Study of the histopathological types of cutaneous melanoma in Palmas-TO from 2001 to 2011

Genetic causal relationship between gut microbiota and cutaneous melanoma: a two-sample Mendelian randomization study

Currently, numerous studies suggest a potential association between the gut microbiota and the progression of melanoma. Hence, our objective was to examine the genetic impact of the gut microbiota on melanoma through the utilization of the Mendelian randomization (MR) approach. This research employed Bacteroides, Streptococcus, Proteobacteria, and Lachnospiraceae as exposure variables and cutaneous melanoma (CM) as the outcome in a two-sample MR analysis. In this MR research, the primary analytical approach was the random-effects inverse-variance weighting (IVW) model. Complementary methods included weighted median, MR Egger, and basic and weighted models. We assessed both heterogeneity and horizontal pleiotropy in our study, scrutinizing whether the analysis results were affected by any individual SNP. The random-effects IVW outcomes indicated that Streptococcus, Bacteroides, Lachnospiraceae and Proteobacteria had no causal relationship with CM, with odds ratios of 1.001 [95% confidence interval (CI) = 0.998-1.004, P  = 0.444], 0.999 (95% CI = 0.996-1.002, P  = 0.692), 1.001 (95% CI = 0.998-1.003, P  = 0.306), and 0.999 (95% CI = 0.997-1.002, P  = 0.998), respectively. No analyses exhibited heterogeneity, horizontal pleiotropy, or deviations. Our research determined that Bacteroides, Streptococcus, Proteobacteria, and Lachnospiraceae do not induce CM at the genetic level. However, we cannot dismiss the possibility that these four gut microbiotas might influence CM through other mechanisms.

Dysbiosis of skin microbiome and gut microbiome in melanoma progression

Background

The microbiome alterations are associated with cancer growth and may influence the immune system and response to therapy. Particularly, the gut microbiome has been recently shown to modulate response to melanoma immunotherapy. However, the role of the skin microbiome has not been well explored in the skin tumour microenvironment and the link between the gut microbiome and skin microbiome has not been investigated in melanoma progression. Therefore, the aim of the present study was to examine associations between dysbiosis in the skin and gut microbiome and the melanoma growth using MeLiM porcine model of melanoma progression and spontaneous regression.

Results

Parallel analysis of cutaneous microbiota and faecal microbiota of the same individuals was performed in 8 to 12 weeks old MeLiM piglets. The bacterial composition of samples was analysed by high throughput sequencing of the V4-V5 region of the 16S rRNA gene. A significant difference in microbiome diversity and richness between melanoma tissue and healthy skin and between the faecal microbiome of MeLiM piglets and control piglets were observed. Both Principal Coordinate Analysis and Non-metric multidimensional scaling revealed dissimilarities between different bacterial communities. Linear discriminant analysis effect size at the genus level determined different potential biomarkers in multiple bacterial communities. Lactobacillus, Clostridium sensu stricto 1 and Corynebacterium 1 were the most discriminately higher genera in the healthy skin microbiome, while Fusobacterium, Trueperella, Staphylococcus, Streptococcus and Bacteroides were discriminately abundant in melanoma tissue microbiome. Bacteroides, Fusobacterium and Escherichia-Shigella were associated with the faecal microbiota of MeLiM piglets. Potential functional pathways analysis based on the KEGG database indicated significant differences in the predicted profile metabolisms between the healthy skin microbiome and melanoma tissue microbiome. The faecal microbiome of MeLiM piglets was enriched by genes related to membrane transports pathways allowing for the increase of intestinal permeability and alteration of the intestinal mucosal barrier.

Conclusion

The associations between melanoma progression and dysbiosis in the skin microbiome as well as dysbiosis in the gut microbiome were identified. Results provide promising information for further studies on the local skin and gut microbiome involvement in melanoma progression and may support the development of new therapeutic approaches.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-022-02458-5.

RAGE Signaling in Melanoma Tumors

Despite recent progresses in its treatment, malignant cutaneous melanoma remains a cancer with very poor prognosis. Emerging evidences suggest that the receptor for advance glycation end products (RAGE) plays a key role in melanoma progression through its activation in both cancer and stromal cells. In tumors, RAGE activation is fueled by numerous ligands, S100B and HMGB1 being the most notable, but the role of many other ligands is not well understood and should not be underappreciated. Here, we provide a review of the current role of RAGE in melanoma and conclude that targeting RAGE in melanoma could be an approach to improve the outcomes of melanoma patients.