CD3EAP, SMAD9, and CD244 are considered valuable tumor markers (Yin et al., 2013; Hou et al., 2017; Yu et al., 2018; Pan et al., 2020; Yin et al., 2020; Gao et al., 2021; Vaes et al., 2021; Yin et al., 2022), with CD3EAP particularly noteworthy as a tumor marker in smokers. The gene discussed is SMAD9; the disease is neoplasm.