PTPN11 and neuroblastoma: First, in a tumor that presents with an average somatic mutation burden of ~3 (Hwang et al., 2018), SHP2 activating mutations are found in up to 3% of NB tumors, making it among the most common reoccurring mutations in these tumors (Bentires-Alj et al., 2004; Pugh et al., 2013).