Clinically atypical seminomas with yolk sac tumor features.
BACKGROUND
A small subset of young men die from seminoma. Studying these high risk, clinically atypical seminomas (CASs)-aggressive tumors with visceral metastases and chemotherapy resistance-may provide clues to the nature of drug resistance and the origin of testicular cancers. We explored the possibility that these seminomas are a unique clinical and biologic entity with intrinsic yolk sac tumor (YST) features.


METHODS
We assayed available archived tissue samples (n = 22) for chemotherapy-resistance markers found in YSTs. Specifically, we analyzed tissues and clinical histories from patients with CASs (those who had visceral metastases and recurrent disease), classical seminomas, and mixed germ-cell tumors containing YST. By using immunohistochemical testing, we evaluated the expression of bone morphogenetic protein 2, alpha fetoprotein, and glutathione S-transferase (pi) [GST (pi)].


RESULTS
GST (pi) expression significantly predicted for overall survival (p = .036). In addition, according to the results of GST (pi) immunohistochemical staining, the CASs appeared to resemble YSTs more than they did classical seminomas (p = 0.043). Less-advanced tumors, both those that expressed GST (pi) and those that were negative for GST (pi), were more amenable to local therapies, and the patients who had those tumors had better clinical outcomes.


CONCLUSIONS
Results from this exploratory study suggest that certain CASs that express GST (pi) are more similar to YST than they are to classical seminomas, and that GST (pi) expression may be able to be used as a prognosticator of disease-specific survival. Such CASs thus may have a unique biologic origin that differs from that of classical seminomas. Additional studies are needed to determine the natural history and therapeutic implications of these CASs.
Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030-3721, USA.
Avik
A
Som
Li
L
Xiao
Rui
R
Zhu
Charles C
CC
Guo
Lianchun
L
Xiao
Priya
P
Rao
Eleni
E
Efstathiou
Angabin
A
Matin
Shi-Ming
SM
Tu
D014408:Biomarkers, Tumor / Q000378:metabolism*; D055396:Bone Morphogenetic Protein 2 / Q000378:metabolism; D018240:Endodermal Sinus Tumor / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D011379:Prognosis; D012189:Retrospective Studies; D018239:Seminoma / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology; D013736:Testicular Neoplasms / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology; D000509:alpha-Fetoproteins / Q000378:metabolism
C097353:AFP protein, human; C525718:BMP2 protein, human; D014408:Biomarkers, Tumor; D055396:Bone Morphogenetic Protein 2; D000509:alpha-Fetoproteins; D005982:Glutathione Transferase