Cancer-associated fibroblasts contribute to the immunosuppressive landscape and influence the efficacy of the combination therapy of PD-1 inhibitors and antiangiogenic agents in hepatocellular carcinoma.

BACKGROUND: Chronic inflammation is considered the most critical predisposing factor of hepatocellular carcinoma (HCC), with inflammatory cell heterogeneity, hepatic fibrosis accumulation, and abnormal vascular proliferation as prominent features of the HCC tumor microenvironment (TME). Cancer-associated fibroblasts (CAFs) play a key role in HCC TME remodeling. Therefore, the level of abundance of CAFs may significantly affect the prognosis and outcome in HCC patients. METHODS: Unsupervised clustering was performed based on 39 genes related to CAFs in HCC identified by single-cell RNA sequencing data. Patients of bulk RNA were grouped into CAF low abundance cluster and high abundance clusters. Subsequently, prognosis, immune infiltration landscape, metabolism, and treatment response between the two clusters were investigated and validated by immunohistochemistry. RESULTS: Patients in the CAF high cluster had a higher level of inflammatory cell infiltration, a more significant immunosuppressive microenvironment, and a significantly worse prognosis than those in the low cluster. At the metabolic level, the CAF high cluster had lower levels of aerobic oxidation and higher angiogenic scores. Drug treatment response prediction indicated that the CAF high cluster could have a better response to PD-1 inhibitors and conventional chemotherapeutic agents for HCC such as anti-angiogenic drugs, whereas CAF low cluster may be more sensitive to transarterial chemoembolization treatment. CONCLUSIONS: This study not only revealed the TME characteristics of HCC with the difference in CAF abundance but also further confirmed that the combination therapy of PD-1 inhibitors and anti-angiogenic drugs may be more valuable for patients with high CAF abundance.

Molecular mechanisms for magnesium-deficiency-induced leaf vein lignification, enlargement and cracking in Citrus sinensis revealed by RNA-Seq.

Citrus sinensis (L.) Osbeck seedlings were fertigated with nutrient solution containing 2 [magnesium (Mg)-sufficiency] or 0 mM (Mg-deficiency) Mg(NO3)2 for 16 weeks. Thereafter, RNA-Seq was used to investigate Mg-deficiency-responsive genes in the veins of upper and lower leaves in order to understand the molecular mechanisms for Mg-deficiency-induced vein lignification, enlargement and cracking, which appeared only in the lower leaves. In this study, 3065 upregulated and 1220 downregulated, and 1390 upregulated and 375 downregulated genes were identified in Mg-deficiency veins of lower leaves (MDVLL) vs Mg-sufficiency veins of lower leaves (MSVLL) and Mg-deficiency veins of upper leaves (MDVUL) vs Mg-sufficiency veins of upper leaves (MSVUL), respectively. There were 1473 common differentially expressed genes (DEGs) between MDVLL vs MSVLL and MDVUL vs MSVUL, 1463 of which displayed the same expression trend. Magnesium-deficiency-induced lignification, enlargement and cracking in veins of lower leaves might be related to the following factors: (i) numerous transciption factors and genes involved in lignin biosynthesis pathways, regulation of cell cycle and cell wall metabolism were upregulated; and (ii) reactive oxygen species, phytohormone and cell wall integrity signalings were activated. Conjoint analysis of proteome and transcriptome indicated that there were 287 and 56 common elements between DEGs and differentially abundant proteins (DAPs) identified in MDVLL vs MSVLL and MDVUL vs MSVUL, respectively, and that among these common elements, the abundances of 198 and 55 DAPs matched well with the transcript levels of the corresponding DEGs in MDVLL vs MSVLL and MDVUL vs MSVUL, respectively, indicating the existence of concordances between protein and transcript levels.

Development of a Self-Restricting CRISPR-Cas9 System to Reduce Off-Target Effects.

