LUNG CANCER STEM CELLS:AN UPDATE

Lung cancer is regarded as one of the most common cancers in the world with a worldwide occurrence of approximately 1.8 million cases and an estimated mortality of 1.6 million in 2012 alone.1 In the United States, there are approximately 2,25,000 new cases of lung cancer with over 1,60,000 deaths annually. Lung cancer is a very serious problem of the Indian subcontinent, especially in the lower socioeconomic subgroups. In India lung carcinoma is the 5th most common tumor and 2nd most common tumor in the males as per the ICMR [Indian Council Of Medical Research] registry of 2002.It accounts for 6.9% of new cancer cases detected each year.3 The importance of study of stem cells and cancer stem cells lays in CSC acting as prognostic and therapeutic markers. It is a known fact that there are innate stem cells present in the lining of the bronchial epithelium, at the carina and alveolar lining which help in regeneration of lungs post injury , however there are present similar cells which post driver mutations are christened CSC and help in cancer survival, growth and chemo resistance. CSC also known as “cancer stem-like cells” (CSLCs), or “tumor-initiating cells” (TICs) are heterogeneous cell population comprising of a small subpopulation of cancer cells with the property of self-renewal and differentiation. CSCs are thought to be responsible for cancer initiation, progression, metastasis, recurrence, and drug resistance.Important CSC under study in lung are, CD 133, ALDH 1, CD 44,ABCG2 etc