These molecular characteristics are further stratified into four major subtypes, SCLC-A, SCLC-N, SCLC-P, and SCLC-I, based on the expression of key transcription factors such as ASCL1, NEUROD1, and POU2F3, which reflect distinct tumor behaviors and potential treatment responses [3]. Here, POU2F3 is linked to small cell lung carcinoma.