Development of the CRISPR-Cas9 gene-editing system has given rise to a new era of gene editing with wide applications in biology, medicine, agriculture, and other fields. However, the overexpression of Cas9 nuclease causes off-target effects and may trigger an immune response in vivo. Therefore, we constructed a self-restricting CRISPR-Cas9 system, where the target gene sequence corresponding to the guide RNA (gRNA) is inserted on either end of the Cas9 promoter. When double-strand breaks (DSBs) are induced in the target gene sequence, the Cas9 promoter is cut off and transcription ceases. With this system, expression of Cas9 protein at 60 h after transfection is only 10% that of the wild-type system, with about 70% promoter deletion efficiency. The target site editing efficiency and homologous recombination efficiency of the self-restricting system remain at about 50% and 30%, respectively, while the frequency of off-target indel formation decreased by 76.7%. Further, the number of indel types was also reduced from 13 to 2. Because this system does not include additional gRNA sequences, the possibility of introducing new off-target mutations is decreased. Importantly, this system is composed of a single plasmid, which could potentially be easily introduced in vivo using a viral vector or nanoparticles.

Excess Copper-Induced Alterations of Protein Profiles and Related Physiological Parameters in Citrus Leaves.

This present study examined excess copper (Cu) effects on seedling growth, leaf Cu concentration, gas exchange, and protein profiles identified by a two-dimensional electrophoresis (2-DE) based mass spectrometry (MS) approach after Citrus sinensis and Citrus grandis seedlings were treated for six months with 0.5 (control), 200, 300, or 400 µM CuCl2. Forty-one and 37 differentially abundant protein (DAP) spots were identified in Cu-treated C. grandis and C. sinensis leaves, respectively, including some novel DAPs that were not reported in leaves and/or roots. Most of these DAPs were identified only in C. grandis or C. sinensis leaves. More DAPs increased in abundances than DAPs decreased in abundances were observed in Cu-treated C. grandis leaves, but the opposite was true in Cu-treated C. sinensis leaves. Over 50% of DAPs were associated with photosynthesis, carbohydrate, and energy metabolism. Cu-toxicity-induced reduction in leaf CO2 assimilation might be caused by decreased abundances of proteins related to photosynthetic electron transport chain (PETC) and CO2 assimilation. Cu-effects on PETC were more pronounced in C. sinensis leaves than in C. grandis leaves. DAPs related to antioxidation and detoxification, protein folding and assembly (viz., chaperones and folding catalysts), and signal transduction might be involved in Citrus Cu-toxicity and Cu-tolerance.

Interactive effects of pH and aluminum on the secretion of organic acid anions by roots and related metabolic factors in Citrus sinensis roots and leaves.

Low pH and aluminum (Al)-toxicity often coexist in acidic soils. Citrus sinensis seedlings were treated with nutrient solution at a pH of 2.5, 3.0, 3.5 or 4.0 and an Al concentration of 0 or 1 mM for 18 weeks. Thereafter, malate, citrate, isocitrate, acid-metabolizing enzymes, and nonstructural carbohydrates in roots and leaves, and release of malate and citrate from roots were measured. Al concentration in roots and leaves increased under Al-toxicity, but it declined with elevating nutrient solution pH. Al-toxicity increased the levels of glucose, fructose, sucrose and total soluble sugars in leaves and roots at each given pH except for a similar sucrose level at pH 2.5-3.0, but it reduced or did not alter the levels of starch and total nonstructural carbohydrates (TNC) in leaves and roots with the exception that Al improved TNC level in roots at pH 4.0. Levels of nonstructural carbohydrates in roots and leaves rose with reducing pH with a few exceptions with or without Al-toxicity. A potential model for the possible role of root organic acid (OA) metabolism (anions) in C. sinensis Al-tolerance was proposed. With Al-toxicity, the elevated pH upregulated the OA metabolism, and increased the flow of carbon to OA metabolism, and the accumulation of malate and citrate in roots and subsequent release of them, thus reducing root and leaf Al and hence eliminating Al-toxicity. Without Al-toxicity, low pH stimulated the exudation of malate and citrate, an adaptive response of Citrus to low pH. The interactive effects of pH and pH on OA metabolism were different between roots and leaves.

[Evaluation of renal tissue ischemia-reperfusion injury with ultrasound radiation force and targeted microbubbles].

