CEACAM5 and malignant colon neoplasm: He underwent five cycles of 5-fluorouracil and oxaliplatin (FOLFOX) chemotherapy, and his cancer was stable during the follow-up period from 2018 to 2021. A year ago, his carcinoembryonic antigen (CEA) levels were elevated to 25.43 ng/ml (normal range 0–5 ng/ml) and enhanced CT of the abdomen revealed recurrence of colon cancer and multiple enlarged metastases in the right anterior superior diaphragm and left inguinal region, suggesting the progression of disease.