The frequency of positive PD-L1 expression in T-NEN is comparable with the frequency in 159 pulmonary NENs (72/159, 45%) reported by Wang et al (23), and is relatively higher than the frequency in 106 pancreatic NETs (26/106, 25%) reported by Mehnert et al (7), or in 57 GEP-NENs (16/57, 28%) reported by Cavalcanti et al (28). Here, CD274 is linked to pancreatic neuroendocrine tumor.