Activated Ha-ras was introduced to HMF3A cells. HMF3A cells are conditionally immortalised human mammary fibroblasts. They undergo co-ordinated senescence upon inactivation of LT antigen, when cultured at 39C. The introduction of Ras did not prevent this but affected the molecular profile. Keywords = Senescence Keywords = fibroblast Keywords = Ras Keywords = immortalization Keywords = transformation