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

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.

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.

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).

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.