ErbB2 and bone sialoprotein as markers for metastatic osteosarcoma cells

Area of Science:

• Oncology
• Molecular Biology
• Hematology

Background:

• Osteosarcoma is the most common bone cancer in young patients, with poor outcomes for metastatic disease.
• High-dose chemotherapy with CD34+ leukapheresis is used for metastatic osteosarcoma, but contamination of apheresis with tumor cells can lead to relapse.

Purpose of the Study:

• To identify reliable markers for detecting osteosarcoma cells in patient apheresis products.
• To evaluate the expression of bone-specific genes (Bone Sialoprotein, Osteocalcin) and oncogenes (Met, ErbB2) as potential detection markers.

Main Methods:

• Analysis of gene expression (Bone Sialoprotein, Osteocalcin, Met, ErbB2) in apheresis samples from 22 metastatic osteosarcoma patients and 6 healthy donors.
• Utilized Reverse Transcription Polymerase Chain Reaction (RT-PCR) and Southern blot analysis to assess gene expression levels.

Main Results:

• Bone Sialoprotein (BSP) was significantly expressed in 85% of osteosarcoma patient apheresis samples.
• ErbB2 oncogene expression was significantly elevated (7-16 times higher than controls) in 18% of patients, correlating with tumor expression.
• Osteocalcin and Met were not useful markers due to expression in both patient and healthy donor apheresis samples.

Conclusions:

• Bone Sialoprotein (BSP) shows promise as a useful marker for detecting osteosarcoma contamination in apheresis.
• ErbB2 is a viable marker for identifying tumor contamination in apheresis for ErbB2-expressing osteosarcomas.
• These markers could aid in improving the safety and efficacy of stem cell transplantation for metastatic osteosarcoma.