Serum Cytokeratin 19 Fragment, CK19-2G2, as a Newly Identified Biomarker for Lung Cancer

BACKGROUND: CK19-2G2, a new fragment of cytokeratin 19, is a potential tumor marker for diagnosing lung cancer. The preoperative level of serum CK19-2G2 has been demonstrated to be associated with tumor metastasis and survival of breast cancer patients. This study investigated the postoperative dynamic changes in serum CK19-2G2 levels and its clinical significance in lung cancer patients. MATERIALS AND METHODS: Preoperative serum CK19-2G2 levels were measured in 630 lung cancer patients and were compared with individuals with benign pulmonary diseases (n = 134) and healthy volunteers (n = 263). In 352 cases, the patients underwent surgery. In these patients, in addition to preoperative assays, serum CK19-2G2 was also monitored at 1 week and 1 month after the operation. RESULTS: The preoperative baseline levels of serum CK19-2G2 was significantly higher in lung cancer patients than patients with benign diseases and healthy controls (P<0.001). The postoperative levels of CK19-2G2 declined significantly within 1 week after tumor resection. Hereafter, a further decrease was observed in the patients who underwent palliative operations, while for the patients in the radical resection group, their CK19-2G2 levels stabilized. CONCLUSION: CK19-2G2 may be a candidate marker for diagnosing and monitoring a patient's response to lung cancer treatment. In addition, CK19-2G2 may be an indicator for micrometastases in lung cancer patients.