Additively manufactured bioceramic scaffolds based on triply periodic minimal surfaces for bone regeneration.

The study focused on the effects of a triply periodic minimal surface (TPMS) scaffolds, varying in porosity, on the repair of mandibular defects in New Zealand white rabbits. Four TPMS configurations (40%, 50%, 60%, and 70% porosity) were fabricated with ß-tricalcium phosphate bioceramic via additive manufacturing. Scaffold properties were assessed through scanning electron microscopy and mechanical testing. For proliferation and adhesion assays, mouse bone marrow stem cells (BMSCs) were cultured on these scaffolds. In vivo, the scaffolds were implanted into rabbit mandibular defects for 2 months. Histological staining evaluated osteogenic potential. Moreover, RNA-sequencing analysis and RT-qPCR revealed the significant involvement of angiogenesis-related factors and Hippo signaling pathway in influencing BMSCs behavior. Notably, the 70% porosity TPMS scaffold exhibited optimal compressive strength, superior cell proliferation, adhesion, and significantly enhanced osteogenesis and angiogenesis. These findings underscore the substantial potential of 70% porosity TPMS scaffolds in effectively promoting bone regeneration within mandibular defects.

Automated tooth crown design with optimized shape and biomechanics properties.

Despite the large demand for dental restoration each year, the design of crown restorations is mainly performed via manual software operation, which is tedious and subjective. Moreover, the current design process lacks biomechanics optimization, leading to localized stress concentration and reduced working life. To tackle these challenges, we develop a fully automated algorithm for crown restoration based on deformable model fitting and biomechanical optimization. From a library of dental oral scans, a conditional shape model (CSM) is constructed to represent the inter-teeth shape correlation. By matching the CSM to the patient's oral scan, the optimal crown shape is estimated to coincide with the surrounding teeth. Next, the crown is seamlessly integrated into the finish line of preparation via a surface warping step. Finally, porous internal supporting structures of the crown are generated to avoid excessive localized stresses. This algorithm is validated on clinical oral scan data and achieved less than 2 mm mean surface distance as compared to the manual designs of experienced human operators. The mechanical simulation was conducted to prove that the internal supporting structures lead to uniform stress distribution all over the model.

3D-Printed Filters for Efficient Heavy Metal Removal from Water Using PLA@CS/HAP Composites.

Chitosan/Hydroxyapatite composites, enriched with relatively active -NH2 and -OH groups, have emerged as promising adsorbents for heavy metal removal. In this study, we harnessed the potential of CS/HAP composites by developing monolithic PLA@CS/HAP filters utilizing 3D printing and freeze-drying techniques. These filters possess both macroscopic and microscopic porous structures, endowing them with exceptional capabilities for removing heavy metals from water. The adsorption properties of CS/HAP composites were explored by varying the dosage, duration, and initial concentrations of copper ions. The maximum adsorption capacity for Cu2+ was determined to be approximately 119+/-1 mg/g at the natural pH and 298 K. Notably, the monolithic PLA@CS/HAP filters demonstrated remarkable efficiency in the removal of copper ions, with 90% of copper ions effectively removed within a mere 2-h period in a cyclic adsorption experiment. Furthermore, the PLA@CS/HAP filters exhibited a robust dynamic Cu2+ removal capacity (80.8% or even better in less than 35 min) in a dynamic adsorption experiment. Importantly, all materials employed in this study were environmentally friendly. In summary, the PLA@CS/HAP filter offers advantages such as ease of preparation, eco-friendliness, versatility, and broad applicability in diverse wastewater treatment scenarios, thereby presenting a significant potential for practical implementation.

A Parametric Design Method for Engraving Patterns on Thin Shells.

