Banca de QUALIFICAÇÃO: ANA RAFAELA DE SOUZA TIMOTEO

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE : ANA RAFAELA DE SOUZA TIMOTEO
DATA : 17/10/2016
HORA: 14:00
LOCAL: Sala Carl Peter von Dietrich - Depto. de Bioquímica - CB/UFRN
TÍTULO:

The identification and molecular caracterization of germline mutations in individuals with hereditary breast and ovarian cancer

PALAVRAS-CHAVES:

Hereditary breast and ovarian cancer; multigene analysis; germline mutations; BRCA1; BRCA2; ATM; ATR; CDH1; MLH1; MSH6.

PÁGINAS: 121
GRANDE ÁREA: Ciências Biológicas
ÁREA: Bioquímica
RESUMO:

Hereditary breast and ovarian cancer (HBOC) corresponds to 10-15% of all diagnosed cases of breast cancer in the world. The majority germline mutations are identified in BRCA1 and BRCA2 genes, however the application of multigene panels has increased the number of pathogenic variations detected in DNA repair genes. According to the current version of NCCN Guideline, mutations in BRCA1, BRCA2, TP53 and PTEN confers high risk to develop breast cancer, and mutations in CDH1, CHEK2, PALB2, ATM and BRIP can increases over than 20% this risk. We analyzed 157 individuals with personal and/or familial breast cancer history. Genomic DNA was isolated from peripheral blood through saline-based extraction and samples were analyzed using next-generation sequencing (NGS). We identified 15 pathogenic variants and 4 VUS (Variants of Uncertain Significance) in 27 individuals (27/157; 17%), in which three are asymptomatic. Seven novel variants in 4 genes were identified: BRCA1_c.3409A>G; BRCA2_g.26826_30318del, BRCA2_c.5800C>T; BRCA2_c.5228G>A; BRCA2_c.5305delG; ATM_c.634delT and ATR_c.3043C>T. Sixty-eight percent (13/19; 68%) of variants was detected in BRCA1 and BRCA2 genes, while 32% (6/19) were identified in moderate risk genes ATM (2/19); ATR (1/19); CDH1 (1/19); MLH1 (1/19) and MSH6 (1/19). The individuals were separated in two groups for comparative analysis: high-risk genes and moderate risk genes. Among three asymptomatic individuals, two present variants in moderate risk genes ATM and MLH1. Among breast cancer individuals, eighteen patients (18/24; 75%) presented mutations in high-risk genes, while six (6/24; 25%) harbored mutations in moderate risk genes. Both groups had a high incidence of early-onset breast cancer, 83%. The group of individuals harboring variants in high-risk genes presented a greater occurrence of high-grade tumors (83% vs. 67%, P= 0.0090). In the group of individuals harboring mutation in moderate risk genes, tumors presented a more aggressive phenotype with bilateral cancer (33% vs. 11%, P= 0.0002), occurrence of metastasis (33% vs. 5.6%, P<0.0001) and incidence of deaths (33% vs. 5.6%, P<0.0001). Altogether, 1/3 of variants were identified in moderate risk genes in patients presenting a more aggressive phenotype. These results reinforce the importance of applying multigene analysis in individuals at-risk for breast cancer, especially in a heterogeneous population as Brazilian.

MEMBROS DA BANCA:
Presidente - 2085604 - SUSANA MARGARIDA GOMES MOREIRA
Externo ao Programa - 2170415 - JORGE ESTEFANO SANTANA DE SOUZA
Externo ao Programa - 1804884 - VIVIAN NOGUEIRA SILBIGER