The distribution of IGF2 and IMP3 in osteosarcoma and its relationship with angiogenesis

The aim of this study was to investigate the expression patterns of IGF2 and IMP3 in osteosarcoma as well as its relationship with angiogenesis in the tumor. IGF2 and IMP3 expression was detected by immunohistochemical staining in the serial sections of the osteosarcoma. The impacts of IGF2 and IMP3 expression patterns on tumor angiogenesis were evaluated by statistics. The IGF2 and IMP3 staining had different expression patterns in different osteosarcoma. Twelve out of the sixty-four cases of conventional osteosarcoma showed nuclear staining patterns, and twenty-nine showed cytoplasmic staining of IGF2 and IMP3 simultaneously. On the other hand, fourteen cases showed nuclear IGF2 staining but cytoplasmic IMP3 expression, and nine cases showed nuclear IMP3 staining and cytoplasmic IGF2 expression. Twenty-eight out of forty-seven cases of parosteal osteosarcoma showed nuclear IGF2 and IMP3 expression, nine showed cytoplasmic IGF2 and IMP3 expression simultaneously. Seven out of forty-seven cases of parosteal osteosarcoma expressed IGF2 with nuclear staining but expressed IMP3 with cytoplasmic staining. Meanwhile, three cases expressed IGF2 with cytoplasmic staining but expressed IMP3 with nuclear staining. Similar to the parosteal osteosarcoma, the periosteal osteosarcoma expressed IGF2 and IMP3 mainly with nuclear staining simultaneously, forty out of fifty-five cases of periosteal osteosarcoma did that. Five out of fifty-five cases expressed IGF2 and IMP3 with cytoplasmic staining at the same time. Four cases showed nuclear IGF2 staining and cytoplasmic IMP3 staining. In the parosteal and periosteal osteosarcoma, there was no significant difference in IGF and IMP3 expression patterns (P = 0.216). However, compared with conventional osteosarcoma, the parosteal and periosteal osteosarcoma showed significant difference in IMP3 and IGF2 expression (P = 0.016, P = 0.023). IGF2 and IMP3 expression patterns were positive correlation in the different osteosarcoma (r = 0.1021, P = 0.032). The Microvessel density (MVD) in osteosarcoma with IGF2 and IMP3 cytoplasmic staining was more than that with nuclear expression of IGF2 and IMP3, and the difference was significant (P = 0.024). Moreover, the conventional osteosarcoma with cytoplasmic IGF and IMP3 showed more MVD than parosteal and periosteal osteosarcoma with cytoplasmic IGF and IMP3, and the difference was significant (P = 0.035). IGF2 and IMP3 had different expression patterns, which might be associated with angiogenesis. However, cytoplasmic and nuclear expression of IGF2 and IMP3 might play different roles in the angiogenesis of osteosarcoma.