1.The study of anterior cervical pedicle screw channel in the lower cervical spine
Rongming XU ; Liujun ZHAO ; Weihu MA ; Yanzhao ZHU
Chinese Journal of Orthopaedics 2011;31(12):1337-1343
ObjectiveTo investigate application of the anterior cervical pedicle screw in the lower cervical spine.MethodsTwenty disarticulated human vertebrae(C3-C7) were evaluated with computed tomography for pedicle morphometry Parameters included vertebral body height,vertebral body depth,vertebral body width,outer pedicle width,outer pedicle height,pedicle axis length,transverse section angle,sagittal section angle,transverse intersection point distance and sagittal intersection point distance.On the basis of these data,the screw channel was determined and the screws were inserted in the specimen.Five patients underwent surgical reconstruction using anterior pedicle screw fixation.After surgery,physical examination and roentgenograms and CT scans were performed in all patients.ResultsThe transverse section angle increased from C3(45.7°±4.0°) to C5(52.1°±5.9° ),but decreased from C6(47.8°±6.7°) to C7(44.4°± 8.3°).The sagittal section angle gradually increased from C3 (93.4°±7.2°) to C6( 112.1°±6.2°) but decreased a little to C7(102.7°±8.5°).The distances in transverse section was about 1.97-3.98 mm and in sagittal section was 3.4-7.5 mm.Anterior pedicle screws were inserted successfully in all specimens without critical pedicle wall perforations.Patients were permitted to ambulate the next day after surgery with a cervical collar.Postoperative neurological improvement was observed in all cases.Postoperative radiographic evaluation confirmed proper insertion of anterior pedicle screws without pedicle perforaton.The average follow-up time was 10.6 months.No anterior pedicle screw breakage and loosening was observed.ConclusionThe entry point in anterior pedicle screw should located in 5mm to upper endplate and near anterior median line.The transverse section angle should be 45.7°-52.1°and the sagittal section angle should be 93.4°-112.1°.The lengths of the screw should be about 32 mm.
2.Survival predictive factors in completely resected high-risk Ⅱ/Ⅲ stage colorectal cancer after adjuvant chemotherapy
Yanyan LIU ; Yanzhao JIA ; Yan ZHAO ; Zhihua YAO ; Hongqiang GUO ; Shujun YANG
Cancer Research and Clinic 2011;23(8):535-537
Objective To analyze predictive factors on survival in patients with completely resected high-risk Ⅱ/Ⅲ stage colorectal cancer after adjuvant chemotherapy.Methods According to random number table, 76 cases with completely resected high-risk Ⅱ/Ⅲ stage colorectal cancer after adjuvant chemotherapy were selected, who newly diagnosed and hospitalized in 2004. Their disease-free and overall survivals were followed up.Thymidylate synthase gene polymorphism and microsatellite instability were tested in these cases with microdissection combined with polymerase chain reaction and capillary electrophoresis. Correlation of these factors including clinical characteristics, thymidylate synthase gene polymorphism and microsatellite instability to survival was analyzed with SPSS13.0 software. Results Histologic grades and evaluated lymph node number had significantly difference between two groups of distinct prognosis (χ2 = 7.827, P =0.003 and χ2 = 9.265, P =0.018, respectively), which were also independent predictors on survival proved by COX regression analysis (χ2 = 40.472, P =0.000 and χ2 = 39.528, P =0.000, respectively).Kaplan-Meier survival analysis showed that the median disease-free and overall survival of poor-differentiated adenocarcinoma patients were significantly shorter than those of high and intermediate-differentiated ones (27.67 vs 61.13months, χ2 = 45.015, P =0.000 and 43.13 vs 64.21 months, χ2 = 35.514, P =0.000, respectively), as well, the median disease-free and overall survival of patients with the evaluated lymph node number less than 11 were poorer than those of more than 11 ( 45.65 vs 68.47 months, χ2 = 23.134, P =0.011 and 53.10 vs 70.18months, χ2 = 22.896, P =0.013, respectively).Conclusion Poor-differentiated adenocarcinoma and evaluated lymph node number less than 11 may be predictors on poor survival in patients with completely resected highrisk Ⅱ/Ⅲ stage colorectal cancer after adjuvant chemotherapy.