OBJECTIVE: To study the sensitivity and feasibility of detecting microvascular inflammation in renal ischemia- reperfusion injury using microbubbles (MB) targeted to the intercellular adhesion molecule ICAM-1 and ultrasound radiation force (USRF). METHODS: Mouse models of kidney ischemia-reperfusion were randomized into 5 groups with reperfusion time of 1, 3, 6, 12, and 24 h (IRlh, IR3h, IR6h, IR12h, and IR24h group, respectively). Each group was subdivided into targeted MB group (MBICAM group) and targeted MB +USRF group (MBICAM+USRF group). Kidney enhancement and the video intensity (VI) of the kidneys were compared among the groups. RESULTS: In normal mice in either MBICAM or MBICAM+USRF group, no obvious enhancement of the kidney or significant increase in VI of the kidneys was observed (P=0.923). The kidneys were enhanced in all the mice with renal ischemia-reperfusion injury, and with the passage of time, the enhancement increased progressively. VI in the kidneys of mice with renal ischemia-reperfusion injury in MBICAM+USRF group increased more significantly compared with the MBICAM group. Significant difference in the VI was noted among the groups with different perfusion time but not between IR12h and IR24h groups. CONCLUSION: Microbubbles targeted to ICAM-1 combined with USRF can effectively evaluate renal ischemia-reperfusion injury in mice and can be used for early evaluation of microvascular inflammation and other endothelial responses.

Influence of cell physiological state on gene delivery to T lymphocytes by chimeric adenovirus Ad5F35.

Adoptive transfer of genetically-modified T cells is a promising approach for treatment of both human malignancies and viral infections. Due to its ability to efficiently infect lymphocytes, the chimeric adenovirus Ad5F35 is potentially useful as an immunotherapeutic for the genetic modification of T cells. In previous studies, it was found that the infection efficiency of Ad5F35 was significantly increased without enhanced expression of the viral receptor after T cell stimulation; however, little is known about the underlying mechanism. Nonetheless, cell physiology has long been thought to affect viral infection. Therefore, we aimed to uncover the physiologic changes responsible for the increased infection efficiency of Ad5F35 following T cell stimulation. Given the complexity of intracellular transport we analyzed viral binding, entry, and escape using a Jurkat T cell model and found that both cell membrane fluidity and endosomal escape of Ad5F35 were altered under different physiological states. This, in turn, resulted in differences in the amount of virus entering cells and reaching the cytoplasm. These results provide additional insight into the molecular mechanisms underlying Ad5F35 infection of T cells and consequently, will help further the clinical application of genetically-modified T cells for immunotherapy.

Chimeric adenoviral vector Ad5F35L containing the Ad5 natural long-shaft exhibits efficient gene transfer into human T lymphocytes.

Adoptive therapy using T cells modified with tumour antigen-specific T cell receptor (TCR) genes has become a popular area of research in tumour biotherapy research. However, the efficiency of this treatment is low. To increase the efficiency of this therapy, the antigen specific TCR expression in the T cells needs to be improved. Adenoviral vector-mediated gene expression is an attractive approach to bypass the issue of TCR gene modification. The efficiency of adenovirus vector serotype 5 (Ad5) infection is low due to the absence of coxsackievirus B-adenovirus receptor (CAR) expression in T cells. In the present study, a chimeric adenoviral vector (Ad5F35L) was generated; this construct contained both the natural long-shaft of Ad5 and the Ad35 knob. A transduction study showed that the Ad5F35L vector exhibited a higher transduction efficiency in human primary T lymphocytes than the Ad5 vector and the Ad5F35S vector, which contained the Ad35 natural short-shaft and the Ad35 knob. Similar transduction efficiencies were observed for both CD4(+) T lymphocytes and CD8(+) T lymphocytes and the transfection was independent of the expression of cell surface receptors. The activation of T lymphocytes resulted in an improvement of the Ad5F35L transduction efficiency in CD4(+) T cells and a decrease in Ad5F35L transduction efficiency in CD8(+) T cells. The results demonstrate that Ad5F35L is a promising viral vector and will facilitate the clinical application of tumour antigen-specific TCR gene therapy.

Identification of a novel HLA-A2-restricted mutated Survivin epitope and induction of specific anti-HCC CTLs that could effectively cross-recognize wild-type Survivin antigen.

