CEACAM5 and Pleural effusion: Curiously, clinical factors including pleural effusion; tumor size; tumor biomarkers CEA, CA125, and CA153; chemotherapy cycles; and brain metastases did not significantly affect survival in these patients and were therefore not considered risk factors (p=0.686, p=0.5509, p=0.219, p=0.809, p=0.445, p=0.344, and p=0.991, respectively; Figure 3D, Table 2).