3.A study of the feasibility of posterior thoracic transarticular pedicle screw fixation
Guanyi LIU ; Rongming XU ; Weihu MA ; Hongyong ZHAO ; Shoohua SUN ; Huajie LIN ; Nanjian XU ; Yanzhao ZHU
Chinese Journal of Orthopaedics 2011;31(8):892-896
Objective To identify the feasibility and the anatomical parameters of posterior transarticular pedicle screw fixation in the thoracic spine, provide a reference for clinical applications. Methods Twenty human cadaveric thoracic spine segments were dissected posteriorly and anteriorly, with care taken to expose the laminas and pedicles. The entrance point of transarticular pedicle screws was located in the 7 mm away from the above at the inferior margin of the lamina and the inside at the exterior margin, respectively. Posterior transarticular pedicle screws implantation was performed under direct visualization into T1,2,T5,6 and T9,10 Under direct abservation, the feasibility of posterior transarticular pedicle screw fixation was assessed. Then a CT was done. On the morphologic CT scan, the angle and length of the transarticular pedicle crew trajectory were measured. Results The thoracic transarticular pedicle screw trajectory were caudal tilting in the sagittal plane and lateral tilting in the axial plane with successful placement. Screws were placed across the facet joint, and from the inferior articular process of upper thoracic vertebra into the pedicle of lower thoracic vertebra. There was little difference between different number of thoracic vertebrae of the angle, but without significance. The average angles of the screws were 41.4°+3.2°caudal tilting in the sagittal plane and 2.1°±0.7° lateral tilting in the axial plane. The average trajectory lengths were (40.6±4.9)mm, and the lengths increased gradually from upper thoracic vertebra to middle and lower. There were significant differences statistically among T1,2, T5,6 and T9.10 (F=74.09, P<0.01 ). Conclusion Posterior transarticular pedicle screw fixation is feasible, and there are some directions for implantating the screws. Transarticular pedicle fixation in the thoracic spine affords an alternative to standard pedicle screw placement for thoracic stabilization.
4.Expression of PTEN protein and clinical significance in diffuse large B lymphomas
Shuna YAO ; Yanyan LIU ; Yan ZHAO ; Zhihua YAO ; Yanzhao JIA ; Jie MA ; Qingxin XIA ; Shujun YANG
Journal of Leukemia & Lymphoma 2010;19(4):200-202
Objective To study PTEN protein expression and clinical significance in patients with diffuse large B cell lymphoma. Methods Immunohistochemical staining was used to determine the PTEN protein expression in 40 cases of primary diffuse large B lymphoma tissuse. The results were analyzed by Kaplan-Merie survival analysis, Log-Rank test and Logistic regression analysis. Results PTEN protein was positive in 16 cases and negative in 24 cases. There was no significant difference between two groups in twoyear overall survival rate(62.5 % vs 66.7 %, P >0.05). Survival analysis showed that patient' s survival time gradually were reduced with extended time between PTEN protein-positive group and negative group, lower in PTEN-positive group than the negative group, but there was no significant difference in survival curve (P >0.05) in the two groups. We compared characteristics of patients between PTEN protein positive and negative groups,including molecular type, patient' s age, stage, LDH, physical score and extranodular invasion, there was no significant difference among them. PTEN protein was not correlated with prognosis, while International Prognosis Index(IPI) was still a risk factor (OR >1). Conclusion PTEN protein expression may not predict the outcome in diffuse large B cell lymphoma, but IPI still is a predictor.
5.Prognostic significance of p53 mutation protein in patients with diffuse large B-cell lymphoma
Yanyan LIU ; Shuna YAO ; Zhihua YAO ; Hongqiang GUO ; Yan ZHAO ; Yanzhao JIA ; Shujun YANG
Journal of Leukemia & Lymphoma 2011;20(8):468-470
Objective To explore the prognostic significance of p53 mutation protein in patients with diffuse large B-cell lymphoma for the purpose of individualized therapy. Methods Newly diagnosed 62 cases were randomly chosen from our hospital, p53 mutation protein and CD10, bcl-6, MUM1 were tested by immunohistochemistry. Correlation of p53 mutation protein with patients ' characteristics, genotype and survival were analysed in the study. Results p53 mutation protein was found in 48.4 % (30/62) of patients.Its expression was only related to initial treatment response (x2 =20.365, P =0.040), including complete remission rate of 33.3 % (10/30) in positive group and 59.4 % (19/32) in negative group, and non-germinal center genotype (x2=31.023, P =0.021) with 83.3 % in positive group and 56.2 % in negative group. No other correlation was not verified with clinical features. Multivariate survival analysis showed that p53 mutation protein was an independent predictor for shorter progress-free and overall survival in positive group (x2 =30.784, P =0.005 and x2 =35.276, P =0.006). Conclusion p53 mutation protein should be an independent predictor with poor prognosis and to direct personalized therapy.