Peptide vaccine based on tumor-associated antigen (TAA), which usually belongs to self-antigen with poor immunogenicity, has been considered as an attractive option for treatment of malignant tumors. The ideal TAA epitopes should have stable affinity to major histocompatibility complex (MHC) molecules and elicit strong anti-tumor immune response. Although point-mutation technology of TAA peptide may increase the binding capability to MHC molecules, some previous studies have revealed that part of the variant peptides results in lymphocyte not to effectively cross-recognize and kill the target tumor expressed wild-type TAA. Here, we designed a novel HLA-A2-restricted mutated TAA Survivin epitope nonapeptide Sur79L2 (KLSSGCAFL) that showed higher binding ability compared to wild-type peptide Sur79 (KHSSGCAFL) in T2-binding assays. To investigate whether Sur79L2 can induce Survivin-specific anti-hepatocellular carcinoma (HCC) response, we stimulated tumor-associated lymphocytes from a HCC patient with Sur79L2 in vitro. IFN-γ release and cytotoxicity assays showed Sur79L2 could effectively cross-recognize and lysis T2 cell plus peptide Sur79 and HCC cell lines (expression of wild-type Survivin antigen) in an HLA-A2-restricted manner. In contrast, peptide Sur95 (ELTLGEFLKL) that has been reported as a very promising anti-tumor epitope in a variety of tumors except HCC were not able to generate detectable cytotoxic immune responses against HCC in this study. Our results suggest that point-mutated peptide Sur79L2 is a new HLA-A2-restricted CTL epitope and may be useful for the immunotherapy for patients with HCC.

Akt promotes irradiation-induced regulatory T-cell survival in hepatocellular carcinoma.

BACKGROUND: Radiotherapy is an efficient remedy in the treatment of hepatocellular carcinoma (Hca); however, some cancer cells can still survive from the radiation and the therapeutic effect is to be improved. Regulatory T cell (Tregs)-induced tumor tolerance and Akt expression play important roles in the tumor survival. This study aims to elucidate the role of radiation induces Akt expression in Tregs. METHODS: A rat Hca model was developed. Hca tissue was collected from the rats with or without radiotherapy. The frequency of Treg and apoptotic Treg in Hca tissue was assessed by flow cytometry. A cell culture model was used to investigate the mechanism by which the tumor-infiltrating Tregs survive from irradiation. RESULTS: After radiotherapy, the frequency of Treg was increased in Hca, the frequency of apoptotic Tregs was decreased and the expression of Akt was increased in the remaining Tregs. The results were reproduced in vitro with a cell culture model. The addition of Akt inhibitor blocked the irradiation-induced Treg survival. Tregs with high levels of Akt still preserve the immune suppressor function. CONCLUSIONS: Akt plays an important role in the radiation-induced tumor-infiltrating Treg survival in Hca.

[Left versus right ventricular Tei index for evaluating third-trimester fetal cardiac function in pregnancy-induced hypertension syndrome].

OBJECTIVE: To investigate the value of Tei index and the sensitivity of left versus right ventricular Tei index in evaluating the fetal cardiac function in pregnancy-induced hypertension syndrome in the third trimester. METHODS: Fetal echocardiograms were performed in 30 women with pregnancy-induced hypertension (PIH) syndrome and 55 with normal pregnancy of the third trimester. Tei index was obtained by calculating the ratio of the isovolumic time (isovolumic contraction and relaxation time) to the ejection time of the left and right ventricle. Comparisons of the Tei index were made between the PIH group and control group, and also between the left and right ventricles in each group. RESULTS: Significant difference was found in the left and right ventricular Tei index between PIH group and control group. No difference was noted between the left and right ventricular Tei index in the PIH group. CONCLUSIONS: Tei index is a useful indicator in evaluating fetal global cardiac function, for which purpose the left ventricular Tei index can be as sensitive as the right ventricular Tei index.

[Preliminary study of an intracavitary convex array probe for detecting distal extracranial internal carotid artery by transoral carotid ultrasonography].

OBJECTIVE: To explore the feasibility of using an intracavitary convex array probe for detecting the distal extracranial internal carotid artery (ICA) by transoral carotid ultrasonography (TOCU). METHODS: Forty patients underwent examinations with bilateral ICA inspected with an intracavitary convex array probe by TOCU to observe the internal diameter, visible length, peak systolic velocity (PSV), end-diastolic velocity (EDV) and resistance index (RI). RESULTS: Eight of the 40 patients were excluded from the observation for the presence of carotid plaques. The examination was terminated in two patients due to sensitive throat and severe pharyngeal reflex. The rest of the patients completed the examination of the internal diameter, visible length, PSV, EDV and RI, which showed no statistically significant differences among them (P>0.05). CONCLUSION: Using intracavitary convex array probe, the distal extracranial ICA disease can be diagnosed with higher accuracy.

[Value of ultrasonographic grading with high-frequency probes in distinguishing breast tumors].

