PurposeIn this study, we aimed to explore the potential significance of AR expression in HER2-positive breast cancer patients who underwent neoadjuvant targeted therapy. Specifically, we investigated the correlation between AR expression levels and pathological complete response (pCR) rates. Our objective was to determine whether there were significant differences in pCR rates among HER2-positive breast cancer patients with different levels of AR expression.MethodsWe conducted a retrospective analysis of 258 HER-2 positive breast cancer patients who underwent neoadjuvant dual-blocked standard therapy (following the NCCN Guideline 2021) at three breast cancer centers in southwest China. We analyzed the clinicopathological features and pCR rates of these patients. The cut-off value for AR expression level was calculated as the median value of 70%. We used the chi-square test to investigate the correlation between AR expression level and pCR rate, as well as other clinicopathological features.ResultsOut of the 258 patients analyzed, 154 (59.69%) achieved pCR. Based on the cut-off value of 70%, AR expression level was classified as low (AR <= 70%) or high (AR > 70%) expression. Our analysis revealed a significant correlation between AR expression level and pCR rate in HER2-positive breast cancer patients (P = 0.031). We also found a significant association between pCR rate and clinical stage (P = 0.033) and chemotherapy regimen (P = 0.034).Furthermore, subgroup analyses showed that the pCR rate was higher in patients with high AR expression levels compared to those with low AR expression levels. Additionally, we observed that patients with an ER/AR ratio of less than 1 had a higher pCR rate than those with an ER/AR ratio greater than 1 (P = 0.038).ConclusionOur study findings suggest that HER2-positive breast cancer patients with high AR expression levels may achieve higher pCR rates when treated with neoadjuvant dual-blocked therapy. Overall, our results support the idea that AR expression levels have a significant correlation with pCR rates in HER2-positive breast cancer patients receiving this particular form of treatment.