Comparison of serum HER2/neu with immunohistochemical HER2/neu expression for the prediction of biochemical progression in metastatic prostate cancer.
OBJECTIVE
To examine whether pretreatment serum human epidermal growth factor receptor 2 (HER2/neu) and immunohistochemical HER2/neu expression predict biochemical recurrence-free survival in advanced prostate cancer.


METHODS
We studied 75 untreated patients with metastatic prostate cancer and compared them to a control group of 97 patients without histologically diagnosed prostate cancer. Serum samples were collected for HER2/neu protein analysis before the patients started endocrine therapy. HER2/neu expression in the prostate tissue was evaluated using immunohistochemical analysis.


RESULTS
Serum concentration of HER2/neu in patients with prostate cancer was significantly higher than in those without cancer (P = 0.005). Based on the median HER2/neu value, a cut-off level of 12.5 ng/mL was established to separate low from high serum HER2/neu levels. The biochemical recurrence-free survival rate was significantly lower in patients with a high serum HER2 level (P < 0.001). HER2/neu overexpression was found in 18 patients (24%) by immunohistochemical analysis. Biochemical recurrence-free survival rates did not show a statistically significant difference between HER2/neu positive and negative groups. Multivariate analysis showed that the pretreatment serum HER2/neu value was an independent predictor of biochemical recurrence (P = 0.02).


CONCLUSIONS
Pretreatment serum HER2/neu may represent a more valuable tool than immunohistochemical HER2/neu expression for the prediction of biochemical recurrence in metastatic prostate cancer patients.
Tambo
Mitsuhiro
M
Department of Urology, Kyorin University School of Medicine, Mitaka, Tokyo, Japan. tanbodes@kyorin-u.ac.jp
Higashihara
Eiji
E
Terado
Yuichi
Y
Nutahara
Kikuo
K
Okegawa
Takatsugu
T
D000368:Aged; D000369:Aged, 80 and over; D018450:Disease Progression; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D011237:Predictive Value of Tests; D011471:Prostatic Neoplasms / Q000097:blood* / Q000737:chemistry / Q000473:pathology*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis / Q000096:biosynthesis* / Q000097:blood*; D012189:Retrospective Studies
D018719:Erb-b2 Receptor Tyrosine Kinases