The present invention relates generally to a method of modulating EGFR-mediated cellular functional activity and agents useful for same. More particularly, the present invention relates to a method of modulating agonist induced EGFR-mediated cellular proliferation by modulating upstream intracellular sphingosine kinase signalling. The method of the invention is useful, inter alia, in the treatment and/or prophylaxis of conditions characterised by aberrant EGFR-mediated cellular functioning, in particular aberrant EGFR-mediated cellular proliferation.