Designing thin-shell structures that are diverse, lightweight, and physically viable is a challenging task for traditional heuristic methods. To address this challenge, we present a novel parametric design framework for engraving regular, irregular, and customized patterns on thin-shell structures. Our method optimizes pattern parameters such as size and orientation, to ensure structural stiffness while minimizing material consumption. Our method is unique in that it works directly with shapes and patterns represented by functions, and can engrave patterns through simple function operations. By eliminating the need for remeshing in traditional FEM methods, our method is more computationally efficient in optimizing mechanical properties and can significantly increase the diversity of shell structure design. Quantitative evaluation confirms the convergence of the proposed method. We conduct experiments on regular, irregular, and customized patterns and present 3D printed results to demonstrate the effectiveness of our approach.

Efficient Representation and Optimization for TPMS-Based Porous Structures.

In this approach, we present an efficient topology and geometry optimization of triply periodic minimal surfaces (TPMS) based porous shell structures, which can be represented, analyzed, optimized and stored directly using functions. The proposed framework is directly executed on functions instead of remeshing (tetrahedral/hexahedral), and this framework substantially improves the controllability and efficiency. Specifically, a valid TPMS-based porous shell structure is first constructed by function expressions. The porous shell permits continuous and smooth changes of geometry (shell thickness) and topology (porous period). The porous structures also inherit several of the advantageous properties of TPMS, such as smoothness, full connectivity (no closed hollows), and high controllability. Then, the problem of filling an object's interior region with porous shell can be formulated into a constraint optimization problem with two control parameter functions. Finally, an efficient topology and geometry optimization scheme is presented to obtain optimized scale-varying porous shell structures. In contrast to traditional heuristic methods for TPMS, our work directly optimize both the topology and geometry of TPMS-based structures. Various experiments have shown that our proposed porous structures have obvious advantages in terms of efficiency and effectiveness.

Crashworthiness Design of Thin-Walled Tubes Reinforced by Triply Periodic Minimal Surfaces.

This article aims to propose a kind of internally reinforced square tube based on triply periodic minimal surfaces (TPMSs), which can be obtained by computer-assisted techniques and additive manufacturing. To achieve this goal, a finite element simulation model is exploited to simulate the collision situation of reinforced thin-walled tubes. The design of reinforced tubes can be formulated into a multiparameter and multiobjective optimization problem, which can be solved using the well-known non-linear programming by quadratic Lagrangian (NLPQL) optimization method. Three types of TPMS-based tubes and two multicell tubes are compared under the same conditions to show the effectiveness of our method. Through the methods mentioned above, TPMS-reinforced tubes are found to be superior in crashworthiness. This means that the safety performance of the automobiles with lighter weight can be effectively improved. The optimal parameters of three types of TPMS-reinforced tubes under different conditions were obtained, providing the foundations and references for subsequent related studies. In addition, TPMS is first explored in the design of crashworthiness for automobiles in this article. Due to the controllability and implicit functional expression of TPMSs, TPMS-reinforced tubes can be easily controlled and optimized. Meanwhile, it is easy to manufacture them by three-dimensional printing technologies.

MiR-182 promotes cell proliferation by suppressing FBXW7 and FBXW11 in non-small cell lung cancer.

OBJECTIVE: MicroRNAs have been found to be deregulated in lung cancers, which play crucial roles in tumorigenesis and progression. FBXW7 and FBXW11, two important F-box proteins of the ubiquitin-proteasome system (UPS), can target multiple substrates for degradation, in order to regulate cell proliferation and survival in cancers. In the present study, we aimed to explore the potential role and regulating mechanism of miR-182 in non-small cell lung cancer (NSCLC). METHODS: MiRNA expression was evaluated by quantitative reverse-transcription polymerase chain reaction (qRT-PCR). FBXW7, FBXW11, c-Jun, c-Myc and cyclin D protein levels were detected by western blot. Cell growth was determined using cell counting kit (CCK)-8 reagent and colony formation experiment. Then, cell apoptosis and the cell cycle were analyzed on flow cytometry. The target binding activity of miR-182 with FBXW7 or FBXW11 was evaluated through the Dual-Luciferase Reporter Assay System. RESULTS: It was confirmed that miR-182 was significantly upregulated in tumor tissues, compared with adjacent normal tissues, and this was inversely correlated to the protein levels of FBXW7 and FBXW11. The overexpression of miR-182 in NSCLC cells dramatically promoted cell growth, colony formation capacity and cell cycle progression, and inhibited apoptosis in NSCLC cells. In contrast, the downregulation of miR-182 significantly alleviated these properties in vitro. Furthermore, we demonstrated that miR-182 exerted an oncogenic role in NSCLC by directly targeting FBXW7 and FBXW11. CONCLUSION: These results bring new insights into the oncogenic role of miR-182 in NSCLC, indicating that miR-182 might be a novel biomarker for the diagnosis and prognosis of NSCLC.

