Relationship of CD44+CD24-/low breast cancer stem cells and axillary lymph node metastasis

Background: Axillary node staging plays an important role in the prognostic evaluation and planning of adjuvant treatment. Breast cancer stem cells, identified on the basis of CD44(+)CD24(-/low) expression, are associated with metastases and drug resistance. It is therefore important to investigate the proportion of CD44(+)CD24(-/low) breast cancer stem cells for the diagnosis of metastases in axillary nodes. Methods: Thirty-two ipsilateral axillary lymph nodes were collected from patients diagnosed with invasive breast cancer. Each lymph node (LN) was divided into two equals - one was examined by H&E staining, while the other was made into a single cell suspension to study the content of CD44(+)CD24(-/low) cells by flow cytometry (FCM). The relationship was investigated between the content of CD44(+)CD24(-/low) cells and metastases in axillary nodes which were confirmed by histology. Associations were tested using the chi-square test (linear-by-linear association), and the significance level was set at a value of p < 0.05. Results: In the 32 axillary nodes, the level of CD44(+)CD24(-/low) cells was determined to be between 0 and 18.4%: there was no presence of CD44+CD24-/low cells in 9 LNs, of which 2 had confirmed metastasis; there were less than 10% CD44+CD24-/low cells in 12 LNs, of which 6 had confirmed metastasis; and there were more than 10% CD44+CD24-/low cells in 11 LNs, of which 9 had confirmed metastasis. A higher percentage of detected CD44(+)CD24(-/low) cells was significantly associated with more confirmed LN metastases (p = 0.009). Conclusions: CD44(+)CD24(-/low) breast cancer stem cells might help clinicians to determine the presence of LN metastases. However, its prognostic value remains unclear, while histological diagnosis is still the gold standard.