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Neuroendocrine prostate cancer (NEPC) is a highly malignant subtype of prostate cancer and it mostly occurs in castration-resistant prostate cancer patients after antiandrogen therapy. The process of cell differentiation to obtain neuroendocrine phenotypes is called neuroendocrine differentiation (NED). It is a proposed mechanism of prostate cancer resistance to androgen-resistance therapy, which is associated with poor prognosis. At present, there is no consensus on the physiological and pathological characteristics of NEPC, and the treatment of this subtype is particularly difficult. This paper reviews the latest findings related to NEPC and NED, and summarizes the most studied targets, hoping to provide new ideas for peer diagnosis, treatment and research of NEPC.
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Objective To investigate the association of lovastatin overcoming gefitinib resistance with the levels of integrin β1 and Survivin in human non-small cell lung cancer (NSCLC) cell line PC9 in vitro, and to explore the possible mechanism. Methods The NSCLC cell line PC9 with acq uired gefitini-resistance were divided into 4 groups; control group (RPM1 1640), gefitinib group (1 /μmol/L gefitinib), lovastatin group (5 μmol/L lovastatin), and gefitinib combined with lovastatin group (1 μmol/L gefitinib+5 /μmol L lovastatin). After treatment with different drugs in each group, the inhibition of cell proliferation was detected by cell counting kit-8 (CCK-8) test, the levels of integrin ft 1 and Survivin mRNA were detected by PCR, and the expressions of integrin (31 and Survivin protein were detected by Western blotting analysis. Results Compared with the control group, lovastatin group and gefitinib group, lovastatin combined with gefitinib treatment had significantly inhibited proliferation of PC9 cells with acquired gefitinib-resistance (P<0. 01), and the expressions of integrin)31. Survivin protein and mRNA in PC9 cells were significantly decreased in the three groups (P<0. 05, P<0. 01). Conclusion Mechanisms of lovastatin combined with gefitinib in overcoming gefitinib resistance may be through blocking integrin β1-p-Akt-Survivin signaling pathway, indicating that the combination treatment might be an effective strategy for gefitinib resistance.
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Objective To observe the influence of interferon-γ(IFN-γ)and tumor necrosis factor-α(TNF-α)treated mesenchymal stem cells (MSCs) on the chemotherapy resistance of colon cancer cells(CRCs) and to discuss the related mechanism. Methods The supernatants of MSCs treated with IFN-γ and TNF-α were collected and used, together with chemotherapy drug cisplatin and 5-fluorouracil, to treat HCT116 and HT29 CRCs. Then the cellular morphology was observed under microscope, and the cell proliferation and apoptosis were examined by MTT and PI/Annexin -FITC assay. Furthermore, the mRNA levels of Bax and Bcl-2 were detected by RT-PCR. Results The CRCs treated with the supernatant of MSCs exposed to inflammatory factors, compared to CRCs treated with the supernatant of MSCs not exposed to inflammatory factors, had a slighter morphology changes, a significantly higher proliferation rate (P<0.05), and a significantly lower apoptosis rate following chemotherapy(P<0.05). Moreover, Bcl-2 mRNA level was higher and Bax mRNA level was lower in CRCs treated with the supernatant of MSCs exposed to inflammatory factors. Conclusion MSCs stimulated with inflammation factors IFN-γ and TNF-α can promote the chemotherapy resistance of human CRCs.