LncRNA CCAT2 promotes tumorigenesis by over-expressed Pokemon in non-small cell lung cancer.

BACKGROUND: Non-small cell lung cancer (NSCLC) remains one of the most important death-related diseases, with poor effective diagnosis and less therapeutic biomarkers. LncRNA colon cancer-associated transcript 2 (CCAT2) was identified as an oncogenic lncRNA and over-expressed in many tumor cells. The aims of this study were to detect the correlation between CCAT2 and its regulatory genes and then explore the potential mechanism between them in NSCLC. METHODS: In this study, qRT-PCR was used to detect CCAT2, Pokemon and p21 expression. Western-blot was used to detect protein levels of Pokemon and p21. CCK-8 assay and Transwell chambers were used to assess cell viability and invasion. RESULTS: CCAT2 and Pokemon were over-expressed in NSCLC tissue and cells. In NSCLC cells, CCAT2 knockdown significantly decreased cell viability and invasion as well as Pokemon expression, but increased the expression of p21; then CCAT2 overexpression revealed an opposite result. In addition, over-expressed Pokemon reversed the results that induced by si-CCAT2, while down-regulation of Pokemon significantly reversed the results that induced by CCAT2 overexpression. CONCLUSION: The results indicated that CCAT2 promotes tumorigenesis by over-expression of Pokemon, and the potential mechanism might relate to the Pokemon related gene p21.

Generalized Local-to-Global Shape Feature Detection Based on Graph Wavelets.

Informative and discriminative feature descriptors are vital in qualitative and quantitative shape analysis for a large variety of graphics applications. Conventional feature descriptors primarily concentrate on discontinuity of certain differential attributes at different orders that naturally give rise to their discriminative power in depicting point, line, small patch features, etc. This paper seeks novel strategies to define generalized, user-specified features anywhere on shapes. Our new region-based feature descriptors are constructed primarily with the powerful spectral graph wavelets (SGWs) that are both multi-scale and multi-level in nature, incorporating both local (differential) and global (integral) information. To our best knowledge, this is the first attempt to organize SGWs in a hierarchical way and unite them with the bi-harmonic diffusion field towards quantitative region-based shape analysis. Furthermore, we develop a local-to-global shape feature detection framework to facilitate a host of graphics applications, including partial matching without point-wise correspondence, coarse-to-fine recognition, model recognition, etc. Through the extensive experiments and comprehensive comparisons with the state-of-the-art, our framework has exhibited many attractive advantages such as being geometry-aware, robust, discriminative, isometry-invariant, etc.

Anisotropic elliptic PDEs for feature classification.

The extraction and classification of multitype (point, curve, patch) features on manifolds are extremely challenging, due to the lack of rigorous definition for diverse feature forms. This paper seeks a novel solution of multitype features in a mathematically rigorous way and proposes an efficient method for feature classification on manifolds. We tackle this challenge by exploring a quasi-harmonic field (QHF) generated by elliptic PDEs, which is the stable state of heat diffusion governed by anisotropic diffusion tensor. Diffusion tensor locally encodes shape geometry and controls velocity and direction of the diffusion process. The global QHF weaves points into smooth regions separated by ridges and has superior performance in combating noise/holes. Our method's originality is highlighted by the integration of locally defined diffusion tensor and globally defined elliptic PDEs in an anisotropic manner. At the computational front, the heat diffusion PDE becomes a linear system with Dirichlet condition at heat sources (called seeds). Our new algorithms afford automatic seed selection, enhanced by a fast update procedure in a high-dimensional space. By employing diffusion probability, our method can handle both manufactured parts and organic objects. Various experiments demonstrate the flexibility and high performance of our method.

