Apolipoprotein-D: a novel cellular marker for HGPIN and prostate cancer.
BACKGROUND
High grade prostatic intraepithelial neoplasia (HGPIN) is a putative pre-malignant lesion of the prostate. While apolipoprotein-D (Apo-D), an androgen-regulated hydrophobic transporter protein, is expressed in prostate tumors, its expression in HGPIN is unknown.


METHODS
Immunoreactivity for Apo-D and another androgen-regulated protein, prostate specific antigen (PSA), was investigated in 64 radical prostatectomy tissues by video image analysis.


RESULTS
Eighty two percent of prostatectomy specimens demonstrated moderate to strong Apo-D immunoreactivity in areas of HGPIN. In comparison, weak Apo-D immunoreactivity was observed in non-malignant areas in only 24% of specimens. The median (range) percentage cellular area of HGPIN immunopositive for Apo-D (9.7%, 0-42.9), and the cellular concentration of Apo-D (MIOD 3.1, 0-13.3), were intermediate between that of normal (area 0%, 0-53.5%, MIOD 0, 0-12.6) and early stage prostate cancer tissues (area 29.2%, 0-90.8%, MIOD 6.7, 0-28.1). This increase in Apo-D expression from non-malignant, through HGPIN to prostate cancer was statistically significant (P < 0.001), and contrasted with the decrease observed in PSA staining between adjacent areas of normal glands, HGPIN, and cancer (P = 0.026).


CONCLUSIONS
The presence of high levels of immunoreactive Apo-D in HGPIN and prostate cancer, but not in non-malignant epithelial cells, is consistent with HGPIN being an intermediate lesion in the transition to prostate cancer, and suggests that cellular Apo-D expression is a marker of malignant transformation of the prostate.
Hall
R E
RE
Department of Surgery, Flinders University and Flinders Medical Centre, Adelaide, South Australia.
Horsfall
D J
DJ
Stahl
J
J
Vivekanandan
S
S
Ricciardelli
C
C
Stapleton
A M F
AM
Scardino
P T
PT
Neufing
P
P
Tilley
Wayne D
WD
D001053:Apolipoproteins / Q000032:analysis* / Q000096:biosynthesis; D053399:Apolipoproteins D; D014408:Biomarkers, Tumor / Q000032:analysis*; D002471:Cell Transformation, Neoplastic; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007118:Immunoassay; D008297:Male; D017430:Prostate-Specific Antigen / Q000032:analysis*; D011468:Prostatectomy; D019048:Prostatic Intraepithelial Neoplasia / Q000235:genetics* / Q000473:pathology* / Q000601:surgery; D011471:Prostatic Neoplasms / Q000235:genetics* / Q000473:pathology* / Q000601:surgery; D014741:Video Recording
D001053:Apolipoproteins; D053399:Apolipoproteins D; D014408:Biomarkers, Tumor; D017430:Prostate-Specific Antigen