BCAT2 and neoplasm: We mapped pathological regions to ST spots according to their location in HE images, defining the ST spot regions as shown in Figure 8A and Figure S4A. Six key genes involved in BCAA metabolism (IL4I1, OXCT1, BCAT2, DLD, ALDH1B1, HADH) were highly expressed in the treatment-sensitive group, with OXCT1, BCAT2, DLD, ALDH1B1 and HADH showing elevated expression in tumor regions (Figure 8B).