MicroRNA-378 is associated with non-small cell lung cancer brain metastasis by promoting cell migration, invasion and tumor angiogenesis.

Lung cancer is the leading cause of cancer deaths in the world. Brain metastasis (BM) can affect about 25% of non-small cell lung cancer (NSCLC) patients during their lifetime. Efforts to characterize patients that will develop BM have been disappointing. MicroRNAs (miRNAs) play a role in regulating a variety of targets and, consequently, multiple pathways, which make them a powerful tool for early detection of disease, risk assessment and prognosis. In this study, using RT-PCR and further northern blot validation, we confirmed that miR-378 was significantly differentially expressed in the matched NSCLC from 8 patients with BM and 21 without BM. Our study showed evidences that miR-378 is associated with non-small cell lung cancer brain metastasis by promoting cell migration, invasion and tumor angiogenesis. MiR-378 may be a potential biomarker for characterizing non-small cell lung cancer brain metastasis and assisting clinicians in stratifying the high-risk patients on a clinical trial for either prophylactic cranial irradiation or a new intervention that may mitigate BM development, ultimately leading to a new standard of care for NSCLC patients.

The relationship between EGFR gain and VHL loss in lung adenocarcinoma and poor patient survival.

BACKGROUND: The prognosis of lung cancer remains poor and clinically applicable prognostic markers have not yet been satisfactory identified. Several chromosomal copy number alterations (CNAs) have been associated with metastasis, relapse, and survival of patients with lung cancer; however, no study has focused exclusively on identifying CNAs at a gene level. The aim of this study was to identify genes whose CNAs are associated with survival of patients with lung adenocarcinoma. METHODS: The CNA status of a panel of 48 genes was detected by high-resolution array comparative genomic hybridization in 56 lung adenocarcinoma samples. The follow-up time of these patients was 8.5-65.7 months. The gene CNAs were analyzed for their association with patient survival. RESULTS: Cox univariate regression analysis revealed that EGFR gain (hazard ratio (HR) 3.84, 95% confidence interval (CI) 1.62-9.10), VHL loss (HR 4.56, 95% CI 1.85-11.27) and WWOX loss (HR 4.14, 95% CI 1.60-10.69) were each associated with poor survival. Multivariate analyses including EGFR gain, VHL loss and WWOX loss, as well as the clinicopathological variables such as age, sex, tumor size, tumor differentiation and TNM stage showed that EGFR gain (HR 4.63, 95% CI 1.69-12.7) and VHL loss (HR 4.82, 95% CI 1.41-16.43) were independent prognostic factors for poor survival, whereas WWOX loss lost statistical significance. CONCLUSION: These findings suggest that EGFR gain and VHL loss are associated with poor overall survival for lung adenocarcinoma patients and may be used as prognostic markers.

[Effect of cisplatin on the expression of Pokemon gene: experiment with different human lung cancer cells].

OBJECTIVE: To investigate the correlation between Pokemon gene and cisplatin mechanism. METHODS: Human lung adenocarcinoma cells of the lines A549 and AGZY83-a, human lung squamous carcinoma cells of the line HE-99, and human giant cell lung cancer cells of the line 95D were cultured and cisplatin was added into the medium. Other lung cancer cells of the above mentioned lines were cultured in the medium without cisplatin and were used as control groups. RT-PCR and Western blotting were used to detect the mRNA and protein expression of Pokemon. RESULTS: Pokemon mRNA and protein were expressed highly in all the 4 cell lines. The Pokemon gene expression did not changed significantly after cisplatin treatment groups. There were not significant differences in the mRNA and protein expression of Pokemon among the 4 experiment groups and the control groups (all P > 0.05). CONCLUSION: Cisplatin has no effect on the Pokemon gene expression of the human lung cancer cells.

