['The aim of this study was to examine the correlation, if any, between the preoperative neutrophil/lymphocyte ratio (NLR) and the OncotypeDX™ 21-gene recurrence score (RS) in patients with early-stage estrogen receptor (ER)-positive breast cancer (BC).', 'We retrospectively reviewed the medical records of patients diagnosed with primary ER-positive BC who were referred for the RS assay. The correlation between the preoperative NLR and the RS was analyzed.', 'For the 242 patients with sufficient data for analysis, the median age at diagnosis was 59.5 years. The tumor size ranged from 0.50 to 5.50 cm, with a mean size of 1.8 cm; 73.2% of the tumors were < 2 cm in size. Most of the tumors (66.3%) were of grade 2; the rest was nearly equally divided between grades 1 and 3. The test results for the progesterone receptor (PR) were positive in 86.6% of the cases. Lymph node metastases were present in 22.3% of the patients. The median RS was 18 (range 0-60) and the mean NLR value was 2.11 (range 0.49-7.49). We found no significant correlation between the NLR and the RS.'] Does the preoperative neutrophil/lymphocyte ratio correlate with the 21-gene recurrence score in estrogen receptor-positive breast cancer patients?