Gene Expression Profiling of Lung Atypical Carcinoids and Large Cell Neuroendocrine Carcinomas Identifies Three Transcriptomic Subtypes with Specific Genomic Alterations.

INTRODUCTION: DNA mutational profiling showed that atypical carcinoids (ACs) share alterations with large cell neuroendocrine carcinomas (LCNECs). Transcriptomic studies suggested that LCNECs are composed of two subtypes, one of which shares molecular anomalies with SCLC. The missing piece of information is the transcriptomic relationship between ACs and LCNECs, as a direct comparison is lacking in the literature. METHODS: Transcriptomic and genomic alterations were investigated by next-generation sequencing in a discovery set of 14 ACs and 14 LCNECs and validated on 21 ACs and 18 LCNECs by using custom gene panels and immunohistochemistry for Men1 and Rb1. RESULTS: A 58-gene signature distinguished three transcriptional clusters. Cluster 1 comprised 20 LCNECs and one AC harboring concurrent inactivation of tumor protein p53 gene (TP53) and retinoblastoma 1 gene (RB1) in the absence of menin 1 gene (MEN1) mutations; all cases lacked Rb1 nuclear immunostaining. Cluster 3 included 20 ACs and four LCNECs lacking RB1 alterations and having frequent MEN1 (37.5%) and TP53 mutations (16.7%); menin nuclear immunostaining was lost in 75% of cases. Cluster 2 included 14 ACs and eight LCNECs showing intermediate features: TP53, 40.9%; MEN1, 22.7%; and RB1, 18.2%. Patients in cluster C1 had a shorter cancer-specific survival than did patients in C2 or C3. CONCLUSIONS: ACs and LCNECs comprise three different and clinically relevant molecular diseases, one AC-enriched group in which MEN1 inactivation plays a major role, one LCNEC-enriched group whose hallmark is RB1 inactivation, and one mixed group with intermediate molecular features. These data support a progression of malignancy that may be traced by using combined molecular and immunohistochemical analysis.

Analysis of Fusion Genes by NanoString System: A Role in Lung Cytology?

CONTEXT: - Patients with non-small cell lung cancer harboring ALK receptor tyrosine kinase ( ALK), ROS proto-oncogene 1 ( ROS1), and ret proto-oncogene ( RET) gene rearrangements can benefit from specific kinase inhibitors. Detection of fusion genes is critical for determining the best treatment. Assessing rearrangements in non-small cell lung cancer remains challenging, particularly for lung cytology. OBJECTIVE: - To examine the possible application of the multiplex, transcript-based NanoString system (NanoString Technologies, Seattle, Washington) in the evaluation of fusion genes in lung adenocarcinoma samples. DATA SOURCES: - This study is a narrative literature review. Studies about NanoString, gene fusions, and lung adenocarcinoma were collected from PubMed (National Center for Biotechnology Information, Bethesda, Maryland). We found 7 articles about the application of the NanoString system to detect fusion genes on formalin-fixed, paraffin-embedded tumor tissues and one article evaluating the adequacy of lung cytologic specimens for NanoString gene expression analysis. CONCLUSIONS: - To maximize the yield of molecular tests on small lung biopsies, the NanoString nCounter system has been suggested to detect fusion genes. NanoString fusion gene assays have been successfully applied on formalin-fixed, paraffin-embedded tissues. Although there are only a few studies available, the application of NanoString assays may also be feasible in lung cytology. According to available data, the NanoString system could strengthen the routine molecular characterization of lung adenocarcinoma.

P2X7 protein expression and polymorphism in non-small cell lung cancer (NSCLC).

BACKGROUND: P2X7, a purinergic receptor, plays important roles in inflammatory diseases, but recently its expression has been found in several tumors, suggesting a potential role as a cancer cell biomarker. Moreover, the relative amount of P2X7 varies among human individuals due to numerous single nucleotide polymorphisms resulting in either a loss- or gain-of-function; the P2X7 gene is highly polymorphic, and polymorphisms in the promoter or coding region may modify its expression or function. A polymorphism in exon 13 of the P2X7 receptor gene at the +1513 position (Glu496Ala substitution, corresponding to SNP rs3751143) has been shown to eradicate the function of this receptor and has been correlated with histological variants and clinical parameters in thyroid cancer. Until now, no data regarding P2X7 expression and polymorphisms in lung cancer have been published; based on these premises, we decided to evaluate the impact of the P2X7 expression and polymorphisms in ninety-seven cases of non-small cell lung cancer (NSCLC). RESULTS: No significant difference in the genotype frequency of the A1513C polymorphism was found between the two histological variants of NSCLC, adenocarcinoma and squamous cell carcinoma, and no statistically significant associations were observed between P2X7 protein expression and the main clinico-pathological characteristics of the NSCLC patients. CONCLUSIONS: Based on our results, P2X7 expression and polymorphisms seem to have no potential impact in patients with non-small cell lung cancer; however, further studies will surely provide deeper insights regarding the role of this receptor at the clinical level in NSCLC.

