Reverse Phase Protein Lysate Array (RPPA) Identifies Differential Protein Expression in Uterine Carcinosarcoma.
Elizabeth D Euscher, Caimiao Wei, Broaddus R Russell. MD Anderson Cancer Center, Houston, TX
Background: Uterine carcinosarcoma (CS) is a highly aggressive tumor characterized by admixtures of carcinoma (CA) and sarcoma (SA). Although the biphasic pattern of CS is diagnostic, individual tumors have marked heterogeneity with respect to differentiation. We adapted RPPA to the use of formalin-fixed, paraffin embedded sections of uterine CS to determine if differential patterns of protein expression correlate with histologic features of CS.
Design: We evaluated 52 uterine CS for histologic subtype of CA, presence/histologic subtype of heterologous elements (HE), ratio of CA to SA, depth of myoinvasion (MI), presence of CA or SA in MI, lymphovascular invasion, presence/histology of lymph node metastases, and presence/histology of recurrences. 50 µg of tumor protein were extracted from each block, and these proteins were subjected to RPPA analysis using a panel of 120 different antibodies previously validated for this assay.
Results: CS with HE showed the most prominent differences in protein expression. Twenty-eight proteins were differentially expressed in CS with chondrosarcoma (ChS) or rhabdomyosarcoma (RS) compared to CS without RS or ChS. These findings are summarized in tables 1 and 2.