Abstract:

Objective To investigate the clinical value of 21-gene recurrence score（RS） in mucinous breast cancer（MBC）. Methods Totally,96 MBC patients with estrogen receptor（ER） positive and human epidermal growth factor receptor 2（HER-2） negative who underwent surgical treatment were enrolled,and the clinical data of all the patients were collected. RNA was extracted from the tumor paraffin specimens of patients. Real-time fluorescence quantitative polymerase chain reaction（PCR） was used to determine the expression of 21 genes,and 21-gene RS was calculated. According to the scores,all the patients were classified into low-risk group（<18 points）,intermediate-risk group（18-30 points）and high-risk group（>30 points）. Logistic regression was used to analyze the influence factors of 21-gene RS. Kaplan-Meier curve was used to assess disease-free survival（DFS）.Results Among the 96 patients with breast cancer,there were 23 patients（24.0%） in the low-risk group,63 patients（65.6%） in the intermediate-risk group and 10 patients（10.4%） in the high-risk group. There was statistical significance in progestin receptor（PR） expression,molecular typing and tumor size among the low-risk group,intermediate-risk group and high-risk group（P<0.05）. There was no statistical significance in age,menopausal time,staging and Ki67 expression（P>0.05）. Multivariate analysis demonstrated that PR status was independently associated with high risk based on 21-gene RS [odds ratio（OR）=7.271,95% confidence interval（CI） 0.728-3.240]. Univariate analysis found that the choice of chemotherapy was related to Ki67 expression,molecular typing,PR expression and 21-gene RS（P<0.05）．There was no correlation in age,tumor size,menopausal time,operation method and staging（P>0.05）. Multivariate analysis showed that Ki67 expression and 21-gene RS independently influenced the use of chemotherapy（P<0.05）. No statistical significance in DFS was found among MBC patients in different 21-gene RS subgroups（P>0.05）.Conclusions 21-Gene RS is related to PR status in MBC patients. 21-Gene RS does independently affect the choice of chemotherapy. However,21-gene RS is not able to predict DFS in MBC patients.

Key words: 21-Gene recurrence score, Mucinous breast cancer, Clinicopathologic characteristic, Adjuvant chemotherapy