Cancer stem cells and skin cancer

Skin cancers are the fastest growing type of cancer in the United States and represent the most commonly diagnosed malignancy, surpassing lung, breast, colorectal and prostate cancer. The epidermis is a multilayered epithelium that covers the skin providing a waterproof barrier that essentially controls the rate of water loss from the body. Recently, cancer stem cells (CSCs) are defined as cells with the capability of self-renewal, the potential to develop into any cell in the overall tumour population and to proliferate driving the continued expansion of the population of malignant cells. Thereby, the properties of tumour-initiating cells closely parallel to the features that define normal stem cells, i.e. asymmetric division. The molecular signature of skin stem cells and cancer stem cells is discussed. According to the CSC model, clinical success depends largely on the CSC population either in quantitative terms such as the relative or absolute number of CSCs or qualitative aspects related to biological features of CSCs. The new pharmacological perspectives are also discussed.