Subtype N Neuroendocrine markers and steroid receptors expression     Synaptophysin CgA TTF1 ERβ ERα PR AR     pos (%) pos (%) pos (%) pos (%) pos (%) pos (%) pos (%)   SCLC 51 48 (94%) 25 (49%) 39 (76%) 30 (59%) 0 (0%) 7(14%) 1 (2%)   LCNEC 25 23 (92%) 16 (64%) 23 (92%) 15 (60%) 0 (0%) 4 (16%) 2 (8%)   AC 32 32 (100%) 31 (96%) 15 (46%) 21 (66%) 0 (0%) 3 (9%) 1 (3%)   TC 44 44 (100%) 43 (97%) 20 (45%) 30 (68%) 2 (2%) 6 (14%) 0 (0%)   total 152 147 (96%) 115 (75%) 97 (63%) 96 (63%) 2 (1%) 20 (13%) 4 (3%)

Table 2: Immunohistochemical analysis in lung NET subtypes. Only cases with data for all markers are described. Chromogranin A (CgA); Thyroid transcription factor 1 (TTF1); Estrogen Receptor (ER); Progestern receptor (PR); Androgen receptor (AR). Small-cell lung cancer (SCLC), large-cell neuroendocrine tumors of the lung (LCNEC), atypical carcinoids (AC), typical carcinoids (TC).