[804] Overexpression of TCL1 in Testicular Germ Cell Tumors

D Cao, RW Allan, CC Guo, Y Peng, J Li. Washington University School of Medicine, Saint Louis; University of FLorida, Gainesville; The University of Texas-MD Anderson Cancer Center, Houston; The University of Texas-Southwestern Medical Center, Dallas

Background: The T cell leukemia/lymphoma 1 (TCL1) gene plays an important role in early embryogenesis. Recent studies have shown that in embryonic stem cells TCL1 is regulated by OCT3/4. OCT3/4 has been shown to be a sensitive diagnostic marker for testicular germ cell tumors (GCTs). The purpose of this study is to investigate the diagnostic utility of TCL1 in testicular GCTs.
Design: 88 primary [61 pure and 27 mixed, 47 with intratubular germ cell neoplasias (ITGCNs)] and 62 metastatic testicular GCTs (tumor type and component in tables 1 and 2) were retrieved for immunohistochemical staining with a TCL1 antibody. The percentage of tumor cells stained was scored semiquantitatively as: 0 (no tumor cell staining), 1+ (<=30%), 2+ (31-60%), 3+ (61-90%), and 4+ (>90%).
Results: The staining results with TCL1 were summarized in table 1 (primary) and table 2 (metastatic).

TCL1 immunostaining in 88 primary testicular GCTs
Tumor (pure or component)Staining Pattern
ITGCNs (N=47)000047 (100%)
seminomas (N=51)01(2%)2 (4%)2 (4%)46 (88%)
Spermatocytic seminomas (N=5)5 (100%)0000
ECs (N=32)29 (91%)3 (9%)000
YSTs (N=25)25 (100%)0000
Teratomas (N=20)20 (100%)0000
Choriocarcinomas (N=3)2 (67%)1(33%)000

TCL1 immunostaining in 62 metastatic testicular GCTs
Tumor typeStaining Pattern
Seminomas (N=19)1(5%)4(21%)3 (16%)2 (10%)9 (47%)
ECs (N=19)19 (100%)
YSTs (N=8)8 (100%)
Teratomas (N=11)11 (100%)
Choriocarcinomas (N=5)5 (100%)

The staining pattern was nuclear and cytoplasmic. TCL1 staining was seen in 69/70 seminoms and all 47 ITGCNs. Only 3/51 embryonal carcinomas (ECs) and 1/8 choriocarcinomas (in mononucleated trophoblasts) showed very focal weak TCL1 staining (1-5% tumor cells) whereas all spermatocytic seminomas, yolk sac tumors (YSTs), and teratomas were negative for TCL1. Normal seminferous tubules were negative for TCL1.
Conclusions: TCL1 overexpression is essentially limited to ITGCNs and seminomas. TCL1 dysregulation may play some role in the pathogenesis of ITGCNs and seminomas. TCL1 is a sensitive diagnostic marker for these 2 tumors (100% and 99%sensitivity, respectively).
Category: Genitourinary (including renal tumors)

Monday, March 22, 2010 1:00 PM

Poster Session II # 98, Monday Afternoon


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