Expression of BAG-1 protein correlates with aggressive behavior of prostate cancers.
BACKGROUND
Differences in tumor behavior, ranging from indolent to aggressive, create a need for novel prognostic biomarkers. BAG-1 is a co-chaperone that regulates the activity of Hsp70, Bcl-2, Raf-1, growth factor, and steroid receptors (e.g., the Androgen Receptor).


METHODS
Using immunohistochemical method, we explored BAG-1 expression in prostate cancers and its association with clinicopathological parameters.


RESULTS
BAG-1 immunostaining was elevated in prostate cancer compared to normal prostatic epithelium. Higher nuclear BAG-1 in hormone-refractory (n = 34) compared to localized untreated tumors (n = 58) (P < 0.0001) suggested that upregulation of the nuclear isoform may contribute to disease progression. In 64 early-stage patients (T2N0M0) treated with external-beam irradiation, cytosolic BAG-1 correlated with higher pretreatment levels of serum Prostate specific antigen (P = 0.04) and shorter time to disease progression (P = 0.00004).


CONCLUSIONS
Increased cytosolic and nuclear BAG-1 expression may denote more aggressive variants of prostate cancer.
Krajewska
Maryla
M
Burnham Institute for Medical Research, La Jolla, California, USA.
Turner
Bruce C
BC
Shabaik
Ahmed
A
Krajewski
Stan
S
Reed
John C
JC
D014408:Biomarkers, Tumor / Q000032:analysis; D002467:Cell Nucleus / Q000737:chemistry; D003600:Cytosol / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D003627:Data Interpretation, Statistical; D018450:Disease Progression; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D009361:Neoplasm Invasiveness; D011379:Prognosis; D011467:Prostate / Q000737:chemistry; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000378:metabolism* / Q000473:pathology* / Q000532:radiotherapy; D014157:Transcription Factors / Q000032:analysis / Q000235:genetics / Q000378:metabolism*
C091732:BCL2-associated athanogene 1 protein; D014408:Biomarkers, Tumor; D004268:DNA-Binding Proteins; D014157:Transcription Factors; D017430:Prostate-Specific Antigen