Down-regulation of human X-box binding protein 1 (hXBP-1) expression correlates with tumor progression in human prostate cancers.
BACKGROUND
In our previous study, the gene encoding the human X-box binding protein 1 (hXBP-1) was isolated as a down-regulated gene in advanced prostate cancers using cDNA-representational difference analysis (RDA). In the present investigation, we characterized alterations of hXBP-1 in prostate cancer specimens.


METHODS
Expression patterns of hXBP-1 in a series of human prostate cancers were examined by Northern blotting, mRNA in situ hybridization or immunohistochemistry. Loss of heterozygosity (LOH) analysis using microsatellite markers and gene mutation analysis in the hXBP-1 region were also performed.


RESULTS
Expression of hXBP-1 was localized in epithelial and adenocarcinoma cells of the prostate. An inverse correlation between hXBP-1 expression and histological differentiation was found in a series of prostate cancers without hormonal therapy. Majority of refractory cancer cases exhibited weak hXBP-1 expression. No allelic loss or gene mutations were found in the hXBP-1 region and its open reading frame, respectively, in the prostate cancer examined.


CONCLUSIONS
These results suggest that reduction of hXBP-1 expression may be a useful marker for prostate adenocarcinoma differentiation and progression.
Takahashi
Satoru
S
First Department of Pathology, Nagoya City University Medical School, Mizuho-Cho, Mizuho-Ku, Nagoya, Japan. sattak@med.nagoya-cu.ac.jp
Suzuki
Shugo
S
Inaguma
Shingo
S
Ikeda
Yoshihisa
Y
Cho
Young-Man
YM
Nishiyama
Naoki
N
Fujita
Tamio
T
Inoue
Takahiro
T
Hioki
Takuichi
T
Sugimura
Yoshiki
Y
Ushijima
Toshikazu
T
Shirai
Tomoyuki
T
D000230:Adenocarcinoma / Q000235:genetics* / Q000473:pathology*; D015152:Blotting, Northern; D002454:Cell Differentiation; D002471:Cell Transformation, Neoplastic; D004252:DNA Mutational Analysis; D004273:DNA, Neoplasm / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000096:biosynthesis*; D018450:Disease Progression; D015536:Down-Regulation; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D019656:Loss of Heterozygosity; D008297:Male; D018895:Microsatellite Repeats; D011379:Prognosis; D011471:Prostatic Neoplasms / Q000235:genetics* / Q000473:pathology*; D012333:RNA, Messenger / Q000032:analysis; D000071701:Regulatory Factor X Transcription Factors; D014157:Transcription Factors / Q000096:biosynthesis*
D004273:DNA, Neoplasm; D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D000071701:Regulatory Factor X Transcription Factors; D014157:Transcription Factors