Expression of insulin-like growth factor II by a gastric carcinoma associated with hypoglycaemia.

A gastric cancer with liver metastases was associated with low morning levels of plasma glucose (24 mg/dl), insulin (< 2.5 microU/ml) and growth hormone (0.23 ng/ml). Primary and metastatic tumour tissue stained positively with anti-insulin-like growth factor II (IGF-II) monoclonal antibody. Western immunoblot analysis revealed a high molecular weight IGF-II in the serum: 15 kDa (normal: 7.5 kDa). Postmortem reverse transcription polymerase chain reaction on mRNA from both sites revealed 471 base pairs size cDNA encoding prepro-IGF-II. These results suggest that the gastric carcinoma encoded, expressed, and secreted IGF-II, probably causing the extrapancreatic tumour hypoglycaemia.