"Head and neck squamous cell carcinoma (HNSCC) ranks sixth worldwide for cancer-related mortality. Research in cancer biology has led to the discovery that many cancers, including HNSCC, appear to be supported by cells that have stem cell like properties. Further, CD44+ population was identified as cancer stem cells in Head and Neck Squamous cell carcinoma. These cancer stem cells have the ability to self-renew, differentiate and develop resistance against chemotherapeutic agents preventing complete elimination of tumor. It was shown these stem cells show abnormal Wnt/B-catenin signaling.

Breast cancer is classified into four subtypes in clinic as ER+ (luminal A or luminal B, usually PR+/− Her2−),overexpressed Her2 (Her2+, usually ER−PR−), negative for ER, PR, and Her2 (ER−PR−Her2−, mostly basal-like) i.e. Triple negative, and normal-like. In breast cancer, showed a small subset of population (CD44+ CD24low/-) that are highly tumorigenic. These cells are termed as Cancer-stem cells (CSC). Owing to heterogeneity nature of these cells, it will be crucial to identify the homogenous population that perhaps could be beneficial in targeted cancer therapy.