Although difference in the usage of these pathways have been found (e.g. the use of ERK activation for stimulation of proliferation in 5T33MM cells), the 5T33MM model still allows us to investigate the in vivo effects of specific inhibitors of the signalling pathways or receptor tyrosine kinase inhibitors to inhibit IGF-1 function in vivo and in this way study the potential effects of IGF-1 inhibition on tumour growth and angiogenesis in MM. The gene discussed is NTRK1; the disease is neoplasm.