6.SP94 peptide as a specific probe for hepatocellular carcinoma imaging
Yanli LI ; Jie XIAO ; Yan HU ; Xiao LI ; Guobing LIU ; Yanzhao ZHAO ; Hui TAN ; Hongcheng SHI ; Dengfeng CHENG
Chinese Journal of Nuclear Medicine and Molecular Imaging 2017;37(1):10-14
Objective To investigate the capability of 99 Tcm?tricine?EDDA/HYNIC?SFSIIHTPILPL ( SP94) as a specific probe for HCC imaging. Methods HYNIC?SP94 peptide was prepared by solid phase synthesis, followed by 99 Tcm labeling with tricine?EDDA as the coligand. After determination of radiochemical purity and stability, cell binding study was carried out by incubating Huh?7 cells with 99 Tcm?tricine?EDDA/HYNIC?SP94 at different specific activities (2.5, 4.0 and 30.0 GBq/μmol). The biodistribution studies and microSPECT/CT imaging were performed in Huh?7 tumor?bearing mice ( study group) and Hela tumor?bear?ing mice ( control group ) . Statistical analysis was by two?sample t test. Results 99 Tcm?tricine?EDDA/HYNIC?SP94 was synthesized with over 95% of labeling yield, which remained stable in saline and FBS up to 12 h. With increasing concentrations of 99 Tcm?tricine?EDDA/HYNIC?SP94, Huh?7 cell binding increased but became gradually saturated. In biodistribution studies, (1.02±0.26) %ID/g of tracer was accumulated in Huh?7 tumors at 0.5 h after injection of 99 Tcm?tricine?EDDA/HYNIC?SP94, higher than that in the HYNIC?SP94 blocking group ((0.34±0.09) %ID/g;t=3.537, P<0.05). Compared to Hela tumors, Huh?7 tumors were clearly visualized by microSPECT/CT, with which better imaging quality could be achieved with higher specific radioactivity. Conclusion 99 Tcm?tricine?EDDA/HYNIC?SP94 could achieve a high labeling effi?ciency and good in vitro stability as a potential diagnostic tracer specifically targeted for HCC.
7.The expression and significance of SDF-1/CXCR4 biological axis in laryngeal squamous cell carcinoma and lymph node metastasize.
Lan ZHANG ; Chen XIONG ; Yanzhao WU ; Huijing SHI ; Shanghua JING ; Junjian SONG ; Zhen ZHAO ; Baoen SHAN
Journal of Clinical Otorhinolaryngology Head and Neck Surgery 2012;26(18):798-801
OBJECTIVE:
To study the correlation between the stromal cell-derived factor (SDF-1) and the receptor fusin (CXCR4) in carcinoma of larynx, and investigate some mechanisms of SDF-1/CXCR4 during the development, invasion and lymph node metastasis of laryngocarcinoma.
METHOD:
Detecting the expression of SDF-1 and CXCR4 by immunohistochemical method (SP) in laryngocarcinoma, paraneoplastic tissues, normal laryngeal mucosa and cervical lymph node. Using Kruskal-Wallis H test, chi2 test, Spearman rank correlation analysis and so on to do statistical analysis.
RESULT:
The positive expression rate of SDF-1 and CXCR4 in laryngocarcinoma was obviously higher than in paraneoplastic tissues and normal laryngeal mucosa tissues (P < 0.01). And the expression of two proteins was correlated with lymph node metastasis (P < 0.01), clinical stage (P < 0.01) and pathological grading of tumor (P < 0.05). The positive expression rate of SDF-1 and CXCR4 protein in metastasis lymph node tissue was higher than that in non metastasis lymph node tissue (P < 0.01). The expression of SDF-1 is correlated positively with the expression of CXCR4 in laryngocarcinoma.
