[937] Evaluation of ERG Expression in Tumors from Various Organs

Haiyan Liu, Jianhui Shi, Myra Wilkerson, Ximing Yang, Fan Lin. Geisinger Medical Center, Danville, PA; Northwestern University, Chicago, IL

Background: ERG is a recently described immunohistochemical marker for prostatic adenocarcinoma. Expression of ERG has also been suggested to correlate with the poor prognosis of prostatic adenocarcinoma with Gleason score of 6 (3+3) by some investigators. However, the published data on ERG expression in tumors from other organs were limited. In this study, we investigated the expression of ERG in a large series of carcinomas from various organs using a single immunostaining system (Dako).
Design: Immunohistochemical evaluation of the expression of ERG (Epitomics, Cat. No. AC-0105RUO) on 1,094 cases of carcinomas from various organs, and normal prostatic tissue (N= 20) and normal seminal vesicles (N=20) using tissue mircroarray sections was performed. The staining intensity was graded as weak or strong. The distribution was recorded as negative (<5% of tumor cells stained), 1+ (5-25%), 2+ (26-50%), 3+ (51-75%), or 4+ (>75%).
Results: The positive staining results (%) and the total number of cases for each entity (N) are summarized in Table 1. Forty of 90 prostatic adenocarcinomas (Gleason score 3+3) were positive for ERG, with 25 of 40 cases showing diffuse and strong nuclear staining (3 or 4+). Only 1 lung adenocarcinoma showed 2+ nuclear staining. All others cases including normal prostatic tissue and seminal vesicles in this study were negative for ERG.

Table 1. Summary of Immunostaining Results on 1,094 Cases
TumorERG (positive cases and %)
Seminoma (N=30)0
Embryonal CA (N=24)0
Yolk sac tumor (N=12)0
Lung neuroendocrine CA (N=61)0
Lung ADC (N=50)1/50 (2%)
Lung SCC (N=49)0
Papillary thyroid CA (PTC, N=47)0
Follicular thyroid CA (FTC, N=37)0
Medullary thyroid CA (MTC, N=10)0
Anaplastic thyroid CA (ATC, N=5)0
Clear cell RCC (N=82)0
Papillary RCC (N=20)0
Colonic ADC (N=43)0
Esophageal ADC (N=30)0
Gastric ADC (N=21)0
Pancreatic ADC (N=50)0
Urothelial CA (N=31)0
Prostatic ADC (N=90)40/90 (44%)
Cholangiocarcinoma (N=11)0
Breast ductal CA (N=99)0
Breast lobular CA (N=48)0
Endocervical ADC (N=17)0
Endometrial CA (N= 38)0
Ovarian serous CA (N=56)0
Hepatocellular CA (N=18)0
Pancreatic endocrine neoplasm (N=15)0
Skin melanoma (N=100)0
ADC–adenocarcinoma; CA–carcinoma; RCC–renal cell carcinoma

Conclusions: Our data demonstrate that ERG is a highly specific but not very sensitive marker 1) to confirm the diagnosis of prostatic adenocarcinoma, since normal prostate does not express ERG, and 2) to identify the prostatic primary when working on a tumor of unknown origin.
Category: Genitourinary (including renal tumors)

Monday, March 19, 2012 1:00 PM

Poster Session II # 171, Monday Afternoon


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