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Objective To establish a cisplatin-resistant 4T1 mouse model of triple negative breast cancer .Meth-ods A drug resistant mice model was established with cisplatin ( DDP ) induction and in-vivo/in-vitro tumorigenic ap-proach.Its resistance characteristics were identified by MTT assay .Changes of drug resistance gene ( MDR1, BCRP, MMP7, GST-π) and protein ( P-gp, BCRP, MMP7) expression, and phosphorate-Akt and total-Akt protein expression were evaluated by real-time PCR, immunohistochemistry and western blot method , respectively.Small animal live imaging technology was applied to detect tumor growth .Results Resistance fold (RF) of cisplatin-resistant 4T1 mouse model was 12.84.The expression of MDR1, BCRP, MMP 7, GST-πmRNA and P-gp, BCRP, MMP 7 proteins in the resistant mice were higher than that in the non-resistant mice .The result of western blot showed that a statistically higher expression of p-Akt in resistant mice than that in non-resistant mice at protein levels (P0.05 ) .Given same dose of DDP , resistant mice showed lower sensitivity than non-resistant mice significantly (P<0.01).Conclusions We have successfully established a cis-platin-resistant triple negative breast cancer model in mice , which provides a new platform for further study on chemoresis-tant reversal strategy and individualized clinical treatment of this disease .
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Objective To observe the effect of the UbcH10 gene silencing on inhibition effect of doxorubicin against in vivo tumor formation of drug-resistant breast cancer MCF-7/ADR cells. Methods An MCF-7/ADR-UbcH10-RNAi cell line with UbcH10 gene silenced was established. Then MCF-7/ADR-UbcH10-RNAi cells and the control cells at logarithmic phase were inoculated into nude mice to establish the subcutaneous tumor model. Doxorubicin or normal saline was administered for a consecutive of two weeks, and then one week later the tumor volumes were determined to analyze the effects of UbcH10 gene silencing on inhibition of tumor formation by doxorubicin. Meanwhile, Western blotting analysis was used to examine the protein expression of UbcH10 and BCL-2; the relationship between UbcH10 and chemosensitivity of tumor cells was analyzed. Results The MCF-7/ADR-UbcH10-RNAi cell line with UbcH10 gene silenced was successfully established with the lentiviral experimental system. The nude mice tumor models were established three weeks after subcutaneous inoculation of tumor cells. The tumor inhibitory rate was 4.16% in the doxorubicin group, which was not significantly different from the control group (P>0.05); while the tumor inhibitory rate was 41.8% in UbcH10-RNAi+doxorubicin group, which was significantly higher than that in the control group (P<0.05). The results of Western blotting analysis showed that the expression levels of UbcH10 in MCF-7/ADR group, MCF-7/ADR+doxorubicin group, and MCF-7/ADR-UbcH10-RNAi+doxorubicin group were 0.81±0.16, 0.78±0.12, and 0.18±0.04, respectively, with the latter being significantly lower than the former two (P<0.05); BCL-2 protein levels in tumors were consistent with those of UbcH10. Conclusion UbcH10 gene silencing can markedly enhance the in vivo sensitivity of drug resistant breast cancer cells to Doxorubicin.
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Colon cancer stem cells (CCSCs) play key roles in tumor initiation, proliferation, metastasis, and chemoresistance. Currently a large number of reports focused on markers of CCSCs, with relative less reporting on CCSCs biological characteristics: proliferation, metastasis, and chemoresistance. This paper reviewed the current research on the biological behavior of CCSCs, with special attention paid on the regulatory effects of microRNAs on CCSCs, hoping to provide reference for improving the diagnosis and treatment of colon cancer.
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Objective: To conduct a integrated analysis of gene expression signature and gene expression profile, so as to provide reference for the prognosis and drug-resistance of serrated colorectal adenocarcinoma (SCA). Methods: We downloaded four gene expression datasets (GSE14333, GSE17538, GSE33113, and GSE37892) of colorectal carcinoma with the follow-up survival data from GEO database, and then integrated them into a entire expression profile (n=600) with batch adjustment and gene expression value extraction. An SCA gene signature and the corresponding expression profile were integrated with the previous expression dataset. Using the gene signature score model we assigned score to each patient in the gene expression dataset and classified the patients into serrated, transitional, or conventional subtypes. Kaplan-Meier analysis and Cox model were used to compare the risks of cancer recurrence between three subtypes of colorectal carcinoma. Gene signature model were also used to generate the score for each patient in the datasets associated with alleviative therapy of colorectal cancer (GSE28702, GSE5851). The SCA drug-resistance was analyzed by observing the therapeutic effective group and non-effective group. Results: According to cut-off value of CRC subtypes, 600 patients in the combined dataset were classified as 50 with serrated subtype, 126 with transitional subtype, and 424 with conventional subtype. Survival analysis showed the serrated and transitional subtypes had very similar scores to predict patient survival, and they were also independent risk factors for postoperative recurrence. When comparing serrated and conventional subtypes, multivariate Cox model analysis indicated the patients with serrated subtype was an unfavorable independent risk factor for prognosis (AHR=1.792, 95%CI 1.011-3.177). Responders to cetuximab treatment had significantly higher signature scores than non-responders (P=0.017), while responders to FOLFOX treatment had similar signature scores with the non-responders. Conclusion: Serrated subtype is an independent risk factor of postoperative recurrence in SCA patients, and is related to the treatment with cetuximab.
