Eighty-six percent (36/42) of primary ESFT were wild-type CDKN2A. Homozygous deletion of CDKN2A was identified in 4/42 (10%) of tumours, co-deletion of CDKN2A exon 1β in three and CDKN2B in two of these samples. The gene discussed is CDKN2A; the disease is neoplasm.