KRT19 and metastatic malignant neoplasm in the lymph nodes: In peritoneal fluid, significantly higher CK19 values were observed in patients with serosal infiltration (medians: 100 copies/μL vs. 415.7 copies/μL; p = 0.0335) and lymph node metastases (medians: 2.48 copies/μL vs. 334.8 copies/μL).