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Objective: To investigate the expression of insulin-like growth factor 1 (IGF-1) in epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) resistant non-small cell lung cancer (NSCLC) cell lines and patients, and to discuss the relevant clinical significance. Methods: Levels of IGF-1 were measured by ELISA kit in PC9, A549, H1975 cells and sera of EGFR-TKIs treated NSCLC patients; insulin-like growth factor-binding protein (IGFBP) expression was examined by Western blotting analysis and immunocytochemical method. Cell growth of NSCLC cells treated with gefitinib and BMS536924 (antagonist of IGF-1 receptor) was determined by MTT. The clinicopathological characteristics and survival period of 84 patients receiving EGFR-TKIs treatment were collected and their relationship with IGF-1 expression was analyzed. Results: It was found that IGF-1 level in sensitive cell line PC9 was significantly higher than those in EGFR-TKIs resistant cell lines A549 and H1975 (P<0.05), while IGFBP expression was lower than those in A549 and H1975 cells. Addition of BMS536924 of different concentrations significantly promoted the inhibitory effect of gefitinib against growth of A549 and H1975 cells (P<0.05). The patients with disease progression showed higher IGF-1 expression than those without disease progression (P=0.052), while the patients with intrinsic resistance to EGFR-TKIs had significantly higher IGF-1 level than those with acquired resistance (P=0.02). The patients with IGF-1 negative expression had significantly longer survival than those with positive expression (P=0.002). Conclusion: IGF-1 expression is detected in EGFR-TKIs resistant NSCLC cell lines and patients, and antagonist of IGF-1 receptor can restore the sensitivity to EGFR-TKIs. The expression of IGF-1 is also a prognostic factor of NSCLC patients.
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Objective To investigate the role of E-cadherin in resistance of hepatocellular carcinoma to treatment with epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI). Methods Four liver cancer cell lines were used in the present study, namely, HepG2, BEL-7404, SK-HEP-1 and MHCC97. E-cadherin protein expression in the four cell lines was examined by Western blotting analysis. MTT method was used to examine the relationship between E-cadherin expression and inhibition rates of liver cancer cells treated with EGFR-TKI. Results E-cadherin was positive in HepG2 and BEL-7404 cells, and they were sensitive to EGFR-TKI treatment; the survival rates of HepG2 and BEL-7404 cells were correlated with the concentrations of PD153035 and gefitinib (P0.05). The sensitivity of SK-HEP-1 cells to EGFR-TKI was significantly increased after transfected with E-cadherin compared with those transfected with empty vectors(P<0.05). Conclusion E-cadherin plays an important role in regulating the sensitivity of EGFR molecule targeted therapy.
