KRT7 and small cell lung carcinoma: In addition, thyroid transcription factor‐1 (TTF‐1), Napsin A, keratin 7, and location of tumor were noticed in ADC; obscure boundary, emphysema, tumor size, the cycle number of first line chemotherapy, obstructive pneumonia atelectasis, and pulmonary nodule in SCC; as well as number of metastatic lymph nodes in SCLC, separately.