OBJECTIVE: To investigate the value of ultrasonographic grading with high-frequency probes in differentiating benign and malignant breast tumors. METHODS: Sixty-four women (mean age 44.5-/+13.7 years) with 79 breast tumors underwent high-frequency ultrasonography to examine the tumor number, size, aspect ratio, shape, boundaries, encapsulation, pseudopod, internal and rear echoes, calcifications, blood perfusion, abnormality lymph nodes in the axilla. The tumors were graded based on these findings using a 10-point grading system. RESULTS: Between the 46 women with benign tumors and 18 with malignant tumors, no significant differences were found in the mean tumor number (1.5-/+1.3 vs 1.1-/+0.3, P>0.05) or size (55.0-/+19.2 mm vs 19.8-/+8.3 mm, P>0.05), but the mean age (41.4-/+12.4 years vs 52.4-/+14.1 years) and ultrasonographic grade (2.8-/+2.2 vs 7.3-/+1.7, P<0.05) differed significantly. The ultrasonographic grade of the breast tumors showed an obvious correlation to the nature of the tumors (r=0.695, P<0.001). CONCLUSION: Grading of breast tumors with high-frequency ultrasonography helps evaluate the nature of the tumors, and a higher score suggests increased probability of malignancy.

[An intracavitary convex array probe for detecting internal carotid artery disease].

OBJECTIVE: To assess the value of an intracavitary convex array probe in detecting internal carotid artery (ICA) disease. METHODS: Eighty-six carotid arteries in 43 cases were examined with intracavitary convex array probe, low-frequency convex array probe and high-frequency linear probe to collect the data including the ICA visible length, peak systolic velocity (PSV), internal diameter, blood vessel shape; common carotid artery (CCA) intimae-medial thickness (IMT), PSV, and internal diameter. RESULTS: Significant differences were noted in the visible length, PSV of ICA, and internal diameter detected by different frequency ultrasound probes. Intracavitary probe and high-frequency probe produced significantly different findings of the blood vessel shape. CONCLUSION: Intracavitary convex array probe has important clinical value in detecting of ICA disease.

[Preliminary study of the value of contrast-enhanced ultrasound with high-frequency linear-array transducer in the diagnosis of carotid stenosis].

OBJECTIVE: To study the value of contrast-enhanced ultrasound with high-frequency linear-array transducer in the diagnosis of carotid stenosis. METHODS: The carotid arteries of 31 patients was examined with color Doppler ultrasound (CDU), harmonic contrast ultrasound (HCU) and digital subtractive angiography (DSA), respectively. The result of DSA was used as the golden standard for evaluating the accuracy, sensitivity and specificity of CDU and HCU in the diagnosis of carotid stenosis. RESULTS: Satisfactory images of 62 carotid arteries were obtained from the patients using HCU with high-frequency linear-array transducer. After intravenous injection of contrast agent, densely dotted hyperechogenic signals were found in the vascular lumen, with stronger intensity than that of the vascular walls. The filling defect areas in the lumen indicated vascular stenosis. Thirty carotid stenoses were detected by DSA, and 25 by CDU. The accuracy, sensitivity and specificity of CDU was 83.3%, 82.0% and 84.9%, respectively. HCU identified 29 carotid stenoses with accuracy, sensitivity and specificity of 96.7%, 96.7% and 97.0%, respectively, significantly higher than those of CDU (P<0.05). CONCLUSION: HCU with high frequency linear-array transducer has better the accuracy than CDU and may serve as a good alternative for diagnosis of carotid stenosis.

Intraperitoneal administration of gonadotropin-releasing hormone-PE40 induces castration in male rats.

AIM: To evaluate the long-term effects of gonadotropinreleasing hormone (GnRH)-based vaccine on levels of GnRH antibody and testosterone, and vaccine-induced immunocastration on sexual behavior of male rats. METHODS: The rats were treated with GnRH-PE40 intraperitoneally every other day for 12 wk. GnRH antibody and testosterone level in rat blood were determined by ELISA and radioimmunoassay, respectively. Morphological changes in testes and sexual behavior of rats were evaluated. RESULTS: GnRH-PE40 induced a high production in GnRH antibody, decreased the serum testosterone level, testis atrophy and sexual function in rats. CONCLUSION: Intraperitoneal administration of GnRHPE40 produces structural and functional castration of male rat reproductive system by inducing anti-GnRH antibody.

