RB1 and small cell lung carcinoma: The prevalence of mutations in pNEC was 18% for TP53, 10% for RB1, 33% for MEN1 and 20% for DAXX, indicating that mutations in TP53 and RB1 are less common in pNEC than in SCLC, colon NEC and other types of gastrointestinal (GI)-NECs, whereas mutations in MEN1 and DAXX are more common in pNEC (Table 3).