Speaker: Dr Jorge Galeano (Fred Hutchinson Cancer Research Center) Abstract: The tumor-associated microbiota has been gaining significant attention due to its ability to promote cancer progression in tumors from the gastrointestinal tract. Microbiome analysis has identified the microorganisms that could be associated with cancer cell malignancy during metastasis and chemoresistance. For instance, the enrichment of Fusobacterium nucleatum in the tumor tissue has been associated with poor clinical outcomes in patients with colorectal cancer. However, it is still unknown how these microorganisms are spatially distributed across the tumor tissue and with what elements of the tumor tissue they interact with to promote cancer progression. In this work, by modifying existing technologies that can map the spatial distribution of RNA transcripts and protein molecules along the tumor tissue, we found that intratumoral bacteria reside in distinct microniches that are functional different from other microcompartments from the same tumor sample. The bacteria-infected microniches were characterized to be hypoxic and largely immunosuppressive with an increased infiltration of pro-inflammatory myeloid cells such as neutrophils and macrophages and excluded from T cell. Cancer epithelial cells that resided in microniches containing bacteria exhibited limited capacity to proliferate with sever chromosome instability. We conclude that intratumoral bacteria is not randomly distributed across the tumor tissue, instead they are highly organized in distinct microniches that can modulate the biological funtion of other elements of the tumor microenvironment including the anti-tumor immune response and cancer epithelial cell compartments. About the speaker: Jorge completed his medical degree at the National University of Colombia. Then he migrated to Sydney, Australia where he studied actin dynamics in cytotoxic T cells during antigen engagement with cancer cells at the University of Sydney. During his doctoral degree he investigated the molecular mechanisms that drive T cell recruitment in the tumor tissue at the EMBL Australia UNSW node. He is currently doing his postdoctoral training at the Fred Hutch, Seattle USA, where he is studying the influence of bacteria in promoting cancer development. This event will be held online. Zoom: https://uni-sydney.zoom.us/j/84087321707