[Positive feedback mechanisms by which immunoproliferative tumors stimulate their own growth].
Based on clinical findings of patients with some proliferative tumors and experimental data, a hypothesis of positive feedback mechanism by which tumor stimulates its own growth has been formulated. In some patients with Hodgkin's disease and non-Hodgkin's lymphomas, i.e. leukemias, the high levels of substances immunologically cross reactive with insulin (SICRI), low glycemic values and increased values of growth hormone were found in the blood. These findings were in correlation with the status and stages of the disease. In a more advanced stage of the disease, the concentration of insulin-like substances was higher and glucose levels were lower in patients in remission. The high correlation was found between the increased SICRI levels of insulin-like substances showed faster growth. It is certain that some tumor cells excrete these substances. In mice with melanomas, high concentrations of these substances, growth hormone and low glucose levels were found in the blood. On the basis of these findings a hypothesis was formulated about positive feedback mechanism by which tumors stimulates their own growth. Tumor excretes SICRI which decreases glucose concentration in the blood. Hypoglycemia is a stimulation for the pituitary to release growth hormone into the blood. This hormone probably stimulates protein synthesis and replication of tumor cells contributing to increased SICRI excretion, etc. The final results of this positive feedback mechanism is faster growth of tumor and death of host.
D000293:Adolescent; D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D003429:Cross Reactions; D005246:Feedback; D013006:Growth Hormone / Q000097:blood; D006689:Hodgkin Disease / Q000097:blood / Q000276:immunology / Q000503:physiopathology*; D006801:Humans; D007328:Insulin / Q000276:immunology*; D008223:Lymphoma / Q000097:blood / Q000276:immunology / Q000503:physiopathology; D008875:Middle Aged
D001786:Blood Glucose; D007328:Insulin; D013006:Growth Hormone
O mehanizmu pozitivne povratne sprege kojom imunoproliferativni tumori podsticu vlastiti rast.