Abstract 2331: CD271 defines a cancer-initiating cell population in hypopharyngeal cancer

Cancer stem cells (CSCs) or Cancer initiating cells (CICs) contribute to the malignant phenotypes of a variety of cancers, but markers to identify human hypopharyngeal cancer (HPC) stem cells remain poorly understood. We found that the CD271+ but not CD271- cell population sorted from xenotransplanted HPCs possesses tumor-initiating capability in immunodeficient mice. Tumors generated from the CD271+ cells contained both CD271+ and CD271- cells, indicating that the population could undergo differentiation. Immunohistological analyses of the tumors revealed that the CD271+ cells localized to a perivascular niche near CD34+ vasculature, to invasive fronts, and to the basal layer. In accordance with these characteristics, a stemness marker, Nanog, and matrix metaloproteinases (MMPs), which are implicated in cancer invasion, were significantly up-regulated in the CD271+ compared to the CD271- cell population. Furthermore, using primary HPC specimens, we demonstrated that high CD271 expression was correlated with a poor prognosis for patients. Furthermore, RNA interference of CD271 in CD271+ cells decreased efficiency of tumor initiation and migration phenotypes, suggesting that CD271 is indeed functional. Taken together, our findings indicate that CD271 is a novel marker for cancer initiating cells and for HPC prognosis. Citation Format: Nobuyuki Tanaka, Takayuki Imai, Mai Mochizuki, Keiichi Tamai, Kazunori Yamaguchi, Kennichi Satoh, Kazuto Matsuura, Ikuro Sato, Shigeru Saijo, Kazuo Sugamura. CD271 defines a cancer-initiating cell population in hypopharyngeal cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2331. doi:10.1158/1538-7445.AM2015-2331