Succinic semialdehyde derived from the gut microbiota can promote the proliferation of adult T-cell leukemia/lymphoma cells.

Adult T-cell leukemia/lymphoma (ATLL) is a refractory blood cancer with severe immunodeficiency resulting from retroviral infection. ATLL develops in only 5 % of HTLV-1-infected individuals, but the entire mechanism of ATLL progression remains unknown. Since recent studies have reported that the gut microbiome influences the progression of various diseases, we hypothesized that ATLL is also related to the gut microbiome and aimed to investigate this relationship. We analyzed the taxonomic and functional profiles of the gut microbiota of ATLL patients (n = 28) and HTLV-1-infected individuals (n = 37). We found that the succinic semialdehyde (SSA) synthesis pathway was significantly enriched in the gut microbiome of ATLL patients (P = 0.000682), and Klebsiella, whose abundance was significantly greater in ATLL patients and high-risk HTLV-1-infected individuals (P = 0.0326), was the main contributor to this pathway. Administration of SSAs to ATLL cell lines resulted in significant cell proliferation. Herein, we propose that the gut microbiome can regulate ATLL progression via metabolites.