Abstract:【Abstract】 Objective To explore the association of 21 gene recurrence score with clinical pathological characteristics and the selection of adjuvant chemotherapeutic strategy. Methods The retrospective study was performed among luminal breast cancer patients from October 2016 to April 2018. Realtime PCR was used for 21 genome detection after RNA extraction, including 16 breast cancerrelated genes and 5 reference genes. Patients were enrolled into low risk, moderate risk and high risk groups, based on the calculated RS (recurrence score). Singlefactor and logistic analysis were proceeded to investigate the correlation between RS and clinicpathological features of participants. Besides, the influence of RS level on the decision of adjuvant chemotherapy strategy was also studied. Results 162 luminal breast cancer patients were enrolled. Based on the RS score, patients were grouped into lower risk 51(1388±293, 315%), intermediate risk 80 (2242±370, 494%) and high risk groups 31 (3592±317, 161%). Singlefactor analysis indicated that tumor size (2=11528，P=0001), Ki67 (2=8273，P=0016), molecular subtype (2=8864，P=0003), CK5/6 expression (2=30915，P＜0001), and histological grade (2=19513，P＜0001) were all affected the risk of recurrence. Logistic analysis results showed the significance of tumor size (β=1175，SD=0467，Wald=6322，P=0012，OR=3238，95%CI：12968093) and histological grade (β=0671，SD=0315，Wald=4541，P=0033，OR=1957，95%CI：10553629). Besides, patients receiving adjuvant chemotherapy in intermediate/high risk groups was higher (2=37164，P＜0001)，while people receiving endocrine therapy was lower than lower group (2=100309，P＜0001). For radiotherapy treatment, patients in lower risk group prefer to accept endocrine therapy (2=11388，P=0001). Conclusion Molecular subtype and histological grade were independent factors to 21 gene recurrence score, which could provide guidance to early breast cancer patients with positive expression of estrogen receptor.
