Abstract 2258: Digital whole slide quantitative image analysis of TOPO II and P53 in sarcomas evaluating both primary and lung metastatic tumors
Authors: Strack Margaret , Sandusky George , Rushing Daniel 
Published: July 2016

Sarcomas are a heterogeneous group of tumors that account for about 200,000 cancers worldwide each year (∼1% of all human malignant tumors) and represent 15% of all pediatric malignant tumors. They comprise over fifty subtypes that can broadly be classified into bone and soft-tissue sarcomas. The vast majority of sarcomas fall into the soft-tissue group, primarily connective tissues such as muscle (smooth and skeletal), fat, and blood vessels. Bone sarcomas represent only about 20% of all diagnosed sarcomas. It is estimated that over 50% of human tumors have a TP53 mutation and over 80% of tumors have dysfunctional p53 signaling. Topoisomerase II (TOPO II) is the target for many chemotherapeutic agents. TOPO II increases at the end of the S to G2 phase and pushes the cancer cell through cell division.

In this study, 84 clinical sarcomas were evaluated from the IU Medical Center clinical case files. Some were metastatic lung lesions while others were from the primary tumor. These were Liposarcoma, Leiomyosarcoma, Fibrosarcoma, Malignant Fibrous Histiosarcoma(MFH), Synovial Sarcoma, Osteosarcoma, and Ewings. Paraffin-embedded tissue blocks were obtain from Indiana University Simon Cancer Center Tissue Procurement and Indiana University Health Pathology Laboratory under approved IRB protocols. The tumors were fixed in 10% neutral buffered formalin (NBF), processed into a paraffin block, microtomed, and stained with H&E. Immunostains with both TOPOII and P53 were performed using used the DAKO platform with the LSAB2 system. Both primary antibodies were from DAKO. The slides were scanned using Aperio Imaging System was performed using the positive-pixel algorithm in Image Scope.

The results showed that the primary tumors expressed a lower level of TOPO II and P53 in the primary tumor and a higher expression in the metastatic lung lesions in the majority of the sarcomas. However, in the subgroups MFH and Fibrosarcomas were higher in the primary tumor compared to metastatic lesions. The Aperio imaging results showed that the primary tumors were 5.238% positive for TOPO II and 2.4818% positive for P53 on average compared to the metastatic lung lesions with 9.64% positive for TOPO II and 4.5692% positive for P53. In conclusion the metastatic tumors of both biomarkers were increased in the lung. The conclusion suggests that TOPOII is overexpressed and driving cell division while a mutant P53 is dysfunctional and does not prevent tumor cell from going into the cell cycle. The results are consistent with previous studies showing that the metastatic lesions are in a state of cell cycling due to increased drug resistance.

Citation Format: Margaret Strack, George Sandusky, Daniel Rushing. Digital whole slide quantitative image analysis of TOPO II and P53 in sarcomas evaluating both primary and lung metastatic tumors. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2258.