miR-211 modulates gemcitabine activity through downregulation of ribonucleotide reductase and inhibits the invasive behavior of pancreatic cancer cells.

Only a subset of radically-resected pancreatic ductal adenocarcinoma (PDAC) patients benefit from gemcitabine-based chemotherapy, thus the identification of novel prognostic factors is essential. In a high-throughput, microRNA (miRNA) array, miR-211 emerged as the best discriminating miRNA, with high expression associated with long survival. Here, we further explored the biological role of miRNA-211 in gemcitabine activity in the human PDAC cells (SUIT-2) subclones SUIT2-007 and SUIT2-028. Our results showed that miR-211 was expressed differentially in PDAC cells characterized by differential metastatic capability. In particular, S2-028 with lower metastatic ability had a higher expression of miR-211, compared to the S2-007 with higher metastatic capacity. Enforced expression of miR-211 via pre-miR-211 significantly reduced cell migration and invasion (e.g., 40% reduction of invasion of SUIT2 cells, compared to control; p<.05). Moreover, we demonstrated that induction of the miR-211 expression in the cells increased the sensitivity to gemcitabine and reduced the expression of its target ribonucleotide reductase subunit 2 (RRM2). In conclusion, miR-211 functional analyses suggested the role of RRM2 as a target of miR-211 in the modulation of gemcitabine sensitivity. Moreover, inhibition of cell migration and invasion might explain the less aggressive behavior of pancreatic cancer cells with higher expression levels of miR-211.

ALK rearrangement in a large series of consecutive non-small cell lung cancers: comparison between a new immunohistochemical approach and fluorescence in situ hybridization for the screening of patients eligible for crizotinib treatment.

CONTEXT: Echinoderm microtubule associated proteinlike 4-anaplastic lymphoma receptor tyrosine kinase (EML4-ALK) translocation has been described in a subset of patients with non-small cell lung cancer (NSCLC) and has been shown to have oncogenic activity. Fluorescence in situ hybridization (FISH) is used to detect ALK-positive NSCLC, but it is expensive, time-consuming, and difficult for routine application. OBJECTIVE: To evaluate the potential role of immunohistochemistry (IHC) as a screening tool to identify candidate cases for FISH analysis and for ALK inhibitor therapy in NSCLC. DESIGN: We performed FISH and IHC for ALK and mutational analysis for epidermal growth factor receptor (EGFR) and KRAS in 523 NSCLC specimens. We conducted IHC analysis with the monoclonal antibody D5F3 (Ventana Medical Systems, Tucson, Arizona) and a highly sensitive detection system. We also performed a MassARRAY-based analysis (Sequenom, San Diego, California) in a small subset of 11 samples to detect EML4-ALK rearrangement. RESULTS: Of the 523 NSCLC specimens, 20 (3.8%) were positive for ALK rearrangement by FISH analysis. EGFR and KRAS mutations were identified in 70 (13.4%) and 124 (23.7%) of the 523 tumor samples, respectively. ALK rearrangement and EGFR and KRAS mutations were mutually exclusive. Of 523 tumor samples analyzed, 18 (3.4%) were ALK(+) by IHC, 18 samples (3.4%) had concordant IHC and FISH results, and 2 ALK(+) cases (0.3%) by FISH failed to show ALK protein expression. In the 2 discrepant cases, we did not detect any mass peaks for the EML4-ALK variants by MassARRAY. CONCLUSIONS: Our results show that IHC may be a useful technique for selecting NSCLC cases to undergo ALK FISH analysis.

Anaplastic lymphoma kinase gene rearrangements in cytological samples of non-small cell lung cancer: comparison with histological assessment.

