CEACAM5 and small cell lung carcinoma: Formerly, various clinical indicators have been linked to the prognoses of LS-SCLC patients; including the gender, age, smoking status, performance status (PS), carcinoembryonic antigen (CEA), hemoglobin, alkaline phosphatase (AP), and lactate dehydrogenase (LDH) [2, 7, 8].