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Objectives: Kaposi's sarcoma (KS), caused by HHV-8, is the most frequent HIV-associated malignancy worldwide and remains a major scourge in Sub-Saharan Africa. KS is also endemic in much of Africa. There is a risk of misdiagnosis based solely on clinical appearance and haematoxylin and eosin (H&E) staining, especially with other reactive and neoplastic vascular proliferations which occur in the mouth. This study examined oral and cutaneous biopsies from clinically diagnosed lesions of KS in Kenya, using histopathology supplemented with immunohistochemistry (IHC) and polymerase chain reaction (PCR) for HHV-8 as confirmation of diagnosis.Methods: Biopsies of 49 lesions (28 oral, 21 cutaneous) previously diagnosed as 'KS' were re-examined by H&E staining and IHC targeting HHV-8 LANA-1. Positive controls were sections from embedded BCBL-1 cell lines. Negative controls were from three different HHV-8-negative biopsies. Confirmation of HHV-8 immunohistochemistry was sought by PCR and by determining the HHV-8 ORFK1 subtype.Results: Whilst most cases were confirmed, 12 oral and 4 cutaneous lesions displayed clinical and histological features of KS but were negative to HHV-8 IHC. These oral lesions were re-diagnosed as pyogenic granulomata (n = 6), deep mycosis (n = 1), inflamed mucosa (n = 2) or 'uncertain but not KS' (n = 3). Whilst PCR is usually helpful in differentiating HHV-8 disease, all samples were HHV-8 PCR positive, with identical sequences, suggesting cross-contamination of samples in the original pathology laboratories.Conclusion: HHV-8 IHC is essential for the correct diagnosis of KS, but due to the high level of contamination in resource-poor settings, PCR is inadvisable. [ABSTRACT FROM AUTHOR]

The aim of this study was to characterize the mycobiome associated with oral squamous-cell carcinoma (OSCC). DNA was extracted from 52 tissue biopsies (cases: 25 OSCC; controls: 27 intra-oral fibro-epithelial polyps [FEP]) and sequenced for the fungal internal transcribed spacer 2 region using Illumina™ 2 x300bp chemistry. Merged reads were classified to species level using a BLASTN-algorithm with UNITE’s named species sequences as reference. Downstream analyses were performed using QIIME™ and linear discriminant analysis effect size. A total of 364 species representing 160 genera and two phyla (Ascomycota and Basidiomycota) were identified, with Candida and Malassezia making up 48% and 11% of the average mycobiome, respectively. However, only five species and four genera were detected in ≥50% of the samples. The species richness and diversity were significantly lower in OSCC. Genera Candida,Hannaella, and Gibberella were overrepresented in OSCC;Alternaria and Trametes were more abundant in FEP. Species-wise, Candida albicans,Candida etchellsii, and a Hannaella luteola–like species were enriched in OSCC, while aHanseniaspora uvarum–like species,Malassezia restricta, andAspergillus tamariiwere the most significantly abundant in FEP. In conclusion, a dysbiotic mycobiome dominated by C. albicans was found in association with OSCC, a finding worth further investigation. [ABSTRACT FROM PUBLISHER]