BACKGROUND: Anaplastic lymphoma kinase (ALK) gene rearrangements are detected in approximately 5% of cases of non-small cell lung cancer (NSCLC). Patients who are positive for ALK rearrangements may be successfully treated with the ALK inhibitor crizotinib. Because advanced-stage lung cancers are not suitable for surgical resection, approximately 70% of patients are diagnosed via preoperative specimens. In the current study, the authors evaluated the suitability of stained cytologic direct smears and cell blocks for fluorescence in situ hybridization (FISH) to determine ALK status compared with small biopsies. METHODS: A total of 493 consecutive patients with NSCLC were analyzed by FISH for ALK gene rearrangements. The analyzed sample comprised 180 cytological samples, 94 direct smears, 86 cell blocks, and 313 preoperative small biopsies. Moreover, in the same series, 426 patients and 369 patients, respectively, were evaluated for epidermal growth factor receptor and KRAS mutations, respectively. RESULTS: Of the total of 493 patients, 18 patients who were positive for a gene rearrangement (4.4%) demonstrated ALK FISH rearrangements, whereas 387 patients (95.6%) were negative. All other cases were classified as inadequate (7.7%) and insufficient (10.1%). A strong statistical association was found between the cytology and the small biopsy with respect to ALK rearrangements (P=.0048). Fifty-three patients (12.4%) demonstrated an epidermal growth factor receptor mutation, whereas 90 patients (24.4%) were found to have KRAS mutations. None of these patients presented with ALK gene rearrangements. CONCLUSIONS: ALK gene rearrangements may be easily detected in cytological samples and particularly in direct smears, thereby yielding important improvements in the diagnostic approach to patients with advanced NSCLC. Cytological samples may be useful for ALK analysis when insufficient material is available in cell blocks or small biopsies.

FoxP3 expression in papillary thyroid carcinoma: a possible resistance biomarker to iodine 131 treatment.

BACKGROUND: The forkhead transcription factor FoxP3 plays an important role in regulatory T cell (Treg) functions. Tregs are critical in maintaining immunologic tolerance. It has been shown that vaccination against FoxP3-expressing cells is associated with enhancement of tumor immunity. Tregs appear to be increased in blood and in the tumor microenvironment of patients with different cancer types. Tumor cells themselves can express FoxP3. The present study investigates the possible role of FoxP3 expression in a series of human papillary thyroid cancers with a mean follow-up time of 15 years. METHODS: One hundred five cases of papillary thyroid carcinoma (PTC) were investigated, and FoxP3 expression was evaluated in both tumor cells and tumor-associated infiltrates. For all patients, clinical/pathologic features were considered and the results analyzed by statistical tests. RESULTS: Of the 105 PTC cases, 45 (43%) scored FoxP3-positive and 60 (57%) were negative. FoxP3 staining was localized predominantly in the cytoplasm of tumor cells. In some cases, both nuclear and cytoplasmic staining was seen in infiltrating cells. FoxP3 expression in tumor cells was correlated with the presence of extrathyroid invasion (p=0.04) and distant metastasis (p=0.04), but not with overall survival. Interestingly, FoxP3 expression in neoplastic cells was significantly associated with a resistance phenotype to radioiodine treatment (p=0.041). CONCLUSIONS: The data show an association of FoxP3 expression with features of PTC that seem to have a specific impact on radioiodine sensitivity.

Differential expression of extracellular matrix constituents and cell adhesion molecules between malignant pleural mesothelioma and mesothelial hyperplasia.

