Primary mucosal melanomas of the urogenital tract: a clinical, pathological, and genetic nationwide survey of Danish patients 1990-2019

PURPOSE

To describe the epidemiologic, clinical, histopathological, and genetic features of primary mucosal melanoma of the urinary tract in a national Danish cohort with cases included from the year 1990 to 2019.

MATERIAL AND METHODS

Patients of the Danish cohort were found using national databases. Only primary tumours were included in the cohort. Appropriate formalin-fixed paraffin-embedded blocks underwent next-generation sequencing.

RESULTS

Eight cases of primary urinary bladder melanomas and 18 cases of primary urethral melanomas were included. Bladder melanomas had an incidence of 0.05 cases/million/year. Mean age at diagnosis was 67 years. The most frequent primary treatment was cystectomy. Adjuvant treatment was given in three cases and consisted of chemotherapy or radiotherapy. Mutations were found in the NF1, KRAS, ATRX, TP53, RAC1, and BRAF genes. Urethral melanomas were found to have an incidence of 0.12 cases/million/year. Average age at diagnosis was 77 years. The most frequent treatment was excision of the tumour. Adjuvant treatment was given in nine cases and most frequently consisted of radiotherapy. Mutations were found in the NF1, TERT PROMOTOR, NRAS, ATRX, TP53, ATM, TSC2, and CREBBP genes. The 5-year survival of patients with bladder melanoma was 12.5% and 22.2% for patients with urethral melanoma.

CONCLUSION

Our study highlights the rarity of urinary tract melanomas and their poor prognosis. The most widely used treatment for urogenital mucosal melanoma remains surgical while adjuvant therapy strategies are evolving. Next-generation sequencing showed mutational patterns with no location-specific patterns. The most frequent mutations were in the NF1, ATRX, NRAS, and TP53 genes.

Revisiting the role of surgery in the treatment of Graves' disease

Graves' disease (GD) can be managed by antithyroid drugs (ATD), radioactive iodine (RAI) and surgery. Thyroidectomy offers the highest success rates for both primary and persistent disease, yet it is the least recommended or utilized option reaching <1% for primary disease and <25% for persistent disease. Several surveys have found surgery to be the least recommended by endocrinologists worldwide. With the development of remote access thyroidectomies and intraoperative nerve monitoring of the recurrent laryngeal nerve, combined with current knowledge of possible risks associated with RAI or failure of ATDs, revaluation of the benefit to harm ratio of surgery in the treatment of GD is warranted. The aim of this review is to discuss possible reasons for the low proportion of surgery in the treatment of GD, emphasizing an evidence-based approach to the clinicians' preferences for surgical referrals, surgical indications and confronting traditional reasons and concerns relating to the low referral rate with up-to-date data.

MicroRNA Expression Profile in Conjunctival Melanoma

PURPOSE

Conjunctival melanoma (CM) is a rare disease associated with considerable mortality. As opposed to cutaneous melanoma, the epigenetic mechanisms involved in the development of CM and other mucosal melanomas (MMs) are unclear. The purpose of this study was to identify tumor-specific and prognostic microRNA (miRNA) in CM and to compare the miRNA profile with that of MM.

METHODS

Using microarray analysis (Affymetrix) we determined the miRNA expression profile in 40 CMs compared with 7 normal conjunctival samples. Changes in miRNA expression were associated with T stage, local recurrence, metastasis, and mortality. Furthermore, the expression of six fresh frozen tissue samples of CM was compared with that of four laryngeal and sinonasal MM.

RESULTS

Our analysis revealed 24 upregulated and 1 downregulated miRNA in CM; several of these miRNAs have key functions in the pathogenesis and progression of cutaneous melanoma. Additionally, we identified seven upregulated miRNAs specific for stage-T1 and stage-T2 CM, whose expression was associated with increased tumor thickness (P = 0.007), and two upregulated miRNAs (miR-3687 and miR-3916) associated with an increased risk of local recurrence. No stage T3-specific miRNAs were identified.

CONCLUSIONS

We identified differentially expressed and potentially prognostic miRNAs in CM. Furthermore, the miRNA expression pattern of CM resembled that in MM. The identification of these differentially expressed miRNAs provides an entry point for future functional studies of miRNAs as prognostic or therapeutic targets in CM and highlights the resemblance between CM, MM, and cutaneous melanoma.

