| Lung cancer is one of the most commonly happened malignant cancer and also a serious threat to human health. According to the statistics of the WHO, the deaths caused by lung cancer will up to 1 million every year worldwide, and account for 19% of all kinds of cancer deaths. And with the deterioration of the environment and the process of the aging of the population, by 2025 China will be the biggest lung cancer country. The conventional therapy of lung cancer is surgical resection at present. And besides this, give an appropriate radiation therapy, chemotherapy, biological treatment, molecular targeted therapy, immune therapy and other comprehensive treatment according to the patient’s own condition. However, the treatment efficiency is not ideal, especially in the Non-small-cell lung cancer patients with advanced stage. There are two main reasons attributed to this phenomenon. On one hand, it may be due to the high malignant degree of lung cancer, and patients prone to get early metastasis and treatment failure; and on the other hand, it may because the existed treatment can not prevent the progression of lung cancer effectively. However, the two reasons may be caused by the existed of cancer stem cell(CSC) in lung cancer tissue. According to the CSC theory, the so called CSC is a small group of cells which are able to differentiate to heterogeneous cells in cancer tissues. The group of cells are able to initiate tumor occurrence, to induce tumor metastasis and to join the drug resistance. To improve the treatment efficiency, researchers identify and separate lung cancer stem cells, and study the role of CSC in the cancer’s occurrence and progression. And this has become the major role of their work. CD133 is a five trans-membrane glycoprotein and much studies have shown that the cells separated by marking the membrane protein CD133 has the stronger ability to form a sphere, to form a colon and to initiate tumors in mice than CD133 negative cells. So CD133 has been considered as a major cancer stem cell marker of non-small-cell lung cancer(NSCLC), and are widely used in the identify and separate non-small-cell lung cancer stem cell. However, the predicted role of CD133 in the prognostic and clinicopathologic features of NSCLC is still uncertain. Researchers found that the relationship between CD133 expression and prognostic was existed by the clinical data analysis which means that the higher CD133 expression patients have a worse prognosis, while the lower ones have a better prognosis. However, this was not supported by a small part of researchers, and the conclusion remains controversial. To further identify the relationship of CD133 expression and prognosis of Non-small-cell lung cancer patients, we made a systematic review and meta-analysis. Methods:The electronic and manual searches were performed through the database of Pubmed, Web of Science, Scopus, Medline(1966-2014), Embase(1984-2014), Cochrane Library(1988-2014), Chinese CNKI(from January 1, 1982 to January 1, 2014), Chinese Science and technology journal database(1988-2014) and Chinese CBM database(1995-2014) for titles and abstracts by using the following keywords:“CD133”, “ac133” or “Prominin-1”, and “lung cancer” to identify the studies eligible for our analysis. According to the inclusion criterion and exclusion criterion, studies were screened by two researchers to select the eligible studies with the right type of research literature, the right research object, right research methods and proper indexes to evaluate. Once there is a dispute, a third researcher needed to be joined to discuss it. Meta-analysis was performed by using Review Manager 5.2 and the outcomes included the overall survival and various clinicopathological features. Results: A total of 23 studies containing 2538 patients were finally included, and our results showed that the expression level of CD133 was significantly correlated with the overall survival(OR = 2.25, 95% CI: 1.24–4.07, P= 0.008) of NSCLC patients but not with the disease free survival(OR = 1.33, 95% CI = 0.77–2.30, P= 0.31). With respect to clinicpathological features, CD133 expression level was positively correlated with lymph node metastasis(OR = 1.99, 95%CI = 1.06–3.74,P= 0.03), but not correlated with the differentiation(OR = 0.94, 95%CI 0.53–1.68, P= 0.84 random-effect) or the histological classification(OR = 1.00, 95%CI = 0.81–1.23, P= 0.99(ac); OR = 0.87, 95%CI = 0.61–1.24,P= 0.45(sc)) of NSCLC patients. Conclusion: The high expression level of CD133 trends to correlate with a worse prognosis and a higher rate of lymph node metastasis in NSCLC patients, revealing CD133 as a potential pathological prognostic marker for NSCLC patients. |
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