Objective To explore the relationship between serum levels of glycoprotein fibroglycan(SRGN)and secretory CD146(sCD146)and clinicopathological characteristics and prognosis in elderly pa-tients with breast cancer(BC).Methods A total of 128 elderly BC patients treated in the hospital from April 2019 to April 2021 were retrospectively selected as the BC group,and another 70 healthy elderly women were selected as the control group.The serum SRGN and sCD146 levels in BC group and control group,and patients with different clinical and pathological characteristics in BC group were compared.Kaplan-Meier curve and COX regression were used to analyze the effect of serum levels of SRGN and sCD146 on the prognosis of eld-erly BC patients.Receiver operating characteristic curve was used to analyze the predictive value of serum lev-els of SRGN and sCD146 for the prognosis of elderly BC patients.Results The levels of serum SRGN and sCD146 were(13.17±3.35)μg/L,(118.23±20.51)ng/L in the BC group,which were higher than(2.52±0.41)μg/L,(20.03±4.16)ng/L in the control group(t=26.460,39.572,both P<0.001).Compared with elderly BC patients with TNM stage Ⅰ-Ⅱ and histological grade Ⅰ-Ⅱ,serum SRGN and sCD146 levels in elderly BC patients with TNM stage Ⅲ and histological grade Ⅲ were higher(P<0.05).The 3-year progres-sion free survival rates in SRGN high and low expression groups were 66.13%(41/62)and 92.42%(61/66),respectively,and the 3-year progression free survival rate in SRGN high expression group was lower than that in SRGN low expression group(Log Rank χ2=14.180,P<0.001).The 3-year progression free survival rates in sCD146 high and low expression groups were 68.85%(42/61)and 89.55%(60/67),respectively,and the 3-year progression free survival rate in sCD146 high expression group was lower than that in sCD146 low ex-pression group(Log Rank χ2=8.614,P=0.003).TNM stage Ⅲ,histological grade Ⅲ,serum SRGN and sCD146 were risk factors for the poor prognosis of elderly BC patients.The area under the curve(AUC)of the combination of serum SRGN and sCD146 for predicting the prognosis of elderly BC patients was 0.850,which was larger than that of SRGN(AUC=0.798)and sCD146(AUC=0.771)alone(Z=2.057,2.217,P=0.042,0.029).Conclusion Serum levels of SRGN and sCD146 are elevated in elderly BC patients,and both are in-volved in the disease progression of BC.The combination of the two factors has high predictive value for the prognosis of elderly BC patients.