In contrast, we found diffuse, and irregular but distinct (2) BRCA1 protein staining with the K-18 antibody, in frozen tumor tissue from patient no. 13 with the BRCA1 mutation (Figure 6) The contiguous FFPE tissue stained with the MS110 antibody was only very weakly stained (1) (Figure 6). Here, BRCA1 is linked to neoplasm.