CD8A and neoplasm: Finally, daily 5-HTP administration to orthotopic HCC mice reduced tumor burden and maximal diameter (P < 0.001; Fig. 6A~D), coincident with MAPK activation in MLN B cells (Fig. 6E, H) and a marked expansion of IFN-γ+CD8+ T cells within the TME (P < 0.001; Fig. 6F, G).