Association study of 6 candidate single-nucleotide polymorphisms (rs7921, rs7956547, rs3761243, rs11737764, rs6599400, rs1690916) was carried out in a group of patients with bone tumors of different histological structure (n=68) and control group of normal subjects (n=96). Significant associations of rs6599400 and rs1690916 polymorphisms with disease risk were detected (odds ratio 2.15 [1.06-4.24] and 0.39 [0.19-0.78], respectively). These polymorphisms were located in untranslated genome regions: polymorphism rs6599400 in the 5' region of fibroblast growth factor-3 receptor gene (FGFR3), rs1690916 in the 3' region of mouse MDM2 p53-binding protein homolog (MDM2). These data indicated a possible role of hereditary genetic factors in the formation of predisposition to bone sarcomas and confirmed previous findings according to which these genes should be regarded among the most probable factors involved in tumor development, including tumors of the bone and cartilage tissues.

Comparative enzyme immunoassay of matrix metalloproteinases (MMP-2, -7, -9) and their tissue inhibitor-1 (TIMP-1) in the sera of 26 healthy individuals and 54 patients with primary osteal tumors before therapy revealed elevated TIMP-1 levels in the patients with classical central and periosteal osteosarcomas in comparison with the control. In patients, the level of MMP-9 significantly decreased compared to that in healthy individuals, while the levels of MMP-2 and MMP-7 remained unchanged. No differences in serum levels of MMP and TIMP-1 associated with gender, age, primary osteal tumor location and size were detected. Overall 3-year survival of patients with classical central osteosarcoma with serum level of MMP-9 below its median was higher than that of patients with MMP-9 level equal to above the median (90.9 ± 8.7 and 50.8 ± 23%, respectively).

Serum levels of endostatin, placental growth factor (PlGF), and fibroblast growth factors-1 and -2 (FGF-1 and FGF-2) were measured in 58 patients with primary osteosarcomas before therapy and in 21 healthy subjects. The incidence of serum FGF-1 in bone tumors was 2.5 times higher than in healthy individuals (p=0.004); significant levels of FGF-2, PlGF, and endostatin were detected in all examined subjects. The mean serum level of endostatin in healthy individuals was significantly lower than in the total group of patients with bone tumors (p=0.005). The level of FGF-1 in osteosarcomas was significantly higher than in chondrosarcomas (p<0.05). No appreciable differences in FGF-2 levels were detected in patients with tumors of different histological structure. The mean serum content of PlGF was virtually the same in healthy individuals and patients with bone tumors. A significant relationship between serum PlGF level and maximum tumor size (p=0.008) was detected in osteosarcoma. No relationships between the levels of FGF-1, FGF-2, PlGF, and endostatin were detected in healthy subjects and patients with primary tumors of the bones. Differences in 3-year overall survival values of patients with bone sarcomas with different initial serum levels of FGF-1 and endostatin were detected.