Overexpression of Pokemon in non-small cell lung cancer and foreshowing tumor biological behavior as well as clinical results.

BACKGROUND: Transcription factor Pokemon, a central regulation gene of the important tumor suppressor alternative reading frame (ARF), exerted its activity by acting upstream of many tumor-suppressing genes and proto-oncogenes. Its expression in non-small cell lung cancer (NSCLC) and its clinical significance remains unclear. The aim of this study was to investigate the expression of Pokemon in non-small cell lung cancer and to explore its correlation with the clinical pathological characteristics and its influence on patients' prognosis. AIM: Observe the expression of Pokemon in NSCLC and investigate its mechanism and clinical significance. METHODS: Determine the expression of Pokemon in human NSCLC cell lines as well as 55 cases of NSCLC tumor tissues, tumor adjacent tissues and surrounding tissues by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot, and analyze the relationship between Pokemon expression in NSCLC tumor tissues and clinicopathological features. Determine 62 NSCLC tumor tissues (5 years ago) and p14(ARF) expression with immunohistochemical technique, discuss the correlation between them and assess the effect of Pokemon on prognosis of patients with lung cancer. RESULTS: Pokemon mRNA and protein took on high expression in lung cancer cell lines, and the expression difference between cancer tissues, tumor adjacent tissues and surrounding tissues had statistical significance (P<0.05). Pokemon expression and p14(ARF) expression were negatively correlated (r=-0.287). The expression of Pokemon was determined not to be associated with the patient's sex, age, smoking condition, tumor differentiation degree, histology and lymph node metastasis condition. However, its relationship with TNM staging was established (P<0.05). Furthermore, it was shown that the survival rate of patients with negative Pokemon expression was significantly higher than that of those with positive Pokemon expression (P=0.004), therefore, the expression of Pokemon is believed to be an independent factor affecting prognosis (P=0.034). CONCLUSION: There was high expression of Pokemon in NSCLC, Pokemon exerted carcinogenesis by inhibiting ARF and had some clinical significance for prognostic evaluation of the patients with NSCLC.

Expression of transcription factor Pokemon in non-small cell lung cancer and its clinical significance.

BACKGROUND: Transcription factor Pokemon, a central regulation gene of the important tumor suppressor ARF gene, exerted its activity by acting upstream of many tumor-suppressing genes and proto-oncogenes. Its expression in non-small cell lung cancer (NSCLC) and its clinical significance remains unclear. The aim of this study was to investigate the expression of Pokemon in NSCLC and to explore its correlation with the clinical pathological characteristics and its influence on patients' prognosis. METHODS: Fifty-five cases of NSCLC were involved in this study. The expression of Pokemon in the tumor tissue, the corresponding tumor adjacent tissue and the surrounding tissue was detected via reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting, with the aim of investigating the correlation between the expression of Pokemon in tumor tissue of NSCLC and its clinical pathological characteristics. Moreover, a prognostic analysis was carried out based upon the immunohistochemical (IHC) detection of the expression of Pokemon gene in archival tumor specimens (5 years ago) of 62 cases of NSCLC. RESULTS: Statistical significance of the expression of Pokemon mRNA and protein was determined in the tumor tissue, the tumor adjacent tissue and the surrounding tissue (P<0.05). The expression of Pokemon was determined not to be associated with the patients' sex, age, smoking condition, tumor differentiation degree, histology and lymph node metastasis condition. However, its relationship with TNM staging was established (P<0.05). Furthermore, it was shown that the survival rate of patients with negative Pokemon expression was significantly higher than that of those with positive Pokemon expression (P=0.004), therefore, the expression of Pokemon is believed to be an independent factor affecting prognosis (P=0.034). CONCLUSION: Pokemon was over-expressed in NSCLC tissue and the expression of Pokemon might be of clinical significance in non-small cell lung cancer prognostic evaluation.

[Suppression of RASSF1A gene on human esophageal carcinoma cells: experiments in vitro and in vivo].

OBJECTIVE: To investigate the effect of Ras association domain family 1A (RASSF1A) gene, a new tumor suppressor gene (TSG), on tumorigenesis of human esophageal carcinoma cells. METHODS: pcDNA3.1 (+)-RASSF1A, a plasmid containing RASSF1A gene, and the blank plasmid pcDNA3.1 (+) were transfected into human esophageal carcinoma cells of the line EC9706. The expression of RASSF 1A protein was examined by Western blotting. The changes of cell cycle of stably-transfected cells were determined by flow cytometry (FCM), and the cellular proliferation was analyzed by MTT assay. Fifteen nude mice were randomly divided into 3 groups to be inoculated subcutaneously with EC9706 cells transfected with pcDNA3.1 (+)-RASSF1A, EC9706 cells transfected with pcDNA3.1 (+), and untransfected EC9706 cells respectively. Other 5 nude mice were used as controls. Four weeks later, the mice were killed to take out the carcinoma tissues. FCM was used to analyze the cell cycle. RESULTS: Western blotting showed that RASSF1A protein was expressed highly in the stably transfected cells. The cell viability and growing speed were decreased obviously in the cells expressing of RASSF1A (both P < 0.01); FCM showed that the proportion of cells at the G(1) phase of the EC9706 cells expressing RASSF1A was significantly higher than those in the blank plasmid group and untransfected group (both P < 0.01). The size of the EC9706 cells obtained from the nude mice inoculated with the EC9706 cells transfected with pcDNA3.1 (+)-RASSF1A was significantly smaller than those of the pcDNA3.1 (+) group and blank plasmid group (both P < 0.05). CONCLUSION: Expression of exogenous RASSF1A inhibits the progression of human esophageal carcinoma cells in vitro and in vivo. As a tumor suppressor gene, it plays an important role in origination, progression and metastasis of esophageal carcinoma.

[Hypermethylation of promoter region of RAS association domain family gene1A in esophageal squamous cell carcinoma and significance thereof].

OBJECTIVE: To investigate the hypermethylation of the promoter region of RAS association domain family gene1A (RASSF1A) and its relationship with esophageal squamous cell carcinoma. METHODS: Sixty-six patients with esophageal squamous carcinoma, 60 males and 6 females, aged 59 +/- 8 (44 - 76), underwent resection of the tumor. Methylation-specific PCR (MSP) was used to detect the hypermethylation of promoter region of RASSF1A in the carcinoma tissues and the adjacent normal tissues. RESULTS: The hypermethylation rate of RASSF1A promoter in the tumor tissues was 48. 5% (32/66), significantly higher than that in the adjacent normal tissues (6.1%, 4/66, P < 0.05). The hypermethylation rate of RASSF1A promoter of the patients with lymph node metastasis was 61.1%, significantly higher than that of the patients without lymph node metastasis (33.3%, chi(2) = 5.055, P = 0.025). The hypermethylation rate of RASSF1A promoter in the esophageal squamous cell carcinoma at advanced stages (stages III - IV) was 69.2%, significantly higher than that in the esophageal squamous cell carcinoma at early stages (stages I - II, 35.0%, chi(2) = 7.392, P = 0.007). The hypermethylation rates of RASSF1A promoter in the high, moderate, and low differentiation tumors were 61.5% (16/26), 46.2% (12/26), and 28.6% (4/14) respectively without significant differences among them (chi(2) = 4.053, P = 0.132). CONCLUSION: Abnormal methylation exists in the RASSF1A promoter in esophageal squamous cell carcinoma. The hypermethylation of RASSF1A promoter is related to lymph node metastasis and TNM stage.

[Expression and clinical significance of Pokemon in non-small cell lung cancer].

