Abstract: Objective To study the clinical significance of carcino-embryonic antigen related cellular adhesion molecule 19(CEACAM19)mRNA and the relationship between the CEACAM19 mRNA expression,estrogen receptor(ER),progestrone receptor(PR),human epidermal growth factor receptor type 2(Her-2),and carbohydrate atigen 15-3(CA15-3) among breast cancer patients.Methods Totally 130 newly pathologically diagnosed breast cancer patients aged 32-70 years were recruited at a hospital from October 2008 to October 2014;52 metastatic lymph node and 130 primary breast cancer tissue specimens were collected from the patients for the detection of CEACAM19 mRNA expression with real-time PCR and the expressions of ER,PR,Her-2,CA15-3 were also measured simultaneously for most of the patients.Results The average expression of CEACAM19 mRNA in 52 metastatic lymph nodes was significantly higher than that in primary breast cancer tissues(0.788±0.87 vs.0.431±0.381,t=-3.289;P<0.05).Of the 115 patients with ER detection,80 were ER-positive;the ER-positive patients had a significantly lower proportion of high CEACAM19 mRNA expression(42.5%,34/80) compared to that of the ER-negative patients(68.6%,24/35)(P<0.05).No significant correlations were observed between the expression of CEACAM19 mRNA and detection results of PR,Her-2,and CA15-3.Conclusion CEACAM19 mRNA expression correlates with ER expression among breast cancer patients.