Figure 3.

BRCA1 gene copy number and protein expression analysis on breast tumor sections. (a) Tumor cells in a BRCA1 methylated sample are seen to have reduced BRCA1 gene copy numbers (red signal) compared with centromere 17 (green signal) by FISH. Considerable heterogeneity in BRCA1 gene copy numbers was evident in all tumours analysed. (b) A BRCA1 methylated tumour section showing wild-type BRCA1 protein expression by immunostaining in normal breast ducts and (c) absent/markedly reduced BRCA1 protein expression in tumour cells. Bars = 7 μm.