[Formula: see text] 2 [Formula: see text] 1 may be a potential marker for cancer stem cell in laryngeal squamous cell carcinoma

Cancer stem cells (CSCs) have the ability to dictate tumor initiation, recurrence, and metastasis. Here, we examined the expression of a [Formula: see text] 2 [Formula: see text] 1 [Formula: see text] in laryngeal cancer tissues and further determined the effect of [Formula: see text] 2 [Formula: see text] 1 on the migratory ability and tumorigenicity of laryngeal cancer cells. Immunofluorescence staining revealed that [Formula: see text] 2 [Formula: see text] 1 was positive in 13 (13/16, 81.25%) cases in laryngeal squamous cell carcinoma (LSCC) tissues, 7 (7/16, 43.75%) cases in paracancerous tissues and only 2 (2/16, 12.5%) cases in normal tumor tissues. Our quantitative RT-PCR assays further showed that [Formula: see text] 2 [Formula: see text] 1 [Formula: see text] LSCC cells expressed significantly higher levels of stem cell-associated genes and drug efflux and resistance genes versus [Formula: see text] 2 [Formula: see text] 1 [Formula: see text] cells. Sphere-forming assays demonstrated higher sphere-forming efficiency in the [Formula: see text] 2 [Formula: see text] 1 [Formula: see text] versus [Formula: see text] 2 [Formula: see text] 1 [Formula: see text] subpopulation. Our Matrigel assays showed that [Formula: see text] 2 [Formula: see text] 1 [Formula: see text] cells exhibited significantly greater invasive and migratory ability than [Formula: see text] 2 [Formula: see text] 1 [Formula: see text] cells. Furthermore, the percentage of purified [Formula: see text] 2 [Formula: see text] 1 [Formula: see text] in TU686 and TU212 cells treated cisplatin or paclitaxel was significantly higher than that of the control group. Tumor xenograft assays revealed that the tumorigenicity of [Formula: see text] 2 [Formula: see text] 1 [Formula: see text] cells was much higher than [Formula: see text] 2 [Formula: see text] 1 [Formula: see text] cells. In conclusion, a [Formula: see text] 2 [Formula: see text] 1 [Formula: see text] subpopulation with CSC-like property was present in laryngeal cancer and possessed high self-renewal activity and was sufficient for tumor growth, differentiation, migration, invasion, and chemotherapeutic resistance. They could represent a promising therapeutic target for LSCC.