title: HspBP1 levels are elevated in breast tumor tissue and inversely related to tumor aggressiveness.
abstract: HspBP1 is a co-chaperone that binds to and regulates the chaperone Hsp70 (Hsp70 is used to refer to HSPA1A and HSPA1B). Hsp70 is known to be elevated in breast tumor tissue, therefore the purpose of these studies was to quantify the expression of HspBP1 in primary breast tumors and in serum of these patients with a follow-up analysis after 6 to 7 years. Levels of HspBP1, Hsp70, and anti-HspBP1 antibodies in sera of breast cancer patients and healthy individuals were measured by enzyme-linked immunosorbent assay. Expression of HspBP1 was quantified from biopsies of tumor and normal breast tissue by Western blot analysis. The data obtained were analyzed for association with tumor aggressiveness markers and with patient outcome. The levels of HspBP1 and Hsp70 were significantly higher in sera of patients compared to sera of healthy individuals. HspBP1 antibodies did not differ significantly between groups. HspBP1 levels were significantly higher in tumor (14.46 ng/microg protein, n = 51) compared to normal adjacent tissue (3.17 ng/microg protein, n = 41, p < 0.001). Expression of HspBP1 was significantly lower in patients with lymph node metastasis and positive for estrogen receptors. HspBP1 levels were also significantly lower in patients with a higher incidence of metastasis and death following a 6 to 7-year follow-up. The HspBP1/Hsp70 molar ratio was not associated with the prognostic markers analyzed. Our results indicate that low HspBP1 expression could be a candidate tumor aggressiveness marker.
authors.affiliation: Faculdade de Biociências e Instituto de Pesquisas Biomédicas, PUCRS, Av. Ipiranga, 6690 2o andar, 90610-000, Porto Alegre, RS, Brazil.
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Souza
authors.forename: Caroline
authors.initials: C
authors.lastname: Albuquerque
authors.forename: Carolina
authors.initials: C
authors.lastname: Torronteguy
authors.forename: Antonio
authors.initials: A
authors.lastname: Frasson
authors.forename: Fabio
authors.initials: F
authors.lastname: Maito
authors.forename: Luciana
authors.initials: L
authors.lastname: Pereira
authors.forename: Vinícius
authors.initials: V
authors.lastname: Duval da Silva
authors.forename: Felipe
authors.initials: F
authors.lastname: Zerwes
authors.forename: Deborah
authors.initials: D
authors.lastname: Raynes
authors.forename: Vince
authors.initials: V
authors.lastname: Guerriero
authors.forename: Cristina
authors.initials: C
authors.lastname: Bonorino
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology; D005260:Female; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging
chemical_list: D014408:Biomarkers, Tumor; C113285:HSBP1 protein, human; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins