Neo-adjuvant radiation and intratumoral immunotherapy followed by surgery-NARIS trial for extremity soft tissue sarcoma.

Extremity soft tissue sarcoma (ESTS) is a rare malignant nonepithelial disease, calling for combined modality treatments with surgery to further improve local control rates and long-term survival, especially in patients with multiple local recurrences with or without risk of amputation. In this double-arm, open-label, Phase II clinical trial, we will enroll 30 patients with pathologically confirmed ESTS without nodal involvement or distant metastases. Patients are randomly assigned to the combination treatment group or the radiation monotherapy group. Additionally, tumor and biological samples will be obtained directly before and after neoadjuvant therapy, allowing for studies of immune response and primary drug resistance mechanisms.Clinical Trial Registration: ChiCTR2200060659 (http://www.chictr.org.cn) (ClinicalTrials.gov).

[Box: see text].

[Surgical management of sacral neurogenic tumors].

OBJECTIVE: To observe the efficacy and complications of one-stage tumor resection to treat primary sacral neurogenic tumors and to discuss some details in the clinically relevant anatomy. METHODS: A retrospective analysis of 26 patients with neurogenic turors of the sacral spine who were surgically treated from January 2001 to January 2018, including 16 males and 10 females, aged from 21 to 69 years old with an average age of (39.3±10.9) years old. The courses of diseases ranged from 3 to 56 months with an average of (17.9±10.1) months. The diameters of presacral components ranged from 3.3 to 19.6 cm with an average of (8.7±4.1) cm. The proximal margin of presacral lesions was above the L5S1 level in 6 cases, and lower than L5S1 in 20 cases. A posterior incision approach for one-stage complete resection of the tumor was used firstly, and an anterior approach was combined when necessary. Spinal-pelvic reconstruction with the modified Galveston technique was also carried out in relevant cases. Whether to preserve the tumor-involved nerve roots depended on the situation during the operation. The operation time, intraoperative blood loss, pain relief, and complications were recorded. The lumbosacral spine stability and sacral plexus neurological function were evaluated during postoperative follow-up, and local recurrence and distant metastasis were examined as well. RESULTS: Total excision was achieved in all 26 patients, with an operation time of (160.4±35.3) mins and an intraoperative blood loss of (1 092.3±568.8) ml. Tumors have been removed via a posterior-only approach in 21 cases and via combined anterior/posterior approaches in 5 cases. The diameter of presacral masses components ranged from 11.3 to 19.6 cm with an average of (15.1±3.2) cm in patients with combined anterior/posterior approaches, and ranged from 3.3 to 10.9 cm with an average of (7.2±2.4) cm in patients with a posterior-only approach. Five of the six patients whose proximal margin of presacral masses was above the L5S1 level adopted combined anterior/posterior approaches, and 20 patients lower than the L5S1 level adopted the posterior-only approach. All the patients were followed up for 6 to 82 months with an average of(45.4±18.2)months. Postoperative lumbosacral pain and lower extremity radicular pain were significantly relieved, and sensation, muscle strength and bowel and bladder function were also improved to varying degrees. The postoperative early complications included superficial wound infection in 1 case and cerebrospinal fluid leakage in 2 cases. Pathology confirmed 17 cases of schwannoma, 7 cases of neurofibroma and 2 cases of malignant schwannoma. Local recurrence was observed in two cases of benign neurogenic tumors. One patient with a malignant nerve sheath tumor had lung metastasis, who died 20 months after the operation. In 17 cases of upper sacral neurogenic tumors, 4 cases did not undergo spinal-pelvic reconstruction with internal fixation, of which 2 cases suffered from postoperative segmental instability. Tumor-involved nerve roots were resected during surgery in 7 cases. One of these patients who had S2 and S3 nerve roots sacrificed simultaneously had an impaired bladder and bowel function postoperatively, and did not recover completely. In the other 6 cases, the neurological function was not damaged obviously or recovered well. CONCLUSION: The posterior approach can directly expose the lesions, and it is also convenient to deal with nerve roots and blood vessels. The operation time, intraoperative blood loss, degree of symptom relief, complication rate, and recurrence and metastasis rate can be controlled at an appropriate level. It is a safe and effective surgical approach. When the upper edge of the presacral mass is higher than the L5S1 level or the diameter of the presacral mass exceeds 10 cm, an additional anterior approach should be considered. The stress between the spine and pelvis is high, and internal fixation should be used to restore the mechanical continuity of the spine and pelvis during resection of neurogenic tumors of the high sacral spine. Most of the parent nerve roots have lost their function. Resection of a single parent nerve root is unlikely to cause severe neurological dysfunction, while the adjacent nerve roots have compensatory functions and should be preserved as much as possible during surgery.

Sensitive osteosarcoma diagnosis through five-base telomerase product-triggered CRISPR-Cas12a enhanced rolling circle amplification.

Osteosarcoma is the most frequent primary malignant bone tumor, composed of mesenchymal cells producing osteoid and immature bone. The sensitive detection of telomerase plays a pivotal role in the early diagnosis and therapeutic treatment of osteosarcoma. We report here an in vitro strategy for sensitive telomerase activity detection through the integration of rolling circle amplification (RCA) and a clustered regularly spaced short palindrome repeats (CRISPR)-Cas12a system. In the proposed strategy, telomerase substrate (TS) primers are easily controlled to extend five bases (GGGTT) to give short telomerase extension products (TEP) with definite lengths without adding dATP. The resulting short TEPs can then cyclize the padlock through hybridizing with its two terminals and thus initiate the following RCA. To obtain an improved sensitivity, the CRISPR-Cas12a system is attached to collaterally cut surrounding DNA reporter probes after recognizing the target single strand DNA sequence in the RCA products. The highlights of this strategy are as follows: (i) the short TEP triggered strategy is excellent at detecting low telomerase activity and thus contributes to the early diagnosis of malignant tumors; (ii) highly sensitive telomerase activity detection which is easy to operate from RCA initiated CRISPR-Cas12a; (iii) opening up of a new avenue for telomerase activity detection with a CRISPR-Cas12a system. Finally, the proposed strategy exhibited sensitive telomerase activity detection under optimized experimental parameters and has great application potential for the clinical diagnosis of malignant tumors and the development of anti-cancer drugs.

Suppressing CHD1L reduces the proliferation and chemoresistance in osteosarcoma.

Osteosarcoma (OS) is the most common bone malignant tumor. However, the genetic basis of OS pathogenesis is still not understood, and occurrence of chemo-resistance is a major reason for the high morbidity of OS patients. Recently, chromodomain helicase/ATPase DNA binding protein 1-like gene (CHD1L) has been identified as a gene related to malignant tumor progression. Unfortunately, its effects on OS development and drug resistance are still not understood. In the study, we attempted to investigate the effects of CHD1L on tumorigenesis and chemoresistance in OS. We found that CHD1L expression was markedly up-regulated in OS samples, especially in cisplatin (cDDP)-resistant patients. We also showed that OS cells with CHD1L knockdown were more sensitive to cDDP treatment with lower IC50 values. In addition, we found that CHD1L deletion markedly reduced cell proliferation and induced apoptosis in OS cells with cDDP resistance. Moreover, the properties of cancer stem cells were highly suppressed in cDDP-resistant OS cells following CHD1L knockdown. Furthermore, multidrug resistance protein 1 (MDR-1) expression levels were dramatically decreased in OS cells with cDDP resistance when CHD1L was suppressed. Functional analysis indicated that CHD1L knockdown clearly restrained the activation of ERK1/2, protein kinase B (AKT) and NF-κB signaling pathways in cDDP-resistant OS cells. Consistently, animal experiments suggested that CHD1L suppression mitigated cDDP resistance in the generated in vivo xenografts. Collectively, CHD1L could modulate chemoresistance of OS cells to cDDP, and thus may be inspiring findings for overcoming drug resistance in OS.

Development and proposal of a scoring system for giant cell tumour of the bone around the knee.

PURPOSE: The purpose of this study was to provide the surgeons with effective and reliable guidelines for surgical decision-making by establishing a scoring system for giant cell tumour (GCTSS) based on evidence and expert opinion. METHODS: The modified Delphi technique and analytic hierarchy process were used to establish the GCTSS. The GCTSS was defined and classified based on different surgical methods using data from 207 patients collected retrospectively between October 2003 and December 2014. Finally, prospective data of 40 patients between December 2014 and October 2015 were used to analyze concordance between score categorization and experts' consensus on surgical procedure. RESULTS: A novel GCTSS included pathological fracture, cortical bone destruction, tumour size, and articular surface involved. The total scores ranged from 1 to 12 points. The strategy for each patient was decided: a total score of 1-4 suggested intralesional curettage alone for excellent post-operative function; 5-9 points indicated intralesional curettage with internal fixation for less surgery-related complications; and 10-12 points indicated prosthesis replacement for long-term local control. The κ-statistic for the predictive validity of total score was 0.611. The κ coefficient of each group represented moderate or substantial agreement, which was acceptable. The intraclass correlation coefficient for inter- and intra-observer reliability of total score was 0.831 and 0.740, respectively. CONCLUSIONS: The novel GCTSS is a comprehensive scoring system with content validity that can aid surgeons in assessing the aggressiveness or severity of giant cell tumour and might become a prognostic tool for surgical decision-making.

How to Fill the Cavity after Curettage of Giant Cell Tumors around the Knee? A Multicenter Analysis.

BACKGROUND: Intralesional excision with curettage is the standard method of giant cell tumor (GCT) treatment, but the ideal filling material after curettage remains controversial. The purpose of this study was to compare the oncological and functional outcomes which underwent cementation or bone grafting after GCT curettage around the knee. METHODS: We reported 136 cases with GCTs in distal femur or proximal tibia who accepted curettage from five clinical centers during the last 15 years. All patients were divided into two groups according to filling materials. Recurrence-free survival proportions were used to evaluate oncological outcomes while the Musculoskeletal Tumor Society (MSTS) 93 functional score was used to evaluate functional outcomes. Other parameters including surgical complication, general condition, and radiological classification had been analyzed. The valid statisitical data was analyzed using SPSS 13.0 software. RESULTS: After GCT curettage, 86 patients (63.2%) accepted bone grafting while 50 patients (36.8%) accepted cementation. There was no statistical difference in age, gender, tumor location, radiological classification, fixation, follow-up time, and MSTS 93 functional score between cementation group and bone grafting group. The recurrence-free survival proportions showed that the recurrence rate in bone grafting group was higher than it in cementation group (P = 0.034). Surgical complication was lower in cementation group than that in bone grafting group but without statistically significant difference (P = 0.141). CONCLUSIONS: Parameters including patients' age, gender, tumor location, and radiological classification did not affect surgeons' treatments in cavity filling after GCT curettage. Cementation should be recommended because of easy usage, the similar postoperative knee function with bone grafting, and the better local tumor control than bone grafting.

Cytotoxic monoterpenoid indole alkaloids from Alstonia yunnanensis Diels.

The ethanol extract of the aerial parts of Alstonia yunnanensis Diels afforded five new monoterpenoid indole alkaloids, alstiyunnanenines A-E (1-5), along with one known compound, alstoniascholarine I (6). The structures of the isolated compounds were established based on 1D and 2D (1H-1H COSY, HMQC, and HMBC) NMR spectroscopy, in addition to high resolution mass spectrometry. The isolated compounds were tested in vitro for cytotoxic potential using eight tumor cell lines. As a result, alkaloids 4-6 exhibited cytotoxicities against all tested tumor cell lines, especially against osteosarcoma cell lines (SOSP-9607, MG-63, Saos-2, M663) with IC50 values<6µM.

Advances in Bone-targeted Drug Delivery Systems for Neoadjuvant Chemotherapy for Osteosarcoma.

Targeted therapy for osteosarcoma includes organ, cell and molecular biological targeting; of these, organ targeting is the most mature. Bone-targeted drug delivery systems are used to concentrate chemotherapeutic drugs in bone tissues, thus potentially resolving the problem of reaching the desired foci and minimizing the toxicity and adverse effects of neoadjuvant chemotherapy. Some progress has been made in bone-targeted drug delivery systems for treatment of osteosarcoma; however, most are still at an experimental stage and there is a long transitional period to clinical application. Therefore, determining how to combine new, polymolecular and multi-pathway targets is an important research aspect of designing new bone-targeted drug delivery systems in future studies. The purpose of this article was to review the status of research on targeted therapy for osteosarcoma and to summarize the progress made thus far in developing bone-targeted drug delivery systems for neoadjuvant chemotherapy for osteosarcoma with the aim of providing new ideas for highly effective therapeutic protocols with low toxicity for patients with osteosarcoma.

Expression of Matrix Metalloproteinase-9 and CD34 in Giant Cell Tumor of Bone.

OBJECTIVE: Giant cell tumor of bone (GCTB) invades extensively and metastasizes, however, the pathological grade and imaging findings are not accurate predictors of its prognosis. Thus, the aim of this study was to explore the relationships between expression of cluster of differentiation (CD)34 and matrix metalloproteinase-9 (MMP-9) and the biological behavior of GCTB with the hope of identifying predictors of prognosis. METHODS: Sixty-eight patients with GCTBs attending our institution from September 2008 to August 2013 were enrolled in this prospective study and grouped according to tumor location. Relevant patient characteristics were assessed. Additionally, the expression of CD34 and MMP-9 in these patients was assayed by an immunohistochemistry staining procedure and the relationships between CD34/MMP-9 and microvessel density (MVD) analyzed by Spearman correlation analysis. RESULTS: It was found that CD34 factor localizes in the cytoplasm of the endothelial cells of small blood vessels in the tumor stroma and is strongly expressed in GCTBs. In addition, radiological grading showed that there was significantly more CD34 antibody-labeled MVD in invasive than in non-invasive tumors (P < 0.05) and significantly more CD34 antibody-labeled MVD in patients who developed recurrences than in those who did not (P < 0.05). Expression of MMP-9 was localized in the cytoplasm of tumor cells and the rate of MMP-9 positivity in GCTBs was significantly higher in active and invasive tumors than in non-invasive tumors (P < 0.01). Moreover, there were significantly more MVDs in MMP-9-positive than in MMP-9 negative tumors (P < 0.01). CD34 and MMP-9 are positively correlated with MVD values in GCTBs and closely correlated with their grade of malignancy. CONCLUSION: Expression of CD34 and MMP-9 accurately predicts clinical behavior detection and prognosis of GCTBs.

Inhibition of Growth and Metastasis of Tumor in Nude Mice after Intraperitoneal Injection of Bevacizumab.

OBJECTIVE: To explore the inhibitory effect of bevacizumab, a vascular endothelial growth factor antibody, on angiogenesis in human osteosarcoma of nude mice. METHODS: Twenty-one nude mice were inoculated with red fluorescent protein (RFP)-labeled human osteosarcoma cell line 143B-RFP, that is, clones that expressed RFP in the cytoplasm, and randomly assigned to one of three groups: G1 (Control group, injected with saline solution); G2 (intraperitoneal bevacizumab 2 mg/kg twice per week) and G3 (intraperitoneal bevacizumab 5 mg/kg, twice per week). The tumor-bearing mice were examined in a fluorescence light box that was illuminated periodically. The primary tumors were measured by fluorescence imaging weekly and their volumes calculated. RESULTS: The mean tumor volumes were significantly smaller in the G3 (186.4 ± 100.8 mm(3) ) than the control group (587.0 ± 406.8 mm(3) ) (P < 0.05) on Day 31, and again significantly smaller in the G3 (677.3 ± 461.9 mm(3) ) than the control group (3162.6 ± 1529.2 mm(3) ) on Day 38 (P < 0.01). The average tumor volume in the G2 group was 493.5 ± 425.4 mm(3) on Day 31 and 1870.1 ± 1524.8 mm(3) on Day 38. The effect on tumor volume was greater in the G3 than the G2 group. Three mice in the G2 group, four in the G3 group and four in the control group developed lung metastases that were confirmed by pathological examination; these differences were not statistically significant (P < 0.05). CONCLUSIONS: Bevacizumab exhibits strong antiangiogenesis activity in experimental osteosarcoma in a nude mouse model but does not influence the incidence of lung metastasis. Our findings may have considerable potential for the treatment of osteosarcoma.

Involvement of α5 integrin in survivin-mediated osteosarcoma metastasis.

OBJECTIVE: To investigate the role of survivin in osteosarcoma metastasis. METHODS: Small interfering RNA (siRNA) was used to knockdown the expression of survivin and α5 integrin in the human osteosarcoma cell line MG63. Western blotting and immunostaining methods were used to assessed the effect of survivin knockdown on the expression of α5 integrin through flow cytometry and fluorescence microscopy detection. Meanwhile, the invasion and migration of transfected cells in Transwell and wound healing assays were probed, and the growth situation of these cells transplanted into nude mice was monitored. RESULTS: Knockdown of survivin expression could inhibit the invasion and migration of osteosarcoma MG64 cells in vitro and the expression of α5 integrin on osteosarcoma MG64 cell surface, suggesting that survivin can inhibit the invasion and migration of osteosarcoma cells through downregulation of α5 integrin. Anti-α5 integrin antibody could also markedly decrease the capability of invasion and migration of osteosarcoma MG64 cells. Additionally, knockdown of survivin expression could slow the growth of osteosarcoma MG63 cells transplanted into nude mice. CONCLUSIONS: Survivin-directed anti-tumor strategies might be an effective method in the treatment of osteosarcoma.

Giant cell tumor of the pelvis: a systematic review.

This is a systematic review of articles concerning the morbidity, recurrence rate, treatment and treatment complications of pelvic giant cell tumors (GCTs). The key words "giant cell tumor, pelvis" were used to identify articles which included data on patients with pelvic GCTs in English and Chinese databases of published reports from 1949-2012. The articles were filtered by title, abstract and full text. Thirty-eight articles and 165 patients were identified for this review. Data on all identified patients were studies; data in different articles on the same patients was not used repeatedly. The following patient data were collected where possible and subjected to systematic analysis; age, location of GCT, treatment, follow-up, complications, recurrence and whether alive or dead. The mean age of onset was 33.2 years (range, 14-73 years), the peak ages of onset being between 21 and 40 years. A pronounced sex difference was identified, the male : female ratio being 1:1.7. The acetabulum was the commonest area for pelvic GCTs. Forty-eight tumors were primarily located in the iliac, 60 in the acetabular and 31 in the ischiopubic area. Twenty-seven patients experienced complications of treatment. Patients who had been treated by wide resection had the most complications; these included incisional infection and delayed healing of incisions. Local recurrence was common, having occurred in 39/158 patients (24.6%), comprising 24/72 (33.3%) who had undergone intralesional surgery only; 9/20 (45.0%) who had undergone radiotherapy only; 1/51 (2.0%) who had undergone wide resection; and 5/14 patients (35.7%) who had undergone radiation therapy or cryotherapy plus intralesional surgery. Mortality was low (3.2%, 5/158). Pelvic GCT is not common, the acetabular area appears to the most frequent site and the peak age is the third and fourth decades. Although the recurrence rate is high for all pelvic GCTs, the mortality is low. Treatment has a critical influence on recurrence. In spite of the associated complications, the lower local recurrence rate makes wide resection a reasonable option for patients with extensive and/or aggressive GCTs.

[Impact of sacral nerve root resection on the erectile and ejaculatory function of the sacral tumor patient].

OBJECTIVE: To evaluate the erectile and ejaculatory function of sacral tumor patients after sacral nerve root resection and investigate the relationship of erectile and ejaculatory dysfunction (EED) with the level of sacral nerve injury. METHODS: This retrospective study included 47 male patients aged 16 to 63 (32.6 +/- 6.8) years treated by sacral tumor resection between January 2008 and August 2013. According to the levels of the sacral nerve roots spared in surgery, the patients were divided into four groups: bilateral S1-S3 (n=16), unilateral S1-S3 (n=21), unilateral S1-S2 (n=6), and unilateral S1 (n=4). The patients were followed up for 12 to 41 (27.2 +/- 10.9) months by questionnaire investigation, clinic review, and telephone calls about their erectile and ejaculatory function at 3, 6 and 12 months after surgery and in August 2013. RESULTS: In the bilateral S1-S3 group, the incidence rates of EED were 31.25% (5/16), 25% (4/16), and 12.5% (2/16) at 3, 6, and 12 months respectively after surgery, with recovery of erectile and ejaculatory function in August 2013. The incidence rates of EED in the unilateral S1-S3 group were 85.71% (18/21), 71.43% (15/21), 52.38% (11/21), and 42.86% (9/21) at 3, 6 and 12 months and in August 2013, respectively; those in the unilateral S1-S2 group were 100% (6/6), 83.33% (5/6), 83.33% (5/6), and 66.67% (4/6) at the four time points; and those in the unilateral S1 group were all 100% (4/4). No statistically significant differences were found in the incidence rate of EED among the patients of different ages or tumor types (P > 0.05). CONCLUSION: The incidence of postoperative EED in male patients treated by sacral tumor resection is closely related to the mode of operation. Sparing the S3 nerve root at least unilaterally in sacral tumor resection is essential for protecting the erectile and ejaculatory function of the patient.

Research progress on the livin gene and osteosarcomas.

Osteosarcoma is a common malignant tumor of bone, but mechanisms underlying its development are still unclear. At present, it is believed that the inhibition of normal apoptotic mechanisms is one of the reasons for the development of tumors, so specific stimulation of tumor cell apoptosis can be considered as an important therapeutic method. Livin, as a member of the newly discovered inhibitor of apoptosis proteins (IAPs) family, has specifically high expression in tumor tissues and can inhibit tumor cell apoptosis through multiple ways, which can become a new target for malignant tumor treatment (including osteosarcoma) and might of great significance in the clinical diagnosis of tumors and the screening of anti-tumor agents and carcinoma treatment.

