APOF and neoplasm: In terms of tumor heterogeneity, for BRCA, the mRNA expression of APOF was negatively associated with TMB (R = − 0.09), MSI (R = − 0.07), NEO (R = − 0.07), HRD (R = − 0.18) and LOH (R = − 0.18) (Fig. 3A–H).