title: Aberrant Keap1 methylation in breast cancer and association with clinicopathological features.
abstract: Keap1 (Kelch-like ECH-associated protein 1) is an adaptor protein that mediates the ubiquitination/degradation of genes regulating cell survival and apoptosis under oxidative stress conditions. We determined methylation status of the KEAP1 promoter in 102 primary breast cancers, 14 pre-invasive lesions, 38 paired normal breast tissues and 6 normal breast from reductive mammoplasty by quantitative methylation specific PCR (QMSP). Aberrant promoter methylation was detected in 52 out of the 102 primary breast cancer cases (51%) and 10 out of 14 pre-invasive lesions (71%). No mutations of the KEAP1 gene were identified in the 20 breast cancer cases analyzed by fluorescence based direct sequencing. Methylation was more frequent in the subgroup of patients identified as ER positive-HER2 negative tumors (66.7%) as compared with triple-negative breast cancers (35%) (p = 0.05, Chi-square test). The impact of the interactions between Er, PgR, Her2 expression and KEAP1 methylation on mortality was investigated by RECPAM multivariable statistical analysis, identifying four prognostic classes at different mortality risks. Triple-negative breast cancer patients with KEAP1 methylation had higher mortality risk than patients without triple-negative breast cancer (HR = 14.73, 95%CI: 3.65-59.37). Both univariable and multivariable COX regressions analyses showed that KEAP1 methylation was associated with a better progression free survival in patients treated with epirubicin/cyclophosfamide and docetaxel as sequential chemotherapy (HR = 0.082; 95%CI: 0.007-0.934). These results indicate that aberrant promoter methylation of the KEAP1 gene is involved in breast cancerogenesis. In addition, identifying patients with KEAP1 epigenetic abnormalities may contribute to disease progression prediction in breast cancer patients.
authors.affiliation: Laboratory of Oncology, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy.
authors.forename: Raffaela
authors.initials: R
authors.lastname: Barbano
authors.forename: Lucia Anna
authors.initials: LA
authors.lastname: Muscarella
authors.forename: Barbara
authors.initials: B
authors.lastname: Pasculli
authors.forename: Vanna Maria
authors.initials: VM
authors.lastname: Valori
authors.forename: Andrea
authors.initials: A
authors.lastname: Fontana
authors.forename: Michelina
authors.initials: M
authors.lastname: Coco
authors.forename: Annamaria
authors.initials: A
authors.lastname: la Torre
authors.forename: Teresa
authors.initials: T
authors.lastname: Balsamo
authors.forename: Maria Luana
authors.initials: ML
authors.lastname: Poeta
authors.forename: Giovanni Francesco
authors.initials: GF
authors.lastname: Marangi
authors.forename: Evaristo
authors.initials: E
authors.lastname: Maiello
authors.forename: Marina
authors.initials: M
authors.lastname: Castelvetere
authors.forename: Fabio
authors.initials: F
authors.lastname: Pellegrini
authors.forename: Roberto
authors.initials: R
authors.lastname: Murgo
authors.forename: Vito Michele
authors.initials: VM
authors.lastname: Fazio
authors.forename: Paola
authors.initials: P
authors.lastname: Parrella
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001940:Breast / Q000378:metabolism / Q000473:pathology; D001943:Breast Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology*; D003520:Cyclophosphamide / Q000627:therapeutic use; D019175:DNA Methylation / Q000235:genetics*; D018572:Disease-Free Survival; D000077143:Docetaxel; D015251:Epirubicin / Q000627:therapeutic use; D005260:Female; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics*; D053208:Kaplan-Meier Estimate; D000072019:Kelch-Like ECH-Associated Protein 1; D008875:Middle Aged; D011401:Promoter Regions, Genetic / Q000235:genetics; D012307:Risk Factors; D043823:Taxoids / Q000627:therapeutic use
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; C431364:KEAP1 protein, human; D000072019:Kelch-Like ECH-Associated Protein 1; D043823:Taxoids; D000077143:Docetaxel; D015251:Epirubicin; D003520:Cyclophosphamide