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Objective: To investigate the mechanism by which wild-type PTEN gene reversing multi-drug resistance (MDR) in human leukemia K562/ADM cells resistant to adriamycin (ADM). Methods: The recombinant adenovirus containing green fluorescent protein and PTEN (Ad-PTEN-GFP) or empty vector (Ad-GFP) was transducted into K562/ADM cells resistant to ADM. The transduction efficiency was assessed by flow cytometry (FCM). Then the cells were treated with different concentrations of ADM, cytarabine (Ara-C) or arsenic trioxide(As203) 3 days after transduction. The proliferation of K562/ADM cells was examined by MTT assay, the apoptosis rate was assessed by FCM, and the IC50 of different drugs was used to calculate the drug resistance reversal fold (RF), so as to observe the effect of PTEN on reversing MDR of the 3 drugs. PTEN, NF-κB, MDR1, MDR-associated protein (MRP) and apoptosis related genes (Bcl-2, Bcl-xL, Bax) were detected by fluorescence quantitative PCR. PTEN, Akt, p-Akt and NF-κB protein levels were detected by Western blotting analysis. Results: The proliferation inhibition rate and apoptosis rate of cells in Ad-PTEN-GFP plus chemotherapeutic groups were significantly higher than those Ad-GFP plus chemotherapeutic groups at 3 days after infection (MOI: 200) (P<0. 05). PTEN transduction promoted the sensitivity of K562/ADM cells to ADM, Ara-C and As203, with the RF being 3. 80, 2. 65 and 2. 64 folds, respectively. K562/ADM cells in Ad-PTEN-GFP group had lower p-Akt and NF-κB (P65) protein levels and lower NF-κB, MDRl, Bcl-2 and Bcl-xL mRNA levels, and up-regulated Bax mRNA level compared with those in Ad-GFP group. Conclusion: Wild-type PTEN gene may reverse drug resistance via inhibiting Akt pathway and regulating its downstream signaling molecules, such as NF-κB, MDR1, Bcl-2 and Bax.
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Objective To investigate the role of compensatory activation of estrogen receptor α (ERα) signaling in acquired resistance to lapatinib of breast cancer cells BT474 and the related mechanism. Methods Real-time PCR and Western blotting analysis were used to determine the changes of HER2 and ERα pathways in BT474 cells treated by lapatinib. Acquired resistant model of rBT474 cellswas induced with increasing concentrations of lapatinib (from 0. 25 μmol/L to 5 μmol/L); the apoptosis in rBT474 cells was determined by flow cytometry. Western blotting analysis was used to evaluate the differences between BT474 and rBT474 in the HER2 and ER pathways. The growth of rBT474 cells treated by lapatinib and/or fulvestrant was detected by MTT assay, andcolony formation was used to observe the possibility of preventing acquired resistance to lapatinib in BT474 cells by double targets therapy. Results The results of real-time PCR and Western blotting analysis showed that Lapatinib inhibited phosphorylation of HER2 and induced expression of forkhead-box protein O 3A (F0X03a) and progesterone receptor (PR) in BT474 cells. Acquired resistance cell model of rBT474 was established in a 5 μmol/L lapatinib condition. Western blotting analysis showed that the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) pathway was inhibited in rBT474 cells compared with that in the BT474 cells, while the mitogen-activated protein kinase (MAPK) pathways, especially the ER pathway, were activated in the BT474 cells. MTT results showed that, Lapatinib combined with fulvestrant had a significantly greater inhibition on rBT474 cell vitality compared with lapatinib alone (P<0. 01). Colony formation results also showed that combination of lapatinib and fulvestrant had a significantly greater inhibition effect against colon formation of BT474 cells compared with each drug alone and DMSO (P<0. 01), showing a possible prevention ability against acquired resistance. Conclusion Compensatory activation of estrogen receptor a signaling might be one of the mechanisms of acquired resistance to lapatinib in HER2-overexpressing/ERcrpositive breast cancer cells, and inhibition of PI3K/AKT and activation of MAPK might be the main reason for compensatory activation of ERα.
