Germline and Somatic mutations in postmenopausal breast cancer patients.

OBJECTIVES: In breast cancer (BC) patients, the frequency of germline BRCA mutations (gBRCA) may vary according to the ethnic background, age, and family history of cancer. Phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) is the second most common somatic mutated gene in BC; however, the association of mutations in both genes with cancer has not been thoroughly investigated. Thus, our aims were to investigate gBRCA mutation frequency in a cohort of postmenopausal Brazilian BC patients and the association of gBRCA1/BRCA2 and PIK3CA somatic mutations. METHODS: Forty-nine postmenopausal (>55 years) and forty-one young (≤35 years) BC patients were included in this study. The postmenopausal group included patients who reported a positive family history of cancer. For these patients, gBRCA1/BRCA2 were sequenced using next-generation sequencing (NGS) or Sanger sequencing. Data for gBRCA in young patients were already available from a previous study. DNA from formalin-fixed, paraffin-embedded (FFPE) tumors was obtained from 27 postmenopausal and 41 young patients for analyzing exons 9 and 20 of PIK3CA. The association between gBRCA1/BRCA2 and somatic mutations in PIK3CA was investigated. RESULTS: The overall frequency of gBRCA1/BRCA2 among the 49 postmenopausal patients was 10.2%. The frequencies of somatic mutations in PIK3CA in the postmenopausal and young patients were 37% and 17%, respectively (ns). The most common PIK3CA mutation was found to be E454A. Nonsense and frameshift mutations, which may counteract the oncogenic potential of PIK3CA were also detected. Regardless of age, 25% of BRCA1/BRCA2 mutation carriers and non-carriers , each, had PIK3CA somatic mutations. CONCLUSIONS: Data obtained indicate that BRCA1/BRCA2 gene testing may be considered for postmenopausal patients with BC who have a family history of cancer. Although some of them are not considered pathogenic, somatic variants of PIK3CA are frequently observed in BC patients, especially in postmenopausal patients.

Clinical spectrum of Li-Fraumeni syndrome/Li-Fraumeni-like syndrome in Brazilian individuals with the TP53 p.R337H mutation.

BACKGROUND: The TP53 p.R337H germline mutation is highly prevalent among children with adrenocortical tumors (ACTs) from South and Southeast Brazil. However, the prevalence of other tumors of the Li-Fraumeni syndrome (LFS) and Li-Fraumeni-like syndrome (LFL) spectrum, the clinical outcomes and the potential tumor occurrence in relatives carrying this distinct TP53 mutation were not fully investigated. PATIENTS AND METHODS: We investigated tumor profile data and outcomes of individuals and their close relatives with the TP53 p.R337H germline mutation. A questionnaire and the Toronto protocol were used for evaluation of asymptomatic carriers of this TP53 mutation. RESULTS: The cohort of this study comprised 51 patients from 46 different families; 67% were female. All but one harbored the TP53 p.R337H mutation in heterozygous state; only one child was homozygous for this variant. Maternal allele inheritance occurred in 72% of the cases (p= 0,002). In pediatric group, ACT was the most common primary tumor at the diagnosis (55%; median age= 2 years). No patient of the pediatric group who initially presented with ACT developed a second primary tumor and 11% (n= 3) died due to complications related to the primary tumor (median follow-up time of 81.5 months, range= 3-378 months). In adult group, the main tumors at diagnosis were: adrenocortical carcinoma (ACC) (23%; median age= 29.5 years), breast cancer (12%; median age= 38.5 years), soft tissue sarcoma (8%; median age= 50.3 years) and choroid plexus carcinoma (CPC) (2%; median age= 18 years). Among adult patients who were diagnosed with ACC as the first primary tumor, all presented with aggressive disease as per histologic and clinical criteria at diagnosis, and 75% of patients died (median follow-up time of 19 months, range= 1-69 months). Five adult patients (22%) had a second primary tumor, including bronchoalveolar lung cancer (2 cases), ACC, uterine cervical carcinoma and fibrosarcoma. The diagnosis of these tumors was established from 8 to 36 months after the first primary tumor. Three families presented more than one case of ACT. Nine malignant neoplasms were diagnosed in asymptomatic carriers using Toronto protocol. CONCLUSIONS: This study confirms a high frequency of TP53 p.R337H mutation in pediatric group with ACT. In addition, we observed the occurrence of other tumors of LFS/LFL spectrum and a difference in the aggressiveness of ACTs depending on the age group in which they were diagnosed. The predominance of maternal mutated allele inheritance was first demonstrated in the affected Brazilian's families.

Germline and Somatic mutations in postmenopausal breast cancer patients

OBJECTIVES: In breast cancer (BC) patients, the frequency of germline BRCA mutations (gBRCA) may vary according to the ethnic background, age, and family history of cancer. Phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) is the second most common somatic mutated gene in BC; however, the association of mutations in both genes with cancer has not been thoroughly investigated. Thus, our aims were to investigate gBRCA mutation frequency in a cohort of postmenopausal Brazilian BC patients and the association of gBRCA1/BRCA2 and PIK3CA somatic mutations. METHODS: Forty-nine postmenopausal (>55 years) and forty-one young (≤35 years) BC patients were included in this study. The postmenopausal group included patients who reported a positive family history of cancer. For these patients, gBRCA1/BRCA2 were sequenced using next-generation sequencing (NGS) or Sanger sequencing. Data for gBRCA in young patients were already available from a previous study. DNA from formalin-fixed, paraffin-embedded (FFPE) tumors was obtained from 27 postmenopausal and 41 young patients for analyzing exons 9 and 20 of PIK3CA. The association between gBRCA1/BRCA2 and somatic mutations in PIK3CA was investigated. RESULTS: The overall frequency of gBRCA1/BRCA2 among the 49 postmenopausal patients was 10.2%. The frequencies of somatic mutations in PIK3CA in the postmenopausal and young patients were 37% and 17%, respectively (ns). The most common PIK3CA mutation was found to be E454A. Nonsense and frameshift mutations, which may counteract the oncogenic potential of PIK3CA were also detected. Regardless of age, 25% of BRCA1/BRCA2 mutation carriers and non-carriers , each, had PIK3CA somatic mutations. CONCLUSIONS: Data obtained indicate that BRCA1/BRCA2 gene testing may be considered for postmenopausal patients with BC who have a family history of cancer. Although some of them are not considered pathogenic, somatic variants of PIK3CA are frequently observed in BC patients, especially in postmenopausal patients.