All tests were two-sided and P < 0.05 was considered statistically significant. Results Patient characteristics The baseline characteristics of the study population are given in Table 1. All patients were female, with a mean ± standard deviation (SD) age of 51.6 ± 12.5 years HKI-272 molecular weight (range, 13.5 to 80.7 years) and a mean ± SD tumor size of 3.1 ± 1.8 cm (range, 0.4 to 9.5 cm). Lymph node involvement was positive in 115 patients (78.2%). According to TNM classification, 14 patients (9.5%) were stage I, 56 (38.1%) were stage II, 76 (51.7%) were stage III, and 1 (0.7%) was stage

IV. Of the 147 patients, 57 (38.8%) were positive for ER expression, 64 (43.5%) were positive for PR, 70 (47.6%) were positive for Her2, and 39 (26.5%) were positive for basal-like

features (defined as immunohistochemically negative for both SR and Her2). Of the 147 patients, 87 (59.2%) were received adjuvant chemotherapy and 95 (64.6%) were received agents targeted against estrogen receptor. Median follow-up time was 23.0 months (range, 2 to 91 months), during which 40 patients (27.2%) experienced tumor recurrence and 51 (34.7%) developed metastases. Presence of CD44+/CD24- phenotype in invasive ductal carcinoma tissue The presence of CD44 and CD24 antigens on invasive ductal carcinoma IWP-2 datasheet tissues was analyzed using double-staining immunohistochemistry. Figure 1 displays representative staining patterns of CD44 and CD24. CD44 was visible primarily as membranous permanent red staining, with only eight tumors displaying cytoplasmic and membranous staining. CD24 was visible mainly as cytoplasmic diaminobenzidine staining, with only six tumors displaying membrane diaminobenzidine staining. To determine the proportion of tumorigenic CD44+/CD24- cells within each tumor, we scanned for the presence of permanent red staining without any diaminobenzidine interference. CD44+/CD24- tumor cells were present in 103 of the 147 (70.1%) tumors, but absent from the other 44 (29.9%), with the proportion of tumor cells Selleck AZD6738 expressing this phenotype

ranging from a few to 70%, with a median proportion of 5.8%, Docetaxel and this median proportion was selected to categorize patients as CD44+/CD24- tumor cells high group and CD44+/CD24- tumor cells low group according to cutoff definition. The frequency of tumors with different proportions of CD44+/CD24- tumor cells is presented in Table 2. The proportions of CD44+/CD24- tumor cells in clinical specimens correlated significantly with lymph node involvement (P = 0.026) and PR expression (P = 0.038). Higher proportions of CD44+/CD24- tumor cells were observed in specimens from patients with (19.20%) than without (8.66%) lymph node involvement and with (21.06%) than without (13.09%) PR expression.