Galectin-1 (GAL-1) expression is a useful tool to differentiate between small cell osteosarcoma and Ewing sarcoma

Area of Science:

• Oncology
• Pathology
• Biomarker Research

Background:

• Galectin-1 (GAL-1) is known to be expressed in osteosarcomas.
• Its diagnostic utility has been established for differentiating chondroblastic osteosarcomas from conventional chondrosarcomas.
• GAL-1 expression has not been previously evaluated in the Ewing sarcoma family of tumors (ESFTs).

Purpose of the Study:

• To investigate and compare Galectin-1 (GAL-1) expression across different bone tumor types, specifically osteosarcomas, chondrosarcomas, and genetically confirmed ESFTs.
• To assess the potential of GAL-1 as a diagnostic marker for distinguishing between these tumor categories.
• To determine if GAL-1 expression correlates with histological subtypes or clinical outcomes in ESFTs.

Main Methods:

• Immunohistochemistry was employed to analyze GAL-1 expression.
• A tissue microarray was utilized, comprising samples from 43 osteosarcomas, 23 chondrosarcomas, and 217 ESFTs.
• Expression levels were quantified and correlated with tumor type, subtype, and clinical data.

Main Results:

• GAL-1 was expressed in 78% of osteosarcomas, 33% of chondrosarcomas, and only 8% of ESFTs.
• Osteoblastic and small cell osteosarcomas showed high GAL-1 expression, while it was mainly observed in high-grade chondrosarcomas.
• GAL-1 positivity in ESFTs was rare (8%) and not linked to histological subtype or prognosis.

Conclusions:

• GAL-1 expression is a valuable tool for differentiating osteosarcomas, particularly osteoblastic and small cell subtypes, from ESFTs.
• While GAL-1 can help distinguish chondroblastic osteosarcomas from conventional chondrosarcomas, histopathology remains crucial due to exceptions.
• GAL-1 immunoexpression does not serve as a prognostic indicator in ESFTs.