Effects of chlorination on the adhesion strength and deflocculation of activated sludge flocs

A side effect of the application of chlorine for controlling filamentous bulking is deflocculation of floc-forming bacteria, which may cause unacceptable effluent deterioration depending on dosing. It was assumed that chlorine may adversely affect the adhesion ability of floc bacteria, promoting their erosion in shear flow. The effect of chlorination on the strength of activated sludge flocs was investigated. The adhesion-erosion (AE) model developed by Mikkelsen and Keiding was used to interpret results from deflocculation tests with varying shear and solids concentration. The AE model yields the adhesion enthalpy (deltaHG/R) of cells in sludge flocs and parameters from the model were used to quantify the sludge in terms of floc strength. Two activated sludges with different initial characteristics were studied. The resulting model parameters showed that the AE model was suitable for quantifying the bond energy of particles to the activated sludge exposed to chlorine. For one activated sludge, adhesion of cells was largely unaffected by the applied chlorine doses. A second sludge showed reduced adhesion strength with chlorine, leading to increasing deflocculation. The simple batch test and AE model proved valuable for assessing the effect of chlorination on the flocs in activated sludge. By use of these procedures, it is possible to determine acceptable chlorine dosing to avoid excessive deflocculation and effluent deterioration.

In situ detection of cell surface hydrophobicity of probe-defined bacteria in activated sludge

The surface hydrophobicity of different types of bacteria in activated sludge were investigated under in situ conditions by following the adhesion of fluorescent microspheres with defined surface properties to bacterial surfaces (the MAC-method). This technique was combined with identification of the bacteria with fluorescence in situ hybridization with rRNA-targeted oligonucleotides (FISH) and could thus be used for characterization of surface properties of probe-defined bacteria directly in a complex system without prior enrichment or isolation. This MAC-FISH technique could be used for single bacteria as well as filamentous bacteria. In the investigated activated sludge from an industrial wastewater treatment plant, two types of filamentous bacteria dominated. One morphotype consistently attracted only very few hydrophobic microspheres, indicating that the thin sheath of exopolymers around the cells had a hydrophilic surface. Use of a hierarchical set of gene probes revealed that these filaments were sulphide oxidising Thiothrix spp. The other predominating filamentous morphotype had a thick, very hydrophobic exopolymeric sheath. This filamentous bacterium was found to belong to the alpha-Proteobacteria. The relevance of the significant differences in surface hydrophobicity for the two morphotypes in respect to substrate uptake and floc formation is discussed.

Quantification of the bond energy of bacteria attached to activated sludge floc surfaces

The great majority of activated sludge bacteria exist incorporated in flocs. The increase in dispersed bacteria when exposed to increasing turbulent shear rates has been successfully modelled by a model assuming that the adhesion and erosion of cells may be considered in analogy to ordinary chemical phase transitions. By this adhesion-erosion model (AE-model), an "enthalpy" of cell adhesion can be estimated, and this value in turn determines the range of shear rates in which erosion of cells predominates. Application of the model has indicated that only a mass fraction less than ca. 6-17% may be released from activated sludge, even when exposed to a severe turbulent environment, i.e. only a small fraction of the flocs is dispersible by means of erosion by turbulence. The shear sensitivity and the dispersible floc fraction were found to depend on the floc composition. A net decrease in the floc EPS content during anaerobic sludge stabilisation causes a dramatic increase in the dispersed fraction, indicating the important role of EPS for the floc strength. It was found also that activated sludge cells do not reflocculate completely after exposure to high shear rates. This may be an indication that the cohesion energy of bacteria growing in colonies is greater than the energy of the more stochastic adhesion of dispersed cells to floc surfaces. It could also be another indicator of the importance of entanglement forces, which do not reform instantly, once broken. When the bond strength of cell attachment to sludge surfaces is altered by changes in the chemical environment, this may cause a change in the dispersible floc fraction as well as a change in the shear range of erosion. When the shear sensitivity constant kss is adopted for sludge characterisation, an increased degree of dispersion under standard test conditions will result in increased shear sensitivity estimates. The shear sensitivity may be used for the estimation of en equivalent change in the Gibb's energy of cell adhesion (delta (delta Gad/RT)).

Effects of solids concentration on activated sludge deflocculation, conditioning and dewatering

Optimum conditioning of activated sludge in terms of minimum CST was shown to correspond to the complete removal of turbidity, and the increase in turbidity with shear due to e.g. pumping is therefore expected to affect conditioning. The optimum polymer dosage was directly related to the turbidity of activated sludge after two minutes shear, and was considerably lower than the dosage required for charge neutralisation. The turbidity produced by shear increased more than is proportional with solids concentration and was directly related to the apparent viscosity. It is suggested that increasing solids concentration causes increased surface erosion when network structures are broken, and this causes increases in turbidity and required polymer dosage per solids mass. For Aby activated sludge, optimum polymer dosage per solids mass increased by 52% when the solids concentration was increased from 8.2 to 13.7 g SS/l. Modelling of the effect of solids concentration predicts even higher increases in required polymer dosage for higher solids concentrations. This means that reduced thickening prior to pumping and conditioning may be desirable when the hydraulic capacity of the dewatering device is sufficient. Similar trends were observed for an anaerobically digested sludge. For this sludge, reduction of turbidity with FeCl3 reduced the polymer demand.