Detection of Circulating Tumor Cell Subpopulations in Patients with Head and Neck Squamous Cell Carcinoma (HNSCC)

Abstract

BackgroundSince image based diagnostic tools fail to detect early metastasis in head and neck squamous cell carcinoma (HNSCC) it is crucial to develop minimal invasive diagnostic methods. A promising approach is to identify and characterize circulating tumor cells (CTC) in the peripheral blood of HNSCC patients. In this pilot study, we assessed which non-hematopoietic cell types are identifiable and whether their numbers differ in pre- and postoperative blood samples.Methods20 ml citrated peripheral blood was taken from 10 HNSCC patients before and after curative resection. CTC were enriched using density gradient centrifugation. CTC presence was verified by multi-immunofluorescence staining against cytokeratin (CK; epithelial), N-cadherin (mesenchymal); CD133 (stem-cell), CD45 (hematopoietic) and DAPI (nucleus). Individual cell type profiles were analyzed.ResultsWe were able to detect cells with epithelial properties like CK+/N-cadherin−/CD45− and CK+/CD133−/CD45− as well as cells with mesenchymal features such as N-cadherin+/CK−/CD45− and cells with both characteristics like N-cadherin+/CK+/CD45−. We also observed cells showing stem cell-like features like CD133+/CK−/CD45− and cells with both epithelial and stem cell-like features such as CD133+/CK+/CD45−. The number of CK positive cells (p = 0.002), N-cadherin positive cells (p = 0.002) and CD133 positive cells (p = 0.01) decreased significantly after resection. Kaplan-Meier test showed that the survival was significantly shorter when N-cadherin+ cells were present after resection (p = 0.04; 474 vs. 235 days; [HR] = 3.1).ConclusionsThis is - to the best of our knowledge- the first pilot study identifying different CTC populations in peripheral blood of HNSCC patients and showing that these individual cell type profiles may have distinct clinical implications.

Cell line dependent expression of EpCAM influences the detection of circulating tumor cells with CellSearch

“…This contributes to the great variation in detection levels of CTCs in HNSCC depending on method . Earlier studies have shown that there is a negative correlation between increased number of CTCs and survival but they do not add prognostic or predictive value beyond what is already achieved with TNM status . Therefore, simple CTC measurements as performed so far has not proven to give any specific new information that can be used for determining the treatment in the individual case of HNSCC.…”

Recent progress with next‐generation biomarkers in muscle‐invasive bladder cancer

“…They are rare cells amongst a high number of blood cells, and require specialized means for identification . Enumeration of CTCs can be carried out with a variety of assays, including density gradient centrifugation, immunomagnetic isolation and microfluidics . Many technologies for CTC detection are based on negative selection of white blood cell surface markers (especially CD45) and positive selection of epithelial cell surface markers (especially EpCAM and cytokeratin) .…”

Wound‐healing factors can prime head and neck cancer cells to increase their tumor‐forming capacity

“…These may result in a second invasive cancer or residual cancer cells remaining in the surgical wound in unde-tectable numbers (minimal residual cancer). 2 Another possible source is circulating tumor cells, [3][4][5][6][7][8][9][10][11][12][13] introduced to the vascular system before and during surgery. From there, they are supposedly able to enter, and establish growth in, the environment provided by a healing wound, rich in epidermal growth stimuli, in analogy with the tumor self-seeding hypothesis.…”