CEACAM5 and ovarian cancer: Tumor biomarker CA125 can be used as a major marker for ovarian cancer [27], and serum tumor markers, carcinoembryonic antigen (CEA), cancer antigen 125 (CA125), and cytokeratin 19 segments (CYFRA21-1) can all be used to monitor the response of patients with NSCLC to chemotherapy or targeted therapy [28].