CONCLUSION
SDF-1 and CXCR4 protein are highly expressed in laryngocarcinoma and in metastasis lymph node tissue. And they are correlated with lymph node metastasis, clinical stage and pathological grading of the tumor. According to the results, the two proteins may relate to infiltration and metastasis of laryngeal squamous cell carcinoma and play a role of synergistic action in the development and invasion of carcinoma of larynx.
Adult
;
Aged
;
Carcinoma, Squamous Cell
;
metabolism
;
pathology
;
Chemokine CXCL12
;
metabolism
;
Female
;
Humans
;
Laryngeal Neoplasms
;
metabolism
;
pathology
;
Lymph Nodes
;
metabolism
;
pathology
;
Lymphatic Metastasis
;
Male
;
Middle Aged
;
Receptors, CXCR4
;
metabolism
8.Clinicopathological characteristics and prognostic factors analysis of patients with esopha-geal cancer
Huilai LYU ; Yanzhao XU ; Zhenhua LI ; Chao HUANG ; Mingbo WANG ; Peng SU ; Zhao LIU ; Ziqiang TIAN
Chinese Journal of Digestive Surgery 2022;21(10):1363-1369
Objective:To investigate the clinicopathological characteristics and prognostic factors of patients with esophageal cancer.Methods:The retrospective case-control study was conducted. The clinicopathological data of 447 patients with esophageal cancer who were admitted to the Fourth Hospital of Hebei Medical University from January 1, 2017 to December 31, 2020 were collected. There were 312 males and 135 females, aged 60(range, 37?82)years. Observation indica-tors: (1) clinicopathological characteristics; (2) treatment; (3) follow-up; (4) analysis of prognostic factors for esophageal cancer. Follow-up using telephone interview or outpatient examination was conducted to detect survival of patients up to December 2021. The total survival time was from the surgery date to death or the last follow-up. Patients with duration of follow-up more than 2 years were included for survival and prognostic analysis. Measurement data with normal distribution were represented as Mean± SD, and measurement data with skewed distribution were represented as M(range). Count data were represented as absolute numbers. Kaplan-Meier method was used to draw survival curves and calculate survival rates. Log-Rank test was used for survival analysis. Univariate analysis was conducted using the Log-rank test. Multivariate analysis was conducted using the COX hazard regression model. Results:(1) Clinicopathological characteristics. Of the 447 patients, 69.80%(312/447) were males and 30.20%(135/447) were females, and there were 3, 18, 101, 229, 93, 3 cases aged 30?39 years, 40?49 years, 50?59 years, 60?69 years, 70?79 years, 80?89 years, respectively. About the pathological type, there were 424 cases with squamous carcinoma, 11 cases with small cell carcinoma, 4 cases with adenosquamous carcinoma, 3 cases with sarco-matoid carcinoma, 2 cases with adenocarcinoma, 1 case with neuroendocrine carcinoma, 1 case with undifferentiated carcinoma, and 1 case with adenoid cystic carcinoma. There were 2 cases with tumor located at cervicothoracic segment, 49 cases with tumor located at upper thoracic segment, 273 cases with tumor located at mid-thoracic segment, and 123 cases with tumor located at lower thoracic segment. There were 6, 24, 74, 59, 192, 80, 12 cases in stage pT0, pT1a, pT1b, pT2, pT3, pT4a, pT4b of pathological T staging, respectively. There were 207, 63, 142, 28, 7 cases in stage pN0, pN1, pN2, pN3, pN4 of pathological N staging by Japan Esophagus Society (JES), respectively. There were 207, 128, 76, 36 cases in stage pN0, pN1, pN2, pN3 of pathological N staging by Union for International Cancer Control (UICC), respectively. About TNM staging, there were 25, 53, 127, 174, 68 cases in stage 0, Ⅰ, Ⅱ, Ⅲ, Ⅳa of JES staging, and 16, 9, 53, 35, 108, 96, 45, 85 cases in stage 0, Ⅰa, Ⅰb,Ⅱa, Ⅱb, Ⅲa, Ⅲb, Ⅲc of UICC staging, respectively. (2) Treatment. Of the 447 patients, 63 cases underwent neoadjuvant therapy(12 cases combined with immunotherapy), 384 cases underwent no neoadjuvant therapy. There were 347, 97, 2, 1 cases with surgical approach as right thoracic approach, left thoracotomy approach, cervical abdominal approach, left thoracoabdominal approach, respectively. There were 316, 5, 126 cases with surgical platform as