According to the ROC analysis, the cut-off values between the respective tumor entities for the TOP2A expression as determined by IHC were as follows: TC-AC: 1.25% (AUC = 0.896, p < 0.001, sensitivity = 0.810, 1-specificity = 0.042), AC-SCLC: 15.0% (AUC = 0.981, p < 0.001, sensitivity = 0.980, 1-specificity = 0.000), AC-LCNEC: 19.5% (AUC = 1.000, p < 0.001, sensitivity = 1.000, 1-specificity = 0.000). Here, TOP2A is linked to large cell neuroendocrine carcinoma.