Significant prognostic factor of immunohistochemical HER-2 expression using initial prostate biopsy specimens with M1b prostate cancer.
BACKGROUND
We examined whether human epidermal growth factor-2(HER-2) overexpression could be a useful marker of outcome after hormone therapy in patients with M1b prostate cancer (PC).


METHODS
The subjects were 102 patients who were diagnosed with M1b PC at Aichi Medical University Hospital. HER-2 expression was determined by immunohistochemical (IHC) staining using initial needle biopsy specimens for diagnosis. The results were classified into four grades (0, 1+, 2+, 3+), and scores of 1+ or greater were considered overexpression and defined as positive.


RESULTS
The results showed a rating of 0 in 72 subjects, 1+ in 10, 2+ in 14, and 3+ in 6; 30 subjects (29.4%) were classified as HER-2 positive. Comparison of clinical data of HER-2 positive and negative subjects obtained at baseline revealed many of the subjects with high-grade tumors by Gleason score were HER-2 positive (P = 0.030). The prostate-specific antigen (PSA) relapse was observed in 76 subjects and cause-specific death occurred in 44. A significant difference was observed only in the item HER-2 (negative vs. positive) by multivariate Cox proportional hazard analysis. The 5-year PSA relapse-free rate was 0% in subjects with HER-2 positive (26/30), and 43.9% in subjects with HER-2 negative (50/72, P = 0.0192). The 5-year cause-specific survival rate was 40.9% in subjects with HER-2 positive (30/102), and 67.3% in subjects with HER-2 negative (72/102, P = 0.0301).


CONCLUSIONS
HER-2 overexpression as determined by IHC staining using needle biopsy specimens for diagnosis with M1b PC is a significant prognostic factor for PSA relapse after hormone therapy and unfavorable outcome.
Tobiume
Motoi
M
Department of Urology, Aichi Medical University School of Medicine, Nagakute-cho, Aichi, Japan.
Yamada
Yoshiaki
Y
Nakamura
Kogenta
K
Aoki
Shigeyuki
S
Zennami
Kenji
K
Kato
Yoshiharu
Y
Nishikawa
Genya
G
Yokoi
Toyoharu
T
Honda
Nobuaki
N
D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011467:Prostate / Q000473:pathology*; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000737:chemistry* / Q000401:mortality; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis*; D015996:Survival Rate
D017430:Prostate-Specific Antigen; D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human