CCND3 and Lymphatic Metastasis: Specifically, 65 (60.2%) of 108 LUAD cases with lymph node involvement exhibited CCND3 downregulation, whereas only 30 (28.6%) of 105 cases without lymphatic metastasis exhibited low CCND3 expression, indicating a significant correlation between the reduced expression of CCND3 and the presence of lymphatic metastases in patients with LUAD (χ2 = 21.535, p < 0.0001; Table S5).