Design of cervical pedicle locator and three-dimensional location of cervical pedicle.

STUDY DESIGN: To develop a high-accuracy, easy-manipulated, and low-cost cervical pedicle three-dimensional locator for guiding cervical pedicle screw placement. OBJECTIVES: To improve the safety of cervical pedicle screw insertion, simplify its manipulation, and offer safety guarantees in clinical application. SUMMARY OF BACKGROUND DATA: Because of the complicacy of the anatomic structure of cervical pedicle, clinical application of cervical pedicle screw remained hard to popularize. And recent advances on cervical pedicle location did not simplify the manipulation of procedure significantly. Without aid of locator, distance and angle errors were difficult to control. So far, the only instrument for the location of pedicle "computer-assisted image-guided surgical system" is too expensive for clinical use. Furthermore, it has not yet been documented on location instrument for insertion of cervical pedicle screws. METHODS: The high-accuracy three-dimensional locator, made of stainless steel was designed to aid cervical pedicle nail placement. The cadavers were inserted nails under guidance of the locator that has been input the corresponding parameters collected from CT images. Results were evaluated by CT scans. RESULTS: A total of 90 nails were inserted into cervical pedicles, 90% of which were found right in the pedicles; 10% had pedicle cortex breaches. Parallel offset error of the locator in cross-sectional and lateral CT image that was 0.56 +/- 0.70 and 1.04 +/- 0.99; angular offset error was 1.69 +/- 2.41 and 6.54 +/- 7.08. CONCLUSION: Three-dimensional locator of cervical pedicle and its localization technique achieved good results for individuated screws insertion into cervical pedicles, having such advantages as easy manipulation, high accuracy, and low cost. The system presented safety guarantee to the application and advanced the prevalence of pedicle techniques. Its principium and design were demonstrated feasible.

Effect of type I collagen on the adhesion, proliferation, and osteoblastic gene expression of bone marrow-derived mesenchymal stem cells.

OBJECTIVE: To investigate the effects of porous poly lactide-co-glycolide (PLGA) modified by type I collagen on the adhesion, proliferation, and differentiation of rabbit marrow-derived mesenchymal stem cells (MSCs). METHODS: The third generation MSCs isolated from mature rabbits by density gradient centrifugation were cultured at different initial concentrations on 0.3 cm x 1.2 cm x 2.0 cm 3-D porous PLGA coated by type I collagen in RPMI 1640 containing 10% fetal calf serum, while cultured on PLGA without type I collagen as control. The cells adhesive and proliferative behavior at 7, 14, and 21 days after inoculation was assessed by determining the incorporation rate of [(3)H]-TdR. In order to examine MSCs differentiation, the expression of osteoblasts marker genes, osteocalcin (OCN), alkaline phosphatase (ALP), osteopontin (OPN) mRNA, were evaluated by reverse transcription-polymerase chain reaction (RT-PCR), and further more, the cell morphology at 21 days was also observed by scanning electron microscope (SEM). RESULTS: Type I collagen promoted cell adhesion on PLGA. The valve was significantly higher than controls (6 h, 2144 cpm+/-141 cpm vs. 1797 cpm+/-118 cpm, P=0.017; 8 h, 2311 cpm+/-113 cpm vs. 1891 cpm+/-103 cpm, P=0.01). The cells which cultured on PLGA coated with type I collagen showed significantly higher cell proliferation than controls on the 7 th day (1021 cpm+/-159 cpm vs. 451 cpm+/-67 cpm, P=0.002), the 14th day (1472 cpm+/-82 cpm vs. 583 cpm+/-67 cpm, P<0.001) and 21 th day (1728 cpm+/-78 cpm vs. 632 cpm+/-55 cpm, P<0.001). Osteoblasts markers, OCN, ALP, OPN mRNA, were all detected on PLGA coated by type I collagen on the 21 th day, but OCN, OPN mRNA could not be found in controls. Spindle and polygonal cells well distributed on the polymer coated by type I collagen while cylindric or round cells in controls. CONCLUSIONS: Type I collagen is effective in promoting the adhesion, proliferation and differentiation of MSCs on PLGA.