TP53BP1 and neoplasm: Next, the relationship between γ-H2AX and 53BP1 in the subcellular localization was analyzed by a dual-color IF assay in eight representative cases with higher expression percentages of tumor cells presenting foci of both γ-H2AX and 53BP1, in which the merged signals of γ-H2AX and 53BP1 labeling clearly demonstrated their co-localization in the form of yellow nuclear speckles (Figure 4C,D).