Fig. 1: Histological morphology and mutation analysis results of NENs.

A Low-grade of NEN (H&E, Nottingham grade 2). IHC of NEN showing diffuse, uniform immunoreactivity of CgA B and Syn C. D Mutation spectrum analysis showing that the most frequent mutation type in the NENs was C > T/G > A, followed by T > C/A > G, and mutation type with the lowest frequency was T > A/A > T. Each row in the figure represents a sample, and each column represents a mutation type. The darker the mutation type, the higher proportion of the sample. E Proportion of each mutation feature in different samples. Nonnegative matrix factorization (NMF) cluster analyses revealed three different mutation signatures. The Y-axis indicates the proportion of acquired mutation signatures. Signature B was found to be identical to COSMIC mutation feature 2 with a cosine similarity greater than 0.9, and it was found in 70.6% (12/17) of the NENs in this study. F Frequency mutation gene analysis showing that the most frequently mutated genes in NENs were KMT2C (3/17, 17.6%), ACE (2/17, 11.8%), ANKRD18B (2/17, 11.8%), and CACNA1B (2/17, 11.8%). The X-axis on the bottom reflects frequency mutations, the X-axis on the top reflects the gene name, and the Y-axis reflects the sample name. The different colors in the map represent different types of mutations. This figure shows only some genes with high mutation frequencies, and the full list is shown in Supplementary Table 3.