BACKGROUND: Proto-oncogene Pokemon is the special transcription inhibitor of ARF,which can regulate cell growth and differentiation by ARF-P53 path.It may be the important monitoring target of tumor because of being upstream region of many tumor suppressor genes and proto-oncogenes.The aim of this study is to explore the clinical significance of Pokemon gene in non-small cell lung cancer(NSCLC). METHODS: Immunohistochemistry was applied to detect the expression of Pokemon protein in 92 cases of NSCLC and 20 cases of paracancerous lung tissues.Correlation between abnormal expression of Pokemon with pathologic characteristics and prognosis of NSCLC was analyzed. RESULTS: Pokemon was not expressed in paracancerous lung tissues and was found in 66 of 92(71.7%) cases of lung cancer tissues.Expression of Pokemon was closely related to TNM stages(P=0.011).Survival rate of patients with negative Pokemon expression was significantly higher than that of those with positive Pokemon expression(P=0.0015).Pokemon expression was demonstrated as independent prognostic factor of NSCLC. CONCLUSIONS: Pokemon is expressed in NSCLC and it may be identified as a new diagnostic marker.High expression of Pokemon may indicate poor prognosis of patients with NSCLC.

[mRNA expression of RASSF1A in esophageal squamous cell carcinoma and clinical significance thereof].

OBJECTIVE: To investigate the mRNA expression of the new tumor suppressor gene, RASSF1A, in esophageal squamous cell carcinoma and its biological value. METHODS: Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the mRNA expression of RASSF1A in the tumor tissues, tissues near tumor, and normal tissues, all obtained during operation, from 66 esophageal squamous cell carcinoma patients. RESULTS: The deletion rates of RASSF1A mRNA expression were 42.4% (28/66), 15.2% (10/66), and 0 in the tumor tissues, tissues near tumor, and normal tissues respectively. The deletion rates of RASSF1A mRNA expression in patients with lymph node metastasis was 61.1%, significantly higher than that of the patients without lymph node metastasis (20.0%, chi(2) = 11.323, P < 0.01); The deletion rates of RASSF1A mRNA expression in the esophageal squamous cell carcinoma at the advanced stages (stages III - IV) was 61.5%, significantly higher than that in the esophageal squamous cell carcinoma at the early stages (stages I - II, 30.0%, chi(2) = 6.417, P < 0.01). The deletion rages of RASSF1A mRNA in the highly, moderately, and lowly differentiation tumors were 38.5% (10/26), 38.5% (10/26), and 57.1% (8/14) respectively, However, there was no significant association between the differentiation degree of tumor and the grade the deletion rages of RASSF1A mRNA (chi(2) = 1.576, P = 0.455). CONCLUSION: The deletion of the mRNA expression of RASSF1A, a tumor suppressor gene, may play an important role in the tumorigenesis and influences the prognosis of esophageal squamous cell carcinoma.

[Genescan analysis of non-small cell lung cancer in the long arm of chromosome 6].

OBJECTIVE: To investigate if there are microsatellite loci in the long arm of chromosome 6 that have close relationship with non-small cell lung cancer. METHODS: Multiple PCR approach was used to analyze the 18 loci in the long arm of chromosome 6. The PCR products were analyzed in PAGE, and then the electrophoresis maps were analyzed with Gene Scan(TM) and Genotyper(TM). RESULTS: There were different frequencies of loss of heterozygosity (LOH) in different loci (varying from 3.85% to 38.45%). The total frequency of LOH in 41 gastric cancers was 58.5%(24/41). Eight loci with the LOH frequency higher than 20% were mainly located in 2 regions: 6q24 and 6q27. The accurate location is 6q24-6q25.3 [D6S1699(35%), D6S409(23.33%), D6S441(33.33%)] and 6q26-27 [D6S1550(38.45%), D6S264(20%), D6S1585(25%), D6S446(33.33%), D6S281(30.77%)]. CONCLUSION: There may be tumor suppressor genes located in the region of 6q24 and 6q27, which have close relationship with non-small cell lung cancer.