Insulin-like growth factor 1 and its binding protein-2 in tumor and peritumoral tissues as important factors involved in recurrence of soft tissue sarcomas in older men.

Abstract

e23556 Background: The system of insulin-like growth factors (IGF) is involved in the pathogenesis of many malignant tumors. At the same time, the specificity of this system in recurrent soft tissue sarcomas is unknown. The purpose of this study was to analyze the IGF system in tumors and their peritumoral areas in men with recurrent soft tissue sarcomas. Methods: The study included 26 men aged 57.8±6.2 years with primary (n = 12, group 1, controls) and recurrent (n = 14, group 2, main group) soft tissue sarcoma of the extremities, T2bN0M0. Grade 1 tumors were diagnosed in 6 patients of group 1 and in 7 patients of group 2, while the other patients had G3 or G4 tumors. 95% of tumors were liposarcomas. All patients of group 2 had previously underwent surgical and radiation treatment for primary sarcomas and their relapses (up to 2 episodes), with the last surgery more than 1 year ago. Levels of the IGF system components were determined in tumor (T) and peritumoral (PT) tissues by ELISA, and ratios of IGF(T)/IGF(PT) were calculated. Results: Levels of the IGF system components in patients of group 1 were similar in T and PT. In group 2, levels of IGF1 and IGFВР2 in T were respectively 2.2 and 1.6 times (p < 0.05) lower than in PT, but did not differ significantly from the levels in group 1. The IGF1(T)/IGF1(PT) ratio in patients of group 2 was 1.8 times (p < 0.05) lower than in group 1. PT levels of IGF2 in group 2 depended on the tumor grade: they were 1.5 times (p < 0.05) higher in G1 than in G3-G4, while no such dependence was observed in T. Conclusions: The levels of the IGF system components in recurrent soft tissue sarcomas in older men had some peculiarities. Unlike primary sarcomas with similar levels of the studied components of the IGF system in tumors and in peritumoral tissues, recurrent tumors contained less IGF1 and IGFBP2 than the corresponding peritumoral areas. The levels of IGF2 in the peritumoral tissues of recurrent tumors depended on the tumor grade.