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Background: Age at the time of breast cancer diagnosis not only predicts clinical outcome but also indicates distinct molecular characteristics that provide the rationale for appropriate treatment strategies. However, to the authors' knowledge, little is known regarding the molecular profile and biological basis of triple-negative breast cancers (TNBCs) occurring in young and elderly patients.Methods: Using the study institution's largest, single-center, multiomics TNBC data set, the authors analyzed the clinical and genomic features of young (aged ≤39 years) and elderly (aged ≥65 years) patients with TNBC.Results: In the current study, a total of 50 patients, 354 patients, and 69 patients, respectively, were grouped as young, intermediate, and elderly patients with TNBC. Young patients with TNBC had worse short-term survival, upregulation of DNA repair, cell cycle and RNA metabolism gene sets, frequent pathogenic germline variants, and predominant homologous recombination deficiency-related mutational signatures. Several copy number alterations also were found to be enriched in young patients with TNBC. Nearly one-half of the TNBC cases in elderly patients were of the luminal androgen receptor subtype. TNBC in elderly patients was identified as being associated with severe fibrosis; a lower Ki-67 index; and somatic mutations in PIK3CA, KMT2D, ERBB2, ERBB3, and their corresponding pathways. Elderly patients with TNBC also were more likely to harbor targetable mutations.Conclusions: The findings of the current study indicated that young patients with TNBC had an enhanced cell cycle, which may have helped to explain their inferior short-term survival, whereas the homologous recombination deficiency and enriched pathogenic germline variants observed among young patients with TNBC suggested the need for genetic counseling and testing, as well as the potential use of DNA damage agents and poly(adenosine diphosphate ribose) polymerase (PARP) inhibitors. Molecular characteristics of elderly patients with TNBC, although suggesting less response to chemotherapy, provided a rationale for the routine detection of actionable somatic mutations. [ABSTRACT FROM AUTHOR]

BACKGROUND The GATA3 gene (GATA-binding protein 3) is one of the most frequently mutated genes in breast cancer. The objective of the current study was to determine the clinicopathologic characteristics of patients with breast cancer harboring GATA3 mutations. METHODS The authors examined the somatic mutation status of GATA3 and performed survival analysis in The Cancer Genome Atlas (TCGA) cohort (n = 934) and the Fudan University Shanghai Cancer Center (FUSCC) cohort (n = 308). Patient characteristics, including age; menopausal status; tumor laterality; tumor size; lymph node status; tumor grade; molecular subtypes; adjuvant radiotherapy, chemotherapy, and endocrine therapy; and prognosis, together with PIK3CA (phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha) and TP53 (tumor protein p53) mutation status, were collected. RESULTS GATA3 mutations were detected in 8.8% of patients (82 of 934 patients) in the TCGA cohort and 14.9% of patients (46 of 308 patients) in the FUSCC cohort. GATA3 mutations were found to be significantly associated with luminal-like breast cancer ( P = .002 in the TCGA cohort and P < .001 in the FUSCC cohort), and were highly mutually exclusive to PIK3CA mutations ( P = .001 in the TCGA cohort and P = .003 in the FUSCC cohort) and TP53 mutations ( P < .001 in both cohorts). Furthermore, GATA3 mutations were correlated with improved overall survival in the entire population ( P = .025 in the TCGA cohort and P = .043 in the FUSCC cohort) as well as in patients with luminal-like disease who received adjuvant endocrine therapy. CONCLUSIONS GATA3 mutations mainly occur in patients with luminal-like breast cancer and have identifiable clinicopathologic and genetic characteristics, highlighting a subgroup of patients with breast cancer in whom limited therapy may be appropriate. Cancer 2014;120:1329-1337. © 2014 American Cancer Society. [ABSTRACT FROM AUTHOR]