totally endoscopic esophagec-tomy, Hybrid surgery, open surgery, respectively. There were 350 and 97 cases with digestive recons-truction as posterior mediastinal approach and intrathoracic approach, respectively. Surgical margin as R 0, R 1, R 2 resection was detected in 323, 116, 8 cases, respectively. Six of 447 patients died during the hospital stay. (3) Follow-up. All the 447 patients were followed up for 25(range, 2?48)months, including 233 cases with the follow-up more than 2 years. The median survival time of 233 patients was unreached, and the postoperative 2-year survival rate was 76.8%. (4) Analysis of prognostic factors for esophageal cancer. Results of univariate analysis showed that gender, neoadjuvant therapy, surgical margin, pT staging, pN staging by JES, pN staging by UICC, TNM staging by JES, TNM staging by UICC were related factors influencing prognosis of 233 patients with esophageal cancer ( χ2=6.62, 17.81, 32.95, 37.93, 27.06, 35.56, 45.24, 37.84, P<0.05). Results of multivariate analysis showed that gender, surgical margin, TNM staging by JES were independent factors influencing prognosis of 233 patients with esophageal cancer ( hazard ratio=0.48, 1.94, 1.46, 95% confidence intervals as 0.25?0.91, 1.07?3.52, 1.16?1.84, P<0.05). Conclusions:The incidence of esophageal cancer is relatively high in males, with the onset age mainly distribute in 60?69 years and the mainly pathological type as squamous carcinoma. Patients with esophageal cancer have advanced tumor staging, low proportion of neoadjuvant therapy, high R 0 resection rate of surgical treatment. Gender, surgical margin, TNM staging by JES are independent factors influencing prognosis of patients with esophageal cancer.
9.Comparisons of minimally invasive esophagectomy and open esophagectomy in lymph node metastasis/dissection for thoracic esophageal cancer
Zhenhua LI ; Chunyue GAI ; Yuefeng ZHANG ; Shiwang WEN ; Huilai LV ; Yanzhao XU ; Chao HUANG ; Bo ZHAO ; Ziqiang TIAN
Chinese Medical Journal 2022;135(20):2446-2452
Background::The study aimed to clarify the characteristics of lymph node metastasis (LNM) and to compare the oncologic outcomes of minimally invasive esophagectomy (MIE) with open esophagectomy (OE) in terms of lymph node dissection (LND) in thoracic esophageal cancer patients.Methods::The data from esophageal cancer patients who underwent MIE or OE from January 2016 to January 2019 were retrospectively reviewed. The characteristics of LNM in thoracic esophageal cancer were discussed, and the differences in numbers of LND, LND rate, and LNM rate/degree of upper mediastinum between MIE and OE were compared.Results::For overall characteristics of LNM in 249 included patients, the highest rate of LNM was found in upper mediastinum, while LNM rate in middle and lower mediastinum, and abdomen increased with the tumor site moving down. The patients were divided into MIE ( n = 204) and OE groups ( n = 45). In terms of number of LND, there were significant differences in upper mediastinum between MIE and OE groups (8 [5, 11] vs. 5 [3, 8], P < 0.001). The comparative analysis of regional lymph node showed there was no significant difference except the subgroup of upper mediastinal 2L and 4L group (3 [1, 5] vs. 0 [0, 2], P < 0.001 and 0 [0, 2] vs. 0, P = 0.012, respectively). Meanwhile, there was no significant difference in terms of LND rate except 2L (89.7% [183/204] vs. 71.1% [32/45], P = 0.001) and 4L (41.2% [84/204] vs. 22.2% [10/45], P = 0.018) groups. For LNM rate of T3 stage, there was no significant difference between MIE and OE groups, and the comparative analysis of regional lymph node showed that there was no significant difference except 2L group (11.1% [5/45] vs. 38.1% [8/21], P = 0.025). The LNM degree of OE group was significantly higher than that of MIE group (27.2% [47/173] vs. 7.6% [32/419], P < 0.001), and the comparative analysis of regional LNM degree showed that there was no significant difference except 2L (34.7% [17/49] vs. 7.7% [13/169], P < 0.001) and 4L (23.8% [5/21] vs. 3.9% [2/51], P= 0.031) subgroups. Conclusion::MIE may have an advantage in LND of upper mediastinum 2L and 4L groups, while it was similar to OE in other stations of LND.
