AIM: We investigated the association of glutathione S-transferase P1 (GSTP1) expression and methylation status with clinicopathological characteristics of estrogen receptor (ER)-positive breast cancers. MATERIALS AND METHODS: Primary ER-positive breast cancer patients (n=177, stage I-III) were retrospectively analyzed. A quantitative GSTP1 methylation assay was performed using DNA micro-dissected from formalin-fixed and paraffin-embedded (FFPE) breast surgical specimens and GSTP1 expression was examined immunohistochemically. RESULTS: GSTP1 methylation index (MI) was higher for the following patient subsets: Large-size (p=0.029), high-grade (p=0.010), human epidermal growth factor receptor-2 (HER2)-positive (p=0.024) and Ki67-positive (p=0.001) patients. In addition, GSTP1 hyper-methylation was more frequently observed in the luminal-B than the luminal-A subtype (p<0.001) and there was no significant difference in GSTP1 positivity between the two subtypes (p=0.150). CONCLUSION: GSTP1 methylation may well be associated with the pathogenesis of the biologically-aggressive phenotype in ER-positive breast cancer.
AIM: We investigated the association of glutathione S-transferase P1 (GSTP1) expression and methylation status with clinicopathological characteristics of estrogen receptor (ER)-positive breast cancers. MATERIALS AND METHODS: Primary ER-positive breast cancerpatients (n=177, stage I-III) were retrospectively analyzed. A quantitative GSTP1 methylation assay was performed using DNA micro-dissected from formalin-fixed and paraffin-embedded (FFPE) breast surgical specimens and GSTP1 expression was examined immunohistochemically. RESULTS:GSTP1 methylation index (MI) was higher for the following patient subsets: Large-size (p=0.029), high-grade (p=0.010), human epidermal growth factor receptor-2 (HER2)-positive (p=0.024) and Ki67-positive (p=0.001) patients. In addition, GSTP1 hyper-methylation was more frequently observed in the luminal-B than the luminal-A subtype (p<0.001) and there was no significant difference in GSTP1 positivity between the two subtypes (p=0.150). CONCLUSION:GSTP1 methylation may well be associated with the pathogenesis of the biologically-aggressive phenotype in ER-positive breast cancer.
Entities:
Keywords:
Breast cancer; DNA methylation; ER-positive breast cancer; glutathione S-transferase P1 (GSTP1); microdissection
Authors: Catherine L Callahan; Youjin Wang; Catalin Marian; Daniel Y Weng; Kevin H Eng; Meng-Hua Tao; Christine B Ambrosone; Jing Nie; Maurizio Trevisan; Dominic Smiraglia; Stephen B Edge; Peter G Shields; Jo L Freudenheim Journal: Epigenetics Date: 2016-05-31 Impact factor: 4.528