Abstract 224P
Background
Pulmonary carcinoids (PCs), including atypical carcinoids (ACs) and typical carcinoids (TCs), are a rare type of lung cancer with low or moderate malignancy. The genomic and immune features of PCs are poorly understood worldwide.
Methods
A total of 126 PC patients (ACs = 44, TCs = 82) were included in this study. Next-generation sequencing with a 578-gene panel was performed on 90 patients, and the tumor mutation burden (TMB) was further calculated. Moreover, immunohistochemistry staining of PD-L1 (n = 108) and CD8 (n = 94) was performed to explore the characteristics of the tumor microenvironment in PCs.
Results
The most commonly altered genes in PCs included EGFR (n = 16, 18%), KMT2C (n = 11, 12%), LRP1B (n = 10, 11%), MEN1 (n = 10, 11%) and NOTCH2 (n = 9, 10%). Compared to sequencing data from non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC), MEN1, GATA2, MST1, and IDH1 were the specific altered genes in PCs. The genetic alteration of TP53, ARID1A, and CUL3 occurred more frequently in ACs in comparison with TCs in further research. However, TMB, PD-L1 expression, and CD8+ infiltration, were all low and exhibited no difference between ACs and TCs.
Conclusions
Our study indicated, for the first time, the genetic landscape and immune features of Chinese PCs. We identified EGFR mutation (including 21L858R and 19Del) and amplification in Chinese PCs, which were totally different from the previously reports of other ethnic population. Overall, our study revealed potentially important mechanisms for PCs, and may provide helpful information for developing potential therapeutic strategies for Chinese PCs.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.