c-peptide and Retroperitoneal-Neoplasms

A man, aged 65 years, presented with frequent episodes of hypoglycemia and unconsciousness. Hypoglycemia was accompanied by undetectable serum insulin and C-peptide levels and a high serum insulin-like growth factor (IGF)-II level. He was found to have a retroperitoneal solitary fibrous tumor. He underwent successful resection of the tumor and had no hypoglycemic episodes after the operation. Immunohistochemical analysis revealed positive immunostaining for IGF-II in tumor cells. The presence of the high-molecular-weight form of IGF-II in the patient's serum was confirmed by immunoblotting, which suggests that his hypoglycemia was due to an increase in the plasma level of IGF-II secreted by the tumor.

Topics: Aged; C-Peptide; Humans; Hypoglycemia; Insulin; Insulin-Like Growth Factor II; Male; Neoplasm Proteins; Radiography; Retroperitoneal Neoplasms; Unconsciousness

Haemangiopericytoma is a rare soft tissue tumour originating from the contractile pericapillary cells. Relatively little is known about its molecular pathogenesis. To address this issue, the insulin-like growth factor family (IGFs) was analysed in 19 tumours collected from a human tumour bank network. Seven of the tumours were associated with severe hypoglycaemia. Of these, six were retroperitoneal and one was located in the leg. 3 out of the 19 tumours (15.8 per cent) were positive for insulin-like growth factor I (IGF I) mRNA and 11 were positive for IGF II mRNA (57.9 per cent). Almost 90 per cent of haemangiopericytomas expressed IGF I receptor (IGF IR) mRNA (17 out of 19), five (26.3 per cent) expressed IGF binding protein 1 (IGF BP1), three (15.8 per cent) expressed IGF BP2, and four (21 per cent) exhibited IGF BP3 mRNA. All of the 14 haemangiopericytomas examined with regard to specific receptor binding were IGF IR positive, ranging from 1.2 to 16.2 per cent. Binding was much higher in IGF I/IGF IR positive tumours (15.3+/-0. 7) than in IGF I negative/IGF IR positive tumours (5.1+/-3.3). The potential role of IGF IR as a growth promoting factor in malignant haemangiopericytoma was studied using antisense oligonucleotides and monoclonal antibody alphaIR3 that specifically inhibit IGF IR synthesis or activity. 10 microM IGF IR antisense oligonucleotides significantly inhibited the growth of haemangiopericytoma cells in culture, by around 50 per cent; monoclonal antibody against IGF IR (alphaIR3) also significantly inhibited proliferation. The data suggest that IGF IR may play an important role in the genesis and progression of malignant haemangiopericytomas.

Topics: Adult; Aged; Aged, 80 and over; Blood Glucose; C-Peptide; Cell Division; Child, Preschool; Female; Hemangiopericytoma; Humans; Hypoglycemia; Insulin; Insulin-Like Growth Factor Binding Proteins; Insulin-Like Growth Factor I; Insulin-Like Growth Factor II; Lung Neoplasms; Male; Middle Aged; Pelvic Neoplasms; Receptor, IGF Type 1; Retroperitoneal Neoplasms; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Somatomedins; Tumor Cells, Cultured