In vivo cytokinetic effects of recombinant human growth hormone (rhGH) in patients with advanced breast carcinoma.
We have investigated the possibility of inducing a kinetic recruitment of breast cancer cells by the in vivo administration of recombinant human Growth Hormone (rhGH). Twelve patients with advanced breast cancer received rhGH i.m. for 2 days immediately before the first course of chemotherapy. The following biological parameters have been evaluated before and 24 hours after rhGH administration: tumor TLI, tumor IGF-I content, serum IGF-I concentration. The mean tumor TLI values before and after rhGH were 1.3% and 2.6% respectively; median tumor and serum IGF-I levels before rhGH were 4.64 ng/g and 63.5 ng/ml respectively; after the administration of rhGH median tumor IGF-I content was 1.8 and median serum IGF-I level was 112 ng/ml. These data suggest that, in vivo, rhGH stimulates breast cancer cell proliferation; the mitogenic stimulus is likely due to the local production of IGF-I induced by rhGH.