To assess the frequency of PIK3CA gene mutations in BP-NETs we sequenced genomic DNA isolated from formalin-fixed and paraffin-embedded tissues in a large series of lung neuroendocrine tumours, including 75 low-grade TCs, 23 intermediate-grade ACs, 17 high-grade LCNECs and 75 high-grade SCLCs. The gene discussed is PIK3CA; the disease is lung neuroendocrine neoplasm.