demonstrated via multiplex immunofluorescence that within the same tumor, NE subpopulations (e.g., SCLC-A) specifically overexpress proteins such as INSM1 and ASCL1, while adjacent non-NE subpopulations (e.g., SCLC-P) are enriched with POU2F3 and Vimentin. Here, INSM1 is linked to small cell lung carcinoma.