The aggressive nature of breast cancer in young women may be related to the occurrence of
mutations in the BRCA1/BRCA2 genes responsible for DNA repair. Despite of cases are associated with and
without a family history of breast and ovarian cancer such changes are present in only a small percentage of
cases, which corresponds to 80-10% of patients with familial breast cancer and 3.2-10.6% of women with
breast cancer non-familial (sporadic). The penetrance rate of this variability is not well understood today, but
we know that reproductive factors, risks posed by particular mutations and other genetic modifiers The
expression profile of miRNAs can also reveal changes in the regulatory processes that distinguish the
appearance of cancer familial and sporadic breast cancer in young patients. miRNAs have been described as
related to the aggressiveness of breast cancer and the sensitivity of human mammary tumor strains to antiestrogen.
Such evidence indicates that the molecular mechanisms responsible for the aggressive behavior of
breast carcinoma in young women has not been sufficiently clarified.
