C-peptide does not parallel increases of serum levels of substances immunologically cross-reactive with insulin in non-Hodgkin's lymphoma patients

In 28 of 45 patients suffering from non-Hodgkin's lymphoma, the blood levels of substances detectable by the insulin-specific radioimmunoassay were supranormal, while the C-peptide levels were almost normal or even low. Such a ratio of these substances was also found in a diabetic non-Hodgkin's lymphoma patient. Two sera with the highest concentrations of these substances were investigated by gel filtration. In one case, the insulin cross-reactive material was eluted at the position of the insulin marker; in the other serum, its molecular mass was approximately 120,000.