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Objective To investigate the anti-tumor effect of doxycycline against ovarian cancer cells and the underlying mechanism. Methods MTT assay was used to test the tumor cell viability after treated with doxycycline alone or in combination with cisplatin. RT-RCR was used to examine CXCR4 mRNA expression in H08910 cells. Western blotting analysis was used to determine CXCR4 protein expression after doxycycline treatment. Results Treatment with low dose of doxycycline (10 ¡j.g/mL) for 48 hours notably inhibited the proliferation of ovarian cancer cell H08910 (P<0. 01), with the inhibition rate being (70±2) % when doxycycline concentration was at 50 jg/mL. Doxycycline combined with cisplatin had greater inhibitory effect against H08910 cells compared with cisplatin alone at the same concentration. Doxycycline treatment down-regulated CXCR4 expression in H08910 cells. Conclusion Doxycycline has a definite inhibitory effect against proliferation of ovarian cancer H08910 cells, and it can increase the sensitivity of tumor cells to cisplatin, which may involve SDF-1/CXCR4 signaling pathway.
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Objective To explore the role of integrin β1 and relevant signaling pathway in acquired resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) gefitinib in non-small cell lung cancer (NSCLC). Methods Human lung adenocarcinoma cell line PC-9 and gefitinib-resistant PC-9/G cell lines were used in the present study. Western blotting analysis was used to examine the expression of integrin β1, Akt and phospho-Akt protein. The inhibitory effects of gefitinib and/or phosphoinositide 3-kinase (PI3K) inhibitor LY294002 and extracellular regulated protein kinases (ERK) inhibitor PD98059 on cellular proliferation were tested by MTT assay. Cell apoptosis was analyzed by Annexin V/PI and TUNEL method. Results Overexpression of integrin β1 was observed in PC-9/G cell line. Silencing integrin β1 by RNAi method inhibited the proliferation and promoted apoptosis of PC-9/G cells. The inhibitory effect of gefitinib against Akt phosphorylation in PC-9/G cells was weaker than that in PC-9 cells. Knockdown of integrin β1 with RNAi decreased the phosphorylation level of Akt. ERK inhibitor PD98059 failed to restore the sensitivity of PC-9/G cells to gefitinib. PI3K inhibitor LY294002 could restore the sensitivity of PC-9/G cells to gefitinib. Conclusion It is suggested that overexpressed integrin β1 can activate the downstream signaling pathways through PI3K, which may be an important mechanism for resistance to EGFR-TKIs.
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Objective: To observe the relationship between drug-resistance and invasive metastatic behaviors in ovarian cancer cells, and to discuss the related mechanism. Methods: Human ovarian cancer cell lines with different levels of cisplatin-resistance, namely, OVCAR-3/DDP-1, -2, and -3, were established in vitro. The cell proliferation, cell cycle, and cell migration and invasion were assessed by MTT assay, flow cytometry, and Transwell migratory and invasive assays. The protein levels of MMP-2, TIMP-2, MMP-9, and TIMP-1 in the culture supernatants were determined by enzyme-linked immunosorbent assay (ELISA). Results: OVCAR-3/DDP-1, -2, -3 cell lines with stable resistance to cisplatin were successfully established, with the resistance indices being 3.87, 8.39, and 13.42, respectively. Compared with the parent cells, OVCAR-3/DDP-1, -2, and -3 exhibited a lower growth rate; the ratios of cells in G0/G 1 phase were increased and those in S phase were decreased, with significant difference found between OVCAR-3/DDP-2 and -3 cells with OVCAR-3 cells(P< 0.05). With the enhancement of drug resistance, the invasion and migration capabilities of OVCAR-3/DDP-1, -2, and -3 cells were increased, with significant difference found between OVCAR-3/DDP-2 and -3 cells with the OVCAR-3 cells(P<0.05). The ratios of MMP-2/TIMP-2 and MMP-9/TIMP-1 were increased in the cisplatin-resistant cells, with significant difference found between the OVCAR-3/DDP-1, -2, and -3 cells with the OVCAR-3 cells (P<0.05). Conclusion: Development and enhancement of cisplatin resistance can promote the invasive and metastatic abilities of OVCAR-3 cells, which is partially related to up-regulated ratios of MMP-2/TIMP-2 and MMP-9/TIMP-1 in the resistant cells.