[Tumor-specific T cell recptor gene transfection promotes memory T cell differentiation in vitro].

OBJECTIVE: To investigate effect of tumor-specific T cell receptor gene transfection on memory T cell differentiation in vitro. METHODS: TCRVbeta7.1 gene was transferred into peripheral blood mononuclear cells (PBMCs) obtained from healthy adults, and the expression of Vbeta7.1 was detected by flow cytometry before and after the transfection. Memory T cell differentiation was induced by stimulation with the hepatocarcinoma cell line BEL-7402 in vitro. The expression of surface molecules CD45RO, CD45RA and CCR7 was analyzed by flow cytometry to identify the phenotype and subsets of the memory T cells. Fluorescence-activated cell sorting was performed to detect the apoptosis of the tumor cells, and enzyme-linked immunoabsorbent assay was used to determine the production of interferon-gamma (IFN-gamma) for assessing the immune function of the memory T cells. RESULTS: Flow cytometry showed that TCRVbeta7.1 gene was efficiently expressed after transfection. After stimulation by the tumor cells in vitro, the expression of CD45RO in TCRVbeta7.1 gene-modified T cells increased gradually, and analysis of the coexpression of CD45RA and CCR7 revealed that the effector memory T cells constituted the majority of the differentiated memory T cells. The apoptotic rate of the tumor cells induced by the T cells increased significantly with also obviously increased INF-gamma secretion in the memory T cells. CONCLUSION: Tumor-specific TCRVbeta7.1 gene transfection can promote the differentiation of the memory T cells, the majority of which belongs to effector memory T cells that perform immune functions by inducing apoptosis and cytokine secretion.

[Glycodelin in IVF-ET cycles: its association with endometrial receptivity and impact on the outcome of pregnancy].

OBJECTIVE: To investigate the correlation between glycodelin and endometrial receptivity and the value of serum glycodelin detection in in vitro fertilization and embryo transfer (IVF-ET) cycles for evaluation of the outcome of pregnancy. METHODS: Serum glycodelin level in women receiving IVF-ET on the day of oocyte retrieval and embryo transfer was measured by ELISA, and the condition of the endometrium was examined by transvaginal ultrasonography. RESULTS: There was no difference in serum glycodelin level on the day of oocyte retrieval or embryo transfer between the pregnant group and nonpregnant group, but the ratio and difference of serum glycodelin levels on the days of embryo transfer and retrieval were both higher in pregnant group than in the nonpregnant group (2.54-/+2.14 vs 0.96-/+0.51, and 0.91-/+1.22 vs -0.30-/+1.14, respectively). No correlation was found between serum glycodelin levels and endometrial thickness or echo patterns. CONCLUSION: Serum glycodelin levels on the days of retrieval and embryo transfer are not correlated to endometrial thickness or echo patterns, but their dynamic changes reflect endometrial receptivity to a certain extent, which might have prognostic value for pregnancy following IVF-ET.

[Magnetic resonance imaging enhanced by superparamagnetic iron oxide particles in detecting lymph node metastasis of tumors: an experimental study].

OBJECTIVE: To investigate the value of superparamagnetic iron oxide particles (SPIO) in magnetic resonance (MR) imaging for detecting lymph node metastasis of tumors. METHODS: Twelve New Zealand rabbits were used in this study, 6 of which received unilateral intra-muscular inoculation of VX2 carcinoma cells to induce lymph node metastasis of the tumor, and the other 6 served as normal control group. MR images of the lymph nodes of the rabbits were obtained before and 12 h after subcutaneous injection of SPIO, followed by image analysis in correlation with pathological examinations. RESULTS: On plain MR images, normal and metastatic lymph nodes showed similar signal characteristics. After administration of SPIO, the signal intensity of both normal lymph nodes and metastatic ones remained unchanged in spin echo (SE) T1-weighted images. On SE T2-weighted images, the signal intensity of normal lymph nodes significantly decreased heterogeneously, while that of all metastatic lymph nodes remained unchanged. In gradient recalled echo (GRE) T2-weighted images, the signal intensity of normal lymph nodes decreased significantly and homogeneously, while that of 4 rabbits in metastasis group remained unchanged, with the signal intensity in the other 2 rabbits decreased heterogeneously. CONCLUSION: SPIO-enhanced MR imaging can be applied to detect lymph node metastasis of the tumors.