Aim and purpose. The clinical management of osteosarcoma differs significantly from that of chondrosarcoma;. Therefore it is extremely important to diagnose these two types of bone tumour accurately. In the absence of a specific marker, differential diagnosis by histochemistry is sometimes impossible, especially between chondroblastic osteosarcoma and conventional chondrosarcoma. The aim of the study was to find an useful diagnostic marker, simple to use for distinguishes chondroblastic osteosarcoma from conventional chondrosarcoma. Method. We analysed 165 bone sarcomas by immunohistochemical staining of tissue microarrays for expression of the galectin-1 (GAL1) lectin and by Western Blot experiments. Results. We found that GAL1 was abundant in normal human osteoblasts from benign proliferations and in osteosarcomas, including chondroblastic osteosarcomas, but not in chondrosarcomas. There was a highly significant statistical difference in the percentage of stained cells (p<10-4) and in the staining intensity (p<10-3) of chondroblastic osteosarcomas compared to conventional chondrosarcomas. This discriminatory potential of GAL1 staining for osteosarcoma-derived tumours was confirmed by western blotting. We propose a