INTRODUCTION: Malignant pleural mesothelioma (MPM) is a highly aggressive neoplasm associated with asbestos exposure. Currently, the molecular mechanisms that induce MPM development are still unknown. The purpose of this study was to identify new molecular biomarkers for mesothelial carcinogenesis. METHODS: We analyzed a panel of 84 genes involved in extracellular matrix remodeling and cell adhesion by polymerase chain reaction (PCR) array in 15 samples of epithelioid mesothelioma and 10 samples of reactive mesothelial hyperplasia (MH; 3 of 25 samples were inadequate for mRNA analysis). To validate the differentially expressed genes identified by PCR array, we analyzed 27 more samples by immunohistochemistry, in addition to the 25 samples already studied. RESULTS: Twenty-five genes were differentially expressed in MPM and MH by PCR array. Of these we studied matrix metalloproteinase 7 (MMP7), MMP14, CD44, and integrin, alpha3 expression by immunohistochemistry in 26 epithelioid MPM and 26 MH samples from the entire series of 52 cases. We observed higher MMP14 and integrin, alpha3 expression in MPM samples compared with MH samples (p = 0.000002 and p = 0.000002, respectively). Conversely, CD44 expression was low in most (57.7%) mesothelioma samples but only in 11.5% of the MH samples (p = 0.0013). As regards MMP7, we did not observe differential expression between MH and MPM samples. CONCLUSIONS: We have extensively studied genes involved in cell adhesion and extracellular matrix remodeling in MPM and MH samples, gaining new insight into the pathophysiology of mesothelioma. Moreover, our data suggest that these factors could be potential biomarkers for MPM.

Let-7g and miR-21 expression in non-small cell lung cancer: correlation with clinicopathological and molecular features.

MicroRNAs (miRNAs) play a key role in cancer pathogenesis and are involved in several human cancers, including non-small cell lung cancer (NSCLC). This study evaluated Let-7g and miR-21 expression by quantitative real-time PCR in 80 NSCLC patients and correlated the results with their main clinicopathological and molecular features. MiR-21 expression was significantly higher in NSCLC tissues compared to non-cancer lung tissues (p<0.0001), while no significant changes in Let-7g expression were observed between the tumor and normal lung tissues. Target prediction analysis led to the identification of 26 miR-21 and 24 Let-7g putative target genes that play important roles in cancer pathogenesis and progression. No significant association was observed between the analysed miRNAs and the main clinicopathological or molecular characteristics of the NSCLC patients, although both miRNAs were downregulated in squamous cell carcinomas compared to adenocarcinomas. Noteworthy, we observed a significant association between low Let-7g expression and metastatic lymph nodes at diagnosis (p=0.046), as well as between high miR-21 expression and K-Ras mutations (p=0.0003). Survival analysis did not show any significant correlation between prognosis and the analysed miRNAs, although the patients with a high Let-7g and miR-21 expression showed a significantly lower short-term progression-free survival (p=0.01 and p=0.0003, respectively) and overall survival (p=0.023 and p=0.0045, respectively). In conclusion, we showed that Let-7g and miR-21 expression was deregulated in NSCLC and we demonstrated a strong relationship between miR-21 overexpression and K-Ras mutations. Our data indicate that Let-7g and miR-21 profiling combined with the determination of K-Ras mutational status may be considered a useful biomarker for a more effective molecular characterization and clinical management of NSCLC patients.

KIF5B/RET fusion gene analysis in a selected series of cytological specimens of EGFR, KRAS and EML4-ALK wild-type adenocarcinomas of the lung.

A new RET fusion gene has been recently described in a subset of non-small cell lung cancer (NSCLC) identified by specific clinico-pathologic characteristics. This transforming gene arise from the fusion of KIF5B and the RET proto-oncogene, and it is mutually exclusive with EGFR, KRAS and EML4/ALK alterations. For this reason it could represent a putative target for specific inhibitory drugs and its evaluation could be necessary in the future daily molecular characterization of NSCLCs. One of the major challenge in diagnostic molecular pathology is to optimize genotyping tests with the minimally invasive techniques used to acquire diagnostic tumor tissue or cells. This is a significant relevant issue for approximately 60% of NSCLC patients presenting with unresectable disease, where the only pathologic materials available for diagnostic use are small biopsy or cytological specimens. Thus, the aim of this study was to verify the possibility to use RNA purified from cytological specimens to perform KIF5B/RET gene fusion expression analysis. Accordingly, we looked for the presence of the rearrangement in formalin fixed paraffin embedded tissues (FFPETs) and cytological specimens (CSs) of a selected series of "triple-marker" negative adenocarcinomas. The tests conducted revealed the presence of 1 positive patient for variant 1 of KIF5B/RET among the 49 analyzed. The presence of this fusion transcript was found in both FFPET and CS of the same patient demonstrating that the RNA obtained from minimally invasive techniques is perfectly suitable for this kind of tests. The presence of the rearrangement was also confirmed by FISH analysis. In conclusion, our findings confirm that the performance of cytology-based molecular testing for KIF5B/RET rearrangements is at least as effective as histology-based analysis, both with regard to the success rate for nucleic acid isolation and the ability to detect gene alterations.

