Characteristics of cancer mycobiome in patients with acral melanoma.

Background: Intratumoral fungi have recently been implicated in cancer initiation and progression, with potential as biomarkers for predicting clinical outcomes and treatment response in patients with cancer. However, their role in acral melanoma (AM) has not been previously explored.

Methods: We characterized the mycobiome in AM tumor tissues and adjacent non-tumor tissues. Differences in fungal communities between the two tissues, as well as the prognostic and diagnostic potential of intratumoral fungi, and their associations with the tumor microenvironment and clinicopathologic features, were evaluated through bioinformatics and biostatistical analyses.

Results: Although some intratumoral fungi originated from adjacent tissues, AM tumors exhibited a distinct fungal composition characterized by altered species richness, community structure, and an increased Ascomycota-to-Basidiomycota ratio. Several fungal taxa were identified as potential diagnostic and prognostic biomarkers and showed significant correlations with clinical parameters and immune infiltration. Specifically, the CD68-high samples harbored greater fungal diversity and higher relative abundance of Endocarpon compared with CD68-low samples. Furthermore, fungi-bacteria interactions were characterized by significant negative correlations between their diversity, while positive interspecies interactions dominated the network.

Conclusions: These findings underscore the potential role of the cancer mycobiome in AM and offer new insights into the tumor microenvironment and its implications for cancer prevention and therapy.