10.Effects of macrophage migration inhibitory factor on survival,proliferation,and differentiation of human embryonic stem cells
Ting HUANG ; Xiaohan ZHENG ; Yuanji ZHONG ; Yanzhao WEI ; Xufang WEI ; Xudong CAO ; Xiaoli FENG ; Zhenqiang ZHAO
Chinese Journal of Tissue Engineering Research 2025;29(7):1380-1387
BACKGROUND:Macrophage migration inhibitory factor(MIF)is a pleiotropic cytokine,which is secreted in different types of stem cells and can regulate the proliferation,differentiation and migration of various types of stem cells.Our previous research has confirmed that human embryonic stem cells secrete MIF and that its concentration in the culture medium is relatively stable.However,whether MIF is involved in the survival,proliferation and differentiation of human embryonic stem cells remains unclear. OBJECTIVE:To investigate the effects of MIF on survival,proliferation,and differentiation of human embryonic stem cells. METHODS:(1)Human embryonic stem cells H9 were cultured.The growth curve of cells was detected and plotted by CCK-8 assay.Enzyme-linked immunosorbent assay was used to determine the level of MIF in the medium.(2)To determine the effects of exogenous MIF on the survival and proliferation of human embryonic stem cells,different groups were established:the control group,which was cultured in stem cell medium without any modifications;the exogenous MIF group,which was treated with different concentrations(30,100,300 ng/mL)of MIF in the stem cell medium;the MIF inhibitor ISO-1 group,which was treated with different concentrations(2,7,21 μmol/L)of ISO-1 in the stem cell medium;and the MIF+ISO-1 group,which was treated with different concentrations of ISO-1 along with 100 ng/mL of MIF.Cell viability was assessed using the CCK-8 assay.(3)To further elucidate the effect of MIF gene on survival and proliferation of human embryonic stem cell,the MIF knockout H9 cell line was constructed by CRISPR-Cas 9 technology to observe the lineage establishment.(4)To determine the effect of high concentrations of MIF on human embryonic stem cell differentiation,100 ng/mL MIF and 100 ng/mL of CXCR4 neutralizing antibody were separately added to the normal stem cell culture medium.The expression levels of self-renewal factors(KLF4,c-MYC,NANOG,OCT4,and SOX2)and differentiation transcription factors(FOXA2,OTX2)were measured using real-time quantitative polymerase chain reaction,immunofluorescence staining,and western blot analysis. RESULTS AND CONCLUSION:(1)The logarithmic growth phase of H9 cells was between 3-6 days.Under normal growth conditions,human embryonic stem cells secreted MIF at a concentration of approximately 20 ng/mL,independent of cell quantity.(2)Compared to the control group,the addition of different concentrations of MIF had no effect on the proliferation of human embryonic stem cells(P>0.05).ISO-1 significantly inhibited the proliferation of human embryonic stem cells,with a stronger inhibition observed at higher concentrations of ISO-1(P<0.05).The addition of MIF in the presence of ISO-1 reduced the inhibitory effect of ISO-1(P<0.05).(3)Real-time quantitative polymerase chain reaction showed that knocking out 50%of the MIF gene resulted in a significant decrease in the growth vitality of human embryonic stem cells and failure to establish cell lines.(4)Adding 100 ng/mL exogenous MIF to the culture medium resulted in a decrease in the mRNA,protein,and fluorescence expression levels of the self-renewal transcription factor KLF4,while the mRNA,protein,and fluorescence expression levels of the differentiation factor FOXA2 increased.(5)When 100 ng/mL CXCR4 neutralizing antibody was added to the culture medium,the mRNA and protein expression levels of KLF4 increased,while the mRNA and protein expression levels of FOXA2 decreased,contrary to the expression trend observed in the MIF group.In conclusion,the endogenous secretion of MIF by human embryonic stem cells is essential for their survival.The addition of MIF to the culture medium does not promote the proliferation of human embryonic stem cells.However,it can lead to a decrease in the expression of the self-renewal factor KLF4 and an increase in the expression of the transcription factor FOXA2.This provides a clue for further investigation into the effects and mechanisms of MIF on the differentiation of human embryonic stem cells.The MIF-CXCR4 axis plays a regulatory role in this process.