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K-ras gene mutalion iscommonly seen in lung adenocarcinoma. Cigarette smoking is thought to be an important reason for K-ras gene mutation. Studies have repotted that K-ras mutations can influence the subtyping and prognosis of lung adenocarcinoma. Recently, the techniques to detect K-ras mutation have been continuously improved, greatly promoting the detection sensitivity of K-ras mutations, even in tissues with small amount of tumor component. Emerging data showed that K-ras mutation can induce primary resistance of lung adenocarcinoma to tyrosine kinase inhibitors (TKIs) and decrease the efficacy of chemotherapy. Therefore, K-ras mutation has attracted considerable attention as a target for diagnosis and anticancer therapy. In this review, we summarize recent studies on K-ras mutations in lung adenocarcinoma, and discuss the development, diagnosis, and treatment of lung adenocarcinoma.
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Objective To establish a paclitaxel-resistant BNX mouse model of human lung carcinoma, so as to provide evidences for studying chemoresistant mechanism and for screening of the reversal drugs in vivo. Methods The resistant model was produced by repeating a crossover subcutaneous injection of human lung cancer A549-Taxol cells and transplantation of tumor fragment into immune deficiency mice, so as to increase the tumor forming rate of A549-Taxol cells and shorten the tumor forming time. The expressions of GST-k, P-gpl70 and MMP-7 were examined by immunohistochemical staining. The chemosensitivities of tumor cells to Taxol were tested and IC50 was measured by MTT. Results Tumor niduses were observed subcutaneously in SCID mice 4 months after injection of A549-Taxol cells, and then the tumor fragment or the tumor cells suspension were injected to SCID mice again. After 3 times of crossover injection, the tumor cells grew faster and tumor niduses were formed 2 months after injection. The same procedure was done in BNX mice. Finally, we achieved a successful rate of 80% in tumor implantation in BNX mice; the tumor niduses could be formed in 3 weeks. P-gpl70, GST-* and MMP-7 expression was higher in the experiment group than that in the A549 control group. IC50 value of paclitaxel for A549-Taxol cells was 520 folds that of A549 cells. Conclusion We have successfully established paclitaxel-resistant lung carcinoma model in mice, which provides a new platform for further study on chemoresistant reversal strategy and individualized clinical treatment.
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Objective: To isolate and identify cancer stem cells from esophageal cancer cells (ECCs) using cell surface marker p75NTR. Methods: ECCs were cultured from surgically resected ECC specimens; ECC cell lines TE-1 and Ecal09 were also cultured. The expression of p75NTR in human ECCs was examined by flow cytometry. p75NTR positive cells were isolated from ECCs using magnetic activated cell sorting (MACS) method. The proliferation, differentiation, and the ability of colony-forming in soft agar of the p75 NTR positive cells were observed. The p75NTR positive cells were injected into BALB/c nude mice subcutaneously to observe their tumorigenesis ability. The survival rates of p75NTR positive and negative cells were assessed after treated with chemotherapy drugs to evaluate the resistance of p75NTR positive cells. Results: Six out of the eight cell lines, including SHEC-4, SHEC-6, SHEC-7, SHEC-8, EcalO9, and TE-1, were positive of p75NTR, with the positive rates being 2.71%, 0.32%, 3.35%, 1.13%, 2.15%, and 0.45%. respectively. It was showed that p75 NTR positive cells possessed higher proliferation ability compared with p75NTR negative cells (P<0.01). The p75NTR positive cells had higher colony-forming ability in soft agar compared with p75NTR negative cells (P<0.01). The p75NTR positive cells demonstrated stronger tumorigenesis ability in nude mice. As few as 2 000 SHEC-7 cells could give rise to new tumors in xenotransplantation, with a tumorigenesis ability 50 times as high as that of the p75NTR negative cells. When treated with chemotherapy drugs for 48 h, p75NTR positive cells had significantly higher survival rate than p75NTR negative cells (P<0.05). Conclusion: The p75NTR positive ECCs possess self-renewal, differentiation, and proliferation abilities; they are strongly resistant to chemotherapy drugs, which gives them strong tumorigenesis ability and the characters of tumor stem cells.