title: Neuronal protein synuclein gamma predicts poor clinical outcome in breast cancer.
abstract: Synuclein gamma (SNCG), previously identified as a breast cancer-specific gene (BCSG1), is highly expressed in breast carcinomas but not in normal epithelium. SNCG regulates many pathways in growth and progression of breast cancer. To determine if SNCG is a biomarker for clinical prognosis of breast cancer, we generated a panel of murine monoclonal antibodies (mAbs) against human SNCG and correlated SNCG protein expression in 358 clinical breast cancer specimens with clinical outcome. A panel of 14 mAbs was characterized by ELISA, immunoprecipitation (IP), Western blot, immunocytochemistry and immunohistochemistry. SNCG protein expression was determined in 438 clinical breast specimens by immunohistochemical analysis using mAb 5C5. Expression of SNCG was strongly correlated with the stage, lymph node involvement, metastasis, tumor size and Her-2 status, but its expression was not associated with ER and PR expression status. While 71.4% of advanced breast cancers were positive for SNCG expression, only 26.8% of Stage I/II breast cancers were positive for SNCG expression and 5.2% of benign hyperplasia expressed SNCG. SNCG protein was not detectable in normal tissue adjacent to breast cancer. After a median follow-up of 64 months, patients with an SNCG-positive tumor had a significantly shorter disease-free survival and overall survival and a high probability of death compared no expression of SNCG. Multivariate analysis demonstrated that SNCG was a strong independent prognostic variable. SNCG is a new unfavorable prognostic marker for breast cancer progression and a potential target for breast cancer treatment.
authors.affiliation: Department of Radiation Oncology, Peking University School of Oncology, Beijing Cancer Hospital & Institute, Beijing, China.
authors.forename: Jianping
authors.initials: J
authors.lastname: Guo
authors.forename: Chengchao
authors.initials: C
authors.lastname: Shou
authors.forename: Lin
authors.initials: L
authors.lastname: Meng
authors.forename: Beihai
authors.initials: B
authors.lastname: Jiang
authors.forename: Bin
authors.initials: B
authors.lastname: Dong
authors.forename: Lihua
authors.initials: L
authors.lastname: Yao
authors.forename: Yuntao
authors.initials: Y
authors.lastname: Xie
authors.forename: Jianzhi
authors.initials: J
authors.lastname: Zhang
authors.forename: Yiding
authors.initials: Y
authors.lastname: Chen
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Budman
authors.forename: Yuenian Eric
authors.initials: YE
authors.lastname: Shi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor / Q000032:analysis*; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D018572:Disease-Free Survival; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D053208:Kaplan-Meier Estimate; D008207:Lymphatic Metastasis; D051379:Mice; D008875:Middle Aged; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D009367:Neoplasm Staging; D011379:Prognosis; D051845:gamma-Synuclein / Q000235:genetics / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; C104249:SNCG protein, human; D051845:gamma-Synuclein