The content of calmodulin in chondrosarcomas was notably lower in patients with early relapses or generalized tumor process in comparison with patients without postoperation relapses. The mean level of calmodulin in chondrosarcomas virtually did not depend on patient's sex and age and tumor location in bones. There was a tendency to an inverse correlation between calmodulin level in chondrosarcoma and the degree of tumor differentiation. The highest level of calmodulin was detected in the cytosolic fraction of chondrosarcomas containing no estrogen and androgen receptors. Key Words: calmodulin; chondrosarcoma; steroid receptorsMultiple effects of hormones, polypeptide growth factors, and other bioactive substance modifying bone tumor growth are realized through intercellular and intracellular mediators [2,6]. One of such modulators is calmodulin (CM), a universal messenger of Ca 2+ effects in the cell [5]. CM participates in transmission of apoptotic signal in cells, in particular it activates DAP-kinase responsible for changes in cytoskeleton during apoptosis [5]. CM mediates signal of tumor necrosis factor4x by activating CM-dependent type 2 kinase responsible for DNA fragmentation during apoptosis [10]. Numerous functions of CM are regulated by many factors, and structural changes in this protein caused by various mutations modify its activity [4].We previously showed that high concentration of CM in osteogenic sarcoma (above than 6000 ng/mg) is associated with low incidence of metastases during the first 5 years of observation.In this study we measured the content of CM in chondrosarcoma (CS) homogenates and investigated the relationship between CM concentration in the tumor and MATERIALS AND METHODSThirty patients (16 men and 14 women) aged 16-70 years with CS in tubular bones (n=20) and flat bones (n=10) were examined.The morphological variants of CS were as follows: (24.1%) with the first (n--7, 24.1%), second (n--12, 41.4%) and third CS of typical histological structure with the first degree of differentiation, 12 cases (41.4%) with the second degree of differentiation, 4 cases (13.8%) with the third degree of differentiation and mesenchymal CS (n=4, 13.8%) and 3 cases with dedifferentiated CS.Calmodulin in tumor homogenates was measured by radioimmunoassay using Amersham kits.The results were processed using standard statistical software for medical data. RESULTSThe content of CM varied from 1114 to 8235 ng/mg total protein. The mean level of tumor CM in men was

Estradiol-17~ receptors were detected in the cytosolic fraction of the majority of bone chondrosarcomas by protamine sulfate sedimentation of the hormone-receptor complex. The absolute number of receptors in tumors was higher in men than in women, but chondrosarcomas with estradiol-17[~ receptors more often occurred in women. The highest level of receptors was revealed in highly differentiated chondrosarcomas. No relationships between tumor location, size, type of the process, and the number of receptors was detected. We can state with assurance that the absence of estradiol-1713 receptors in chondrosarcomas in women is a favorable prognostic sign with regard to metastases or local tumor relapses.