Objective To investigate the expressions of transmembrane protein 8(Tspan8)and integrin α5(ITGA5)in breast cancer and their relationship with clinicopathological features and prognosis.Methods A total of 136 breast cancer patients admitted to the hospital from April 2018 to April 2020 were enrolled in the study.Breast cancer tissue samples and corresponding paracancerous tissue samples were collected.The ex-pressions of Tspan8 and ITGA5 in breast cancer tissues and corresponding adjacent tissues were detected by immunohistochemistry.The relationship between the expressions of Tspan8 and ITGA5 and the clinicopatho-logical characteristics of breast cancer patients was analyzed.The discharged breast cancer patients were fol-lowed up for 36 months,and the survival status of the patients was recorded.The 3-year survival rate of breast cancer patients with different clinicopathological characteristics was compared.Multivariate Cox regression was used to analyze the influencing factors of axillary lymph node metastasis in breast cancer patients.Results The positive expression rates of Tspan8 and ITGA5 in breast cancer tissues were higher than those in adjacent tissues(P＜0.05).The positive expression rates of Tspan8 and ITGA5 in breast cancer patients with poor differentiation,tumor maximum diameter ≥3 cm,TNM stage Ⅲ-Ⅳ,axillary lymph node metastasis and other molecular subtypes were higher than those in moderate/well differentiation,tumor maximum diam-eter＜3 cm,TNM stage Ⅰ-Ⅱ,no axillary lymph node metastasis and triple negative subtype(P＜0.05).The 3-year survival rate of patients with positive expression of Tspan8 and ITGA5 was significantly lower than that of patients with negative expression of Tspan8 and ITGA5(P＜0.05).The 3-year survival rate of patients with poor differentiation,TNM stage Ⅲ-Ⅳ,axillary lymph node metastasis,other molecular sub-types and positive expressions of Tspan8 and ITGA5 were lower than those of patients with moderate/high differentiation,TNM stage Ⅰ-Ⅱ,no axillary lymph node metastasis,triple negative subtype and negative ex-pressions of Tspan8 and ITGA5(P＜0.05).TNM stage Ⅲ-Ⅳ(HR=2.289,95％CI:1.519-3.447),other molecular subtypes(HR=2.622,95％CI:1.744-3.942),Tspan8 positive expression(HR=3.622,95％CI:2.159-6.077)and ITGA5 positive expression(HR=3.142,95％CI:2.022-4.884)were risk factors for ax-illary lymph node metastasis in breast cancer patients(P＜0.05).Conclusion Tspan8 and ITGA5 are highly expressed in breast cancer patients,which are related to the clinicopathological characteristics and prognosis of patients.