EML4-ALK translocation in both metachronous second primary lung sarcomatoid carcinoma and lung adenocarcinoma: a case report.

The EML4-ALK gene translocation was described in a non small cell lung cancer (NSCLC) subset, with a potent oncogenic activity. It represents one of the newest molecular targets in NSCLC. We report on the case of a metachronous second primary lung sarcomatoid carcinoma after resection of lung adenocarcinoma both with ALK translocation, in a non-smoking patient. EML4-ALK rearrangement was detected with immunohistochemistry and confirmed with fluorescent in situ hybridization (FISH). To assess the clonal relationship between the two tumors, both adenocarcinoma and sarcomatoid carcinoma were analyzed by array comparative genomic hybridization (aCGH). We observed different genomic profiles suggesting that the tumors arose independently and were thus multiple primaries. To the best of our knowledge, this is the first report concerning the presence of the EML4-ALK fusion gene in a sarcomatoid carcinoma of the lung. Crizotinib, the ALK tyrosine kinase inhibitor, is highly effective in ALK-rearranged NSCLC; therefore, it may be imperative to identify all NSCLC that harbor ALK translocations in the near future. Starting from our evidence, tumors with sarcomatoid histology may need to be screened for the presence of EML4-ALK rearrangement.

Enhancement of the antiproliferative activity of gemcitabine by modulation of c-Met pathway in pancreatic cancer.

Pancreatic-ductal-adenocarcinoma (PDAC) is amongst the most lethal malignancies, mainly because of its metastatic spread and multifactorial chemoresistance. Since c-Met is a marker of pancreatic-cancer-stem-cells (CSC), playing a key role in metastasis and chemoresistance, this study evaluated the therapeutic potential of the novel c-Met/ALK inhibitor crizotinib against PDAC cells, including the Capan-1-gemcitabine-resistant cells (Capan-1-R). Crizotinib inhibited PDAC cell-growth with IC50 of 1.5 µM in Capan-1-R, and synergistically enhanced the antiproliferative and proapoptotic activity of gemcitabine, as detected by sulforhodamine-B-assay, flow cytometry and combination-index method. Capan-1-R had higher expression of the CSC markers CD44+/CD133+/CD326+, but their combined expression was significantly reduced by crizotinib, as detected by quantitative-RT-PCR and FACS-analysis. Similarly, Capan-1-R cells had significantly higher protein-expression of c-Met (≈2-fold), and increased migratory activity, which was reduced by crizotinib (e.g., > 50% reduction of cell-migration in Capan-1-R after 8-hour exposure, compared to untreated-cells), in association with reduced vimentin expression. Capan-1-R had also significantly higher mRNA expression of the gemcitabine catabolism-enzyme CDA, potentially explaining the higher CDA activity and statistically significant lower levels of gemcitabine-nucleotides in Capan-1-R compared to Capan-1, as detected by Liquid-chromatography-massspectrometry. Conversely, crizotinib significantly reduced CDA expression in both Capan-1 and Capan-1-R cells. In aggregate, these data show the ability of crizotinib to specifically target CSC-like-subpopulations, interfere with cell-proliferation, induce apoptosis, reduce migration and synergistically interact with gemcitabine, supporting further studies on this novel therapeutic approach for PDAC.

Phosphatidylinositol-3-kinase α catalytic subunit gene somatic mutations in bronchopulmonary neuroendocrine tumours.

