Estimation of the burden of tinea capitis among children in Africa.

Tinea capitis is a common and endemic dermatophytosis among school age children in Africa. However, the true burden of the disease is unknown in Africa. We aimed to estimate the burden of tinea capitis among children <18 years of age in Africa. A systematic review was performed using Embase, MEDLINE and the Cochrane Library of Systematic Reviews to identify articles on tinea capitis among children in Africa published between January 1990 and October 2020. The United Nation's Population data (2019) were used to identify the number of children at risk of tinea capitis in each African country. Using the pooled prevalence, the country-specific and total burden of tinea capitis was calculated. Forty studies involving a total of 229,086 children from 17/54 African countries were identified and included in the analysis. The pooled prevalence of tinea capitis was 23% (95% CI, 17%-29%) mostly caused by Trichophyton species. With a population of 600 million (46%) children, the total number of cases of tinea capitis in Africa was estimated at 138.1 (95% CI, 102.0-174.1) million cases. Over 96% (132.6 million) cases occur in sub-Saharan Africa alone. Nigeria and Ethiopia with the highest population of children contributed 16.4% (n = 98.7 million) and 8.5% (n = 52.2 million) of cases, respectively. Majority of the participants were primary school children with a mean age of 10 years. Cases are mostly diagnosed clinically. There was a large discrepancy between the clinical and mycological diagnosis. About one in every five children in Africa has tinea capitis making it one of the most common childhood conditions in the region. A precise quantification of the burden of this neglected tropical disease is required to inform clinical and public health intervention strategies.

Human-specific RNA analysis shows uncoupled epithelial-mesenchymal plasticity in circulating and disseminated tumour cells from human breast cancer xenografts.

Blood samples, bone marrow, tumours and metastases where possible were collected from SCID mice bearing orthotopic xenografts of the triple-negative MDA-MB-468 cell line or a transplantable ER-positive patient derived xenograft (ED-03), and assessed using human-specific, tandem-nested RT-qPCR for markers relating to detection of circulating (CTCs) and disseminated tumour cells (DTCs), breast cancer clinicopathology, the 'cancer stem cell' phenotype, metabolism, hypoxia and epithelial-mesenchymal plasticity (EMP). Increased levels of SNAI1, ILK, NOTCH1, CK20, and PGR, and a decrease/loss of EPCAM in CTCs/DTCs were observed relative to the primary xenograft across both models. Decreased CD24 and EGFR was restricted to the MDA-MB-468 model, while increased TFF1 was seen in the ED-03 model. The major metabolic regulator PPARGC1A, and several hypoxia-related markers (HIF1A, APLN and BNIP3) were significantly elevated in both models. Increased expression of mesenchymal markers including SNAI1 was seen across both models, however CDH1 did not decrease concordantly, and several other epithelial markers were increased, suggesting an uncoupling of EMP to produce an EMP hybrid or partial-EMT. Single cell analysis of ED-03 CTCs, although limited, indicated uncoupling of the EMP axis in single hybrid cells, rather than distinct pools of epithelial or mesenchymal-enriched cells, however dynamic heterogeneity between CTCs/DTCs cannot be ruled out. Reduced CD24 expression was observed in the MDA-MB-468 CTCs, consistent with the 'breast cancer stem cell' phenotype, and metastatic deposits in this model mostly resembled the primary xenografts, consistent with the mesenchymal-epithelial transition paradigm.

Upregulation of matrix metalloproteinases (MMPs) in breast cancer xenografts: a major induction of stromal MMP-13.

In human breast cancer (HBC), as with many carcinoma systems, most matrix metalloproteinases (MMPs) are largely expressed by the stromal cells, whereas the tumour cells are relatively silent in MMP expression. To determine the tissue source of the most relevant MMPs, we xenografted HBC cell lines and HBC tissues into the mammary fat pad (MFP) or bone of immunocompromised mice and measured the expression of human and mouse MMP-2, -9, -11, -13, membrane-type-1 MMP (MT1-MMP), MT2-MMP and MT3-MMP by species-specific real-time quantitative RT-PCR. Our data confirm a stromal origin for most tumour-associated MMPs and indicate marked and consistent upregulation of stromal (mouse) MMP-13 and MT1-MMP in all xenografts studied, irrespective of implantation in the MFP or bone environments. In addition, we show increased expression of both human MMP-13 and human MT1-MMP by the MDA-MB-231 tumour cells grown in the MFP compared to in vitro production. MMP protein and activity data confirm the upregulation of MMP mRNA production and indicate an increase in the activated MMP-2 species as a result of tumour implantation. These data directly demonstrate tumour induction of MMP production by stromal cells in both the MFP and bone environments. These xenografts are a valuable means for examining in vivo production of MMPs and suggest that MMP-13 and MT1-MMP will be relevant targets for inhibiting breast cancer progression.