Hepatocellular carcinoma (HCC) is one of the most common causes of cancer death worldwide, yet is refractory to most current anti-cancer therapies. Non-alcoholic fatty liver disease (NAFLD) is the fastest growing cause of HCC. Kupffer cells (KCs), the resident macrophages of the liver, are hypothesized to contribute to NAFLD-induced HCC (NAFLD-HCC) development, although their precise role remains unclear. The host lab and others have recently shown that KCs are gradually lost from the murine liver as NAFLD progresses. Moreover, an almost complete absence of KCs was observed upon NAFLD-HCC development, accompanied by significant changes in the cells of the KC-niche potentially regulating KC loss. I therefore hypothesize that KCs may be protective in the setting of NAFLD-HCC. Consistent with this, my preliminary data demonstrate that specifically depleting KCs from the murine fatty liver results in accelerated NAFLD-HCC development. Thus, here, I aim to combine my expertise with human samples with a new mouse model developed in the host lab that is devoid of KCs, to assess the precise contributions of KCs to NAFLD-HCC development. I will use state-of-the-art single cell and spatial transcriptomics approaches to interrogate KC involvement in the progression to NAFLD-HCC, with the goal of identifying and validating ligand-receptor interactions between KCs and their niche cells that may be relevant for therapeutic intervention.