CEACAM5 and cancer: In terms of OS, compared to the normal-level group, elevated serum CEA was associated with an 88% increased risk of OS in MA patients (HR ═ 1.88, 95% confidence interval (CI) ═ 1.71–2.06, P < 0.001); in SRCC patients, elevated serum CEA was associated with a 44% increased risk of OS (HR ═ 1.44, 95% CI ═ 1.16–1.79, P < 0.001); however, in CA patients, elevated serum CEA was associated with an even greater risk of OS (HR ═ 2.64, 95% CI ═ 2.57–2.72, P < 0.001).