Half (50%) of the clinicians examining the cats with IGF-1< 1000 ng/ml did not suspect presence of HS (answering ‘no’), whereas a quarter (24%) of clinicians examining the cats with IGF-1>1000ng/ml strongly suspected presence of HS; the remainder was non-committal (answering ‘maybe’). The gene discussed is IGF1; the disease is histiocytic sarcoma.