Bronchopulmonary neuroendocrine tumours (BP-NETs) comprise a large spectrum of tumours including typical carcinoids (TCs), atypical carcinoids (ACs), large-cell neuroendocrine carcinomas (LCNECs) and small-cell lung carcinomas (SCLCs) that exhibit considerably different biological aggressiveness and clinical behaviours. The phosphatidylinositol-3-kinase α catalytic subunit (PIK3CA) gene is known to be involved in the pathogenesis of several types of human cancers through gene amplification, deletions or somatic missense mutations within the helical and catalytic domains. However, the PIK3CA gene status in BP-NETs has yet to be explored. This study aimed to investigate the PIK3CA gene status in a large series of BP-NETs by direct gene sequencing and to analyse its correlation with the main clinicopathological parameters. To the best of our knowledge, we demonstrated for the first time a high frequency of somatic missense mutations (23.2%) in the PIK3CA gene in a series of 190 BP-NETs, including 75 TCs, 23 ACs, 17 LCNECs and 75 SCLCs. The frequency of the PIK3CA gene mutation in the kinase domain was higher (17.9%) than that in the helical domain (5.3%). When the mutational status of the PIK3CA gene was compared with the main clinical and pathological characteristics of the BP-NET patients, we found a significant association between PIK3CA gene mutations and BP-NET histology (p=0.011). Interestingly, the frequency of PIK3CA gene mutations increased with the biological aggressiveness of all BP-NETs, except LCNECs. In conclusion, our results suggest that PIK3CA gene mutations may play a key role in tumourigenesis and aggressiveness of BP-NETs. The PIK3CA gene may represent a favourable candidate for an effective therapeutic strategy in the treatment of patients with BP-NETs.

Expression of p-AKT and p-mTOR in a large series of bronchopulmonary neuroendocrine tumors.

Bronchopulmonary neuroendocrine tumors (BP-NETs) are separated into four subgroups: typical carcinoid tumor (TC), atypical carcinoid tumor (AC), large-cell neuroendocrine carcinoma (LCNEC) and small-cell lung carcinoma (SCLC). The signaling pathway involving AKT/mammalian target of rapamycin (mTOR) is crucial to the regulation of cell growth, proliferation and survival, and is frequently activated in human cancers. Consequently, mTOR is considered an attractive target for anticancer agents. The present study aimed to evaluate the expression of phosphorylated AKT and mTOR in a series of BP-NETs, and to analyze the correlations with clinicopathological parameters. p-AKT and p-mTOR levels were determined by immunohistochemistry in a series of 210 BP-NETs, including 85 SCLCs, 17 LCNECs, 26 ACs, 75 TCs and 7 tumorlets. Higher p-AKT and p-mTOR expression levels were identified in the majority of tumorlets and carcinoids in comparison to the LCNECs (P=0.0001) and SCLCs (P=0.0002). Furthermore, a significant association was observed between p-mTOR expression and tumor size (T) in SCLCs (P=0.04) and LCNECs (P=0.03): T3-T4 tumors exhibited significantly lower p-mTOR expression compared to T1-T2 tumors. In conclusion, most of the BP-NETs examined in this study expressed p-AKT and p-mTOR, suggesting that the AKT/mTOR pathway plays an important role in these tumors. Additionally, our results confirm that low- to intermediate-grade tumors are more closely associated to each other than to high-grade tumors, despite sharing common classification and a common origin from neuroendocrine cells. These findings improve our knowledge of the biological characterization of these tumors and indicate new therapeutic opportunities for the treatment of BP-NETs.

Magnetic carbon nanotubes: a new tool for shepherding mesenchymal stem cells by magnetic fields.

AIMS: We investigated the interaction between magnetic carbon nanotubes (CNTs) and mesenchymal stem cells (MSCs), and their ability to guide these intravenously injected cells in living rats by using an external magnetic field. MATERIALS & METHODS: Multiwalled CNTs were used to treat MSCs derived from rat bone marrow. Cytotoxicity induced by nanotubes was studied using the WST-1 proliferation and Hoechest 33258 apoptosis assays. The effects of nanotubes on MSCs were evaluated by monitoring the effects on cellular growth rates, immunophenotyping and differentiation, and on the arrangement of cytoskeletal actin. MSCs loaded with nanotubes were injected in vivo in the portal vein of rats driving their localization in the liver by magnetic field. An histological analysis was performed on the liver, lungs and kidneys of all animals. RESULTS: CNTs did not affect cell viability and their ability to differentiate in osteocytes and adipocytes. Both the CNTs and the magnetic field did not alter the cell growth rate, phenotype and cytoskeletal conformation. CNTs, when exposed to magnetic fields, are able to shepherd MSCs towards the magnetic source in vitro. Moreover, the application of a magnetic field alters the biodistribution of CNT-labelled MSCs after intravenous injection into rats, increasing the accumulation of cells into the target organ (liver). CONCLUSION: Multiwalled CNTs hold the potential for use as nanodevices to improve therapeutic protocols for transplantation and homing of stem cells in vivo. This could pave the way for the development of new strategies for the manipulation/guidance of MSCs in regenerative medicine and cell transplantation.