Functional analysis—Make or break for cancer predictability.

Highlights: [•] Copy number variations (CNVs) are quantitative genome divergences like duplications and deletions. [•] Rare cancer CNVs affect genes associated with hereditary cancer syndromes. [•] CNV de novo mutations appear orders of magnitude more frequently than point mutations. [•] Somatic copy number aberrations (CNAs) reflect genomic instabilities acquired during tumorigenesis. [•] CNAs are generated by error-prone DNA double-strand break repair activities, which represent a potential breast cancer risk marker. [Copyright &y& Elsevier]