Detection of putative stem cell markers, CD44/CD133, in primary and lymph node metastases in head and neck squamous cell carcinomas. A preliminary immunohistochemical and in vitro study

Objectives Investigators hypothesized that cancer stem cells (CSCs) could play a role in determining cancer progression by metastasizing to cervical lymph node (N+) and then influencing prognosis of head and neck squamous cell carcinomas (HNSCCs) patients. Design To identify CSCs in HNSCCs and their clonogenic capacity. Setting In vitro study. Participants Putative CSCs from 29 primary HNSCCs and 19 corresponding node metastases were analyzed. Main outcome measures Immunohistochemical (IHC) was performed, and CSCs' clonogenic in vitro capacity was tested; ones epithelial nature of cancer cells forming colonies was confirmed by a second IHC, fluorescence-activated cell sorting (FACS) analysis helped in counting CD44/CD133-CSCs markers percentage expression in HNSCC tumour-derived cultures. Results Immunohistochemical showed CD44 (93.1%) and CD133 (10.34%) expression; FACS-analysis showed the enrichment of CD44/CD133 cancer cells, with the highest clonogenic capacity of CD44+-subpopulation; a higher CD44 rates were documented from N+ subcultures than from original tumours (P < 0.05). Conclusions A putative cancer stem-like cell population is detectable in HNSCCs, and our findings show their in vitro clonogenic capacity by demonstrating that CD44+-cultured cells are the main population proliferating obtained by N+ HNSCC metastases, emphasizing their possible role in tumour progression.