Differences in genome architecture patterns were observed between the identified subgroups. Two tumour genomes are shown for each of the four subgroups. (a) The BRCA1- and (b) BRCA2-related subgroups are characterised by relatively long segments of deletions with occasional high-level amplifications. (c) The simple-profile subgroup resembled the BRCA1- and BRCA2-related subgroups but displayed considerably less complex genomes. (d) The GII-high-III subgroup was characterised by small and closely spaced segments of genomic alterations throughout their tumour genomes along with occasional high-level amplifications. GII = genomic instability index.