA) is a valid and widely employed alternative to either tru‐cut or open‐sky biopsy. Indeed, cytological specimens are suitable for techniques such as immunocytochemistry, mutation and microRNA analysis, and may present advantages over small biopsies especially if cell blocks are prepared and attention is paid to cytomorphology and pre‐analytic management of specimens at the time they are collected. These will allow the adequate stratification of patients into different diagnostic and prognostic classes.     

Cropland intensification mediates the radiative balance of greenhouse gas emissions and soil carbon sequestration in maize systems of sub-Saharan Africa

Sub-Saharan Africa (SSA) must undertake proper cropland intensification for higher crop yields while minimizing climate impacts. Unfortunately, no studies have simultaneously quantified greenhouse gas (GHG; CO₂, CH₄, and N₂O) emissions and soil organic carbon (SOC) change in SSA croplands, leaving it a blind spot in the accounting of global warming potential (GWP). Here, based on 2-year field monitoring of soil emissions of CO₂, CH₄, and N₂O, as well as SOC changes in two contrasting soil types (sandy vs. clayey), we provided the first, full accounting of GWP for maize systems in response to cropland intensifications (increasing nitrogen rates and in combination with crop residue return) in SSA. To corroborate our field observations on SOC change (i.e., 2-year, a short duration), we implemented a process-oriented model parameterized with field data to simulate SOC dynamic over time. We further tested the generality of our findings by including a literature synthesis of SOC change across maize-based systems in SSA. We found that nitrogen application reduced SOC loss, likely through increased biomass yield and consequently belowground carbon allocation. Residue return switched the direction of SOC change from loss to gain; such a benefit (SOC sequestration) was not compromised by CH₄ emissions (negligible) nor outweighed by the amplified N₂O emissions, and contributed to negative net GWP. Overall, we show encouraging results that, combining residue and fertilizer-nitrogen input allowed for sequestering 82–284 kg of CO₂-eq per Mg of maize grain produced across two soils. All analyses pointed to an advantage of sandy over clayey soils in achieving higher SOC sequestration targets, and thus call for a re-evaluation on the potential of sandy soils in SOC sequestration across SSA croplands. Our findings carry important implications for developing viable intensification practices for SSA croplands in mitigating climate change while securing food production.     

Immunotherapy in colorectal cancer: current achievements and future perspective

Following dramatic success in many types of advanced solid tumors, interest in immunotherapy for the treatment of colorectal cancer (CRC) is increasingly growing. Given the compelling long-term durable remission, two programmed cell death 1 (PD-1)-blocking antibodies, pembrolizumab and nivolumab (with or without Ipilimumab), have been approved for the treatment of patients with metastatic colorectal cancer (mCRC) that is mismatch-repair-deficient and microsatellite instability-high (dMMR-MSI-H). Practice-changing results of several randomized controlled trials to move immunotherapy into the first-line treatment for MSI-H metastasis cancer and earlier stage were reported successively in the past 2 years. Besides, new intriguing advances to expand the efficacy of immunotherapy to mCRC that is mismatch-repair-proficient and low microsatellite instability (pMMR-MSI-L) demonstrated the potential benefits for the vast majority of mCRC cases. Great attention is also paid to the advances in cancer vaccines and adoptive cell therapy (ACT). In this review, we summarize the above progresses, and also highlight the current predictive biomarkers of responsiveness in immunotherapy with broad clinical utility.     

乳腺癌组织及肠道微生态研究进展

乳腺癌是全球女性患病率及病死率最高的恶性肿瘤,对生命健康造成极大威胁。微生物群被认为是人体“第二基因组”,在维护人类健康中扮演着重要角色,其结构及功能紊乱与疾病发生发展密切相关。随着高通量测序等生物技术的发展,诸多研究揭示了微生物群与乳腺癌关系密切,微生物群可能通过影响雌激素代谢、干预细胞增殖与凋亡、调节免疫及炎症等途径影响乳腺癌的发生发展,并可能影响乳腺癌对化疗及免疫治疗的反应。本文就乳腺癌组织微生态与肠道微生态研究概况展开综述,并提出预防和治疗乳腺癌的新策略。

     

Tobacco and alcohol as risk factors for oesophageal cancer in a high incidence area in South Africa

BackgroundThe Eastern Cape Province of South Africa, which includes the former Transkei has high rates of squamous cell oesophageal cancer (OC), thought to be caused mainly by nutritional deficiencies and fungal contamination of staple maize. A hospital-based case-control study was conducted at three of the major referral hospitals in this region to measure, among other suspected risk factors, the relative importance of tobacco smoking and alcohol consumption for the disease in this population.MethodsIncident cases (n = 670) of OC and controls (n = 1188) were interviewed using a structured questionnaire which included questions on tobacco and alcohol-related consumption. Odds ratios (ORs) with 95% confidence intervals for each of the risk factors were calculated using unconditional multiple logistic regression models.ResultsA monotonic dose-response was observed across the categories of each tobacco-related variable in both sexes. Males and females currently smoking a total of >14 g of tobacco per day were observed to have over 4-times the odds of developing OC (males OR = 4.36, 95% CI 2.24–8.48; females OR = 4.56, 95% CI 1.46–14.30), with pipe smoking showing the strongest effect. Similar trends were observed for the alcohol-related variables. The quantity of ethanol consumed was the most important factor in OC development rather than any individual type of alcoholic beverage, especially in smokers. Males and females consuming >53 g of ethanol per day had approximately 5-times greater odds in comparison to non-drinkers (males OR = 4.72, 95% CI 2.64–8.41; females OR = 5.24, 95% CI 3.34–8.23) and 8.5 greater odds in those who smoked >14 g tobacco daily. The attributable fractions for smoking and alcohol consumption were 58% and 48% respectively, 64% for both factors combined.ConclusionTobacco and alcohol use are major risk factors for OC development in this region.ImpactThis study provides evidence for further reinforcement of cessation of smoking and alcohol consumption to curb OC development.