Human epidermal growth factor receptor type 2 protein expression in Chinese metastatic prostate cancer patients correlates with cancer specific survival and increases after exposure to hormonal therapy.
OBJECTIVE
To investigate human epidermal growth factor receptor type 2 (HER2) protein expression and gene amplification in Chinese metastatic prostate cancer patients and their potential value as prognostic factors.


METHODS
Immunohistochemistry (IHC) was performed to investigate HER2 protein expression in prostate biopsy specimens from 104 Chinese metastatic prostate cancer patients. After 3-11 months of hormonal therapy, 12 patients underwent transurethral resection of the prostate (TURP). HER2 protein expression of TURP specimens was compared with that of the original biopsy specimens. Of these, 10 biopsy and 4 TURP specimens with HER2 IHC staining scores >or=2+ were investigated for HER2 gene amplification status by fluorescent in situ hybridization (FISH).


RESULTS
Of the 104 prostate biopsy specimens, HER2 protein expression was 0, 1+, 2+ and 3+ in 49 (47.1%), 45 (43.3%), 8 (7.7%) and 2 (1.9%) cases, respectively. There was a significant association between HER2 expression and Gleason score (P = 0.026). HER2 protein expression of prostate cancer tissues increased in 33.3% of patients after hormonal therapy. None of the 14 specimens with HER2 IHC scores >or= 2+ showed HER2 gene amplification. Patients with HER2 scores >or= 2+ had a significantly higher chance of dying from prostate cancer than those with HER2 scores of 0 (P = 0.004) and 1+ (P = 0.034). Multivariate Cox regression analysis showed that HER2 protein expression intensity was an independent predictor of cancer-related death (P = 0.039).


CONCLUSIONS
An HER2 IHC score >or= 2+ should be defined as HER2 protein overexpression in prostate cancer. Overexpression of HER2 protein in cancer tissue might suggest an increased risk of dying from prostate cancer. HER2 protein expression increases in some individual patients after hormonal therapy.
Dai
Bo
B
Department of Urology, Cancer Hospital, Fudan University, Shanghai 200032, China.
Kong
Yun-Yi
YY
Ye
Ding-Wei
DW
Ma
Chun-Guang
CG
Zhou
Xiao-Yan
XY
Yao
Xu-Dong
XD
D000368:Aged; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use; D044466:Asian People / Q000235:genetics* / Q000706:statistics & numerical data*; D001706:Biopsy; D002681:China / Q000453:epidemiology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016016:Proportional Hazards Models; D011471:Prostatic Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000401:mortality* / Q000556:secondary; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics* / Q000378:metabolism; D012307:Risk Factors
D018931:Antineoplastic Agents, Hormonal; D018719:Erb-b2 Receptor Tyrosine Kinases