[841] Expression of CD30, oct3/4 and SOX-2 in Embryonal Carcinoma (EC) Component of Multi-Relapsed or Chemotherapy (CT) Refractory Germ-Cell Tumor (GCT)

Maurizio Colecchia, Nicolai Nicola, Salvioni Roberto, Necchi Andrea, Paolini Biagio. Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Milano, Italy

Background: CD30, Oct3/4 and SOX-2 are consistently expressed in embryonal carcinoma (EC). Our aim was to examine changes in the expression of this markers in EC after chemotherapy (CT) either in 1st-line or in the salvage setting.
Design: We retrieved paraffin-embedded tumor samples and clinical data of all Institutional patients who had persistence of non-teratoma viable cells after ≥ 1 platinum-based CT for advanced disease. The presence of any EC component was required and assessed by morphology and immunohistochemical staining. The entire set was re-assessed for CD30, oct3/4 and SOX-2 staining by 2 blinded referral pathologists. CD30-positivity was defined as a >80% membranous staining with moderate-to-strong intensity. Oct3/4 and Sox-2 positivity was defined as at least 50% nuclear staining with moderate-to intense staining. Clinical data (included histology of primary tumor) treatment setting and type of surgery were available.
Results: In the time-frame 12/1990-04/2012, a total of 245 cases with pure EC or mixed GCT residuals were treated at our Institute. Among them, 51 (retroperitoneal or mediastinal nodes, lung metastasis and liver metastasis) had complete clinical data. Tumor tissue was not available in six cases for SOX-2 and in one case for Oct3/4. Where avaible the three immunostainings were performed 35/51 (68,6%) preserved CD30 positivity, 40/50 (80%) showed Oct3/4 positivity while 29/45 (64,4%) showed SOX-2 positivity. Four cases were negative for all the immunostains.
Conclusions: As result of multiple line of platinum-based CT, EC cells showed variable loss of expression of CD30, Oct3/3 and SOX-2. This finding could represent tumor differentiation after CT and a putative explanatory mechanism in the development of chemoresistance.
Category: Genitourinary (including renal tumors)

Tuesday, March 5, 2013 1:00 PM

Poster Session IV # 210, Tuesday Afternoon


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