Among the genes included in the 16-gene panel test, which exhibit the highest mutation frequency in type I and type II EC tumor tissues (PTEN, PIK3CA, PIK3R1, CTNNB1, ARID1A, ARID5B, KRAS, FGFR2, KMT2D, NOTCH1, CTCF, TP53, ARHGAP35, KDR, NF1, and FBXW7), none of the patients with EIN exhibited mutation sites that were consistent with those in the tumor tissue. This evidence concerns the gene PIK3R1 and neoplasm.