To explore the expression of androgen receptor (AR) in breast cancer tissue and its influencing factors.

The clinical data of 972 patients with primary breast cancer admitted to the First Affiliated Hospital of Dalian Medical University from April 2016 to November 2019 were retrospectively analyzed. According to the expression of AR, the patients were divided into AR positive group and AR negative group. The patients in AR positive group were subdivided into three groups according to the proportion of AR positive cells: low expression (>1% and ≤10%), medium expression (>10% and ≤ 50%), and high expression (>50%). χ² test was used for the comparison of the count data and rank sum test was used for the comparison of the rank data. Multivariate logistic regression analysis was used to analyze the influencing factors of AR expression.

Among 972 patients with breast cancer, the positive rate of AR was 87.7% (852/972). Histological grade, ER expression, PR expression, Ki67 expression, HER-2 expression and molecular subtype all presented a significant difference between AR positive group and AR negative group (Z=-6.089, P<0.001; χ²=153.920, P<0.001; χ²=121.064, P<0.001; χ²=4.950, P=0.026; χ²=13.645, P<0.001; Z=-9.799, P<0.001). The results of multivariate analysis showed that histological grade(grade 2 vs grade 3: OR=2.206, 95%CI: 1.302-3.740, P=0.003), ER expression (positive vs negative: OR=19.174, 95%CI: 6.150-59.777, P<0.001); PR expression (positive vs negative: OR=4.723, 95%CI: 2.070-10.777, P<0.001), HER-2 expression (positive vs negative: OR=3.807, 95%CI: 1.363-10.638, P=0.011), and molecular subtype(luminal B vs luminal A: OR=2.187, 95%CI: 1.013-4.723, P=0.046; HER-2 positive vs luminal A: OR=27.951, 95%CI: 4.051-192.870, P=0.001; triple negative vs luminal A: OR=7.889, 95%CI: 1.396-44.569, P=0.019) were independent influencing factors for AR positive expression. Among 852 AR-positive patients, 55 patients had low expression (6.5%, 55/852), 158 patients had medium expression (18.5%, 158/852), and 639 patients had high expression (75.0%, 639/852). There was a significant difference in histological grade, ER expression, PR expression and molecular subtype among the three groups (H=14.126, P=0.001; χ²=20.211, P<0.001; χ²=21.090, P<0.001; H=13.413, P=0.001). The results of pairwise comparison showed that the proportion of patients with histological grade 2, ER positive rate and PR positive rate in patients with high expression of AR were significantly higher than those in patients with low or medium expression of AR(P=0.002, 0.009; χ²=5.898, 17.891, P=0.015, P<0.001; χ²=20.157, 6.827, P<0.001, P=0.009), respectively, while the proportion of patients with histological grade 3 and triple negative breast cancer was significantly lower(P=0.003, 0.009; P=0.028, 0.012).

The breast cancer patients show high expression of AR. Patients with a higher proportion of AR-positive cells have lower histologic grade and higher ER/PR expression rates.