NF1 and neoplasm: In a study on embryonal rhabdomyosarcoma, loss of NF1 occurred in 35%(9/26) of tumours (heterozygous or homozygous deletion of NF1 or heterozygous chromosomal loss), and were mutually exclusive with Ras mutations, suggesting NF1 loss as an alternative and potentially common driver of Ras activation in this major subtype of soft tissue sarcoma in young children [140].