MYCT1 inhibits the EMT and migration of laryngeal cancer cells via the SP1/miR-629-3p/ESRP2 pathway.

MYCT1 has an inhibitory effect on the migration of laryngeal cancer cells, although the underlying molecular mechanism remains unknown. In this study, we aimed to explore the mechanism of MYCT1 in the epithelial-mesenchymal transition (EMT) and migration of laryngeal cancer cells. We found that MYCT1 significantly decreased the expression of miR-629-3p but increased the expression of ESRP2 in laryngeal cancer cells. The expression of miR-629-3p and ESRP2 in laryngeal cancer tissues showed significantly positive and negative correlations with patient metastasis, respectively. miR-629-3p was confirmed to repress the expression of ESRP2 by targeting its 3'UTR. SP1 was verified to be a direct transcription factor for miR-629-3p and a downstream target of MYCT1. Moreover, MYCT1 inhibited the EMT and migration of laryngeal cancer cells through the SP1/miR-629-3p/ESRP2 pathway. Taken together, our results establish a novel MYCT1 signaling pathway in the EMT and migration of laryngeal cancer cells, thus providing important insights for further studying the pathway in the diagnosis and treatment of laryngeal cancer.

MYCT1 represses apoptosis of laryngeal cancerous cells through the MAX/miR-181a/NPM1 pathway.

MYCT1 is an important gene known to regulate cell viability and apoptosis of laryngeal cancer cells. However, the underlying molecular mechanism remains unclear. Here, we show that MAX enhances the expression of miR-181a by directly binding to its promoter, whereas miR-181a targets NPM1 and suppresses its expression in laryngeal cancer cells. MYCT1 and miR-181a decrease cell viability and colony formation through enhanced apoptosis, whereas NPM1 displays opposite effects in laryngeal cancer cells. Their opposing functions are further supported by the findings (a) that miR-181a is down-regulated, while NPM1 is up-regulated in laryngeal cancer, and (b) that either inhibition of miR-181a or overexpression of NPM1 can revert the pro-apoptotic effects of MYCT1 on laryngeal cancer cells through extracellular and intracellular apoptotic pathways. Our data suggest that MYCT1 may synergistically interact with MAX as a co-transcription factor or a component of MAX transcriptional complex, to transcriptionally regulate the expression of miR-181a, which, in turn, decreases NPM1 expression at post-transcriptional levels, leading to enhanced apoptosis in laryngeal cancer cells. These factors may serve as potential targets for early diagnosis and treatment of laryngeal cancer.

LiCrS2 and LiMnS2 Cathodes with Extraordinary Mixed Electron-Ion Conductivities and Favorable Interfacial Compatibilities with Sulfide Electrolyte.

Sulfide-type solid-state electrolytes for all-solid-state lithium ion batteries are capturing more and more attention. However, the electronegativity difference between the oxygen and the sulfur element makes sulfide-type solid-state electrolytes chemically incompatible with the conventional LiCoO2 cathode. In this work, we proposed a series of chalcopyrite-structured sulfide-type materials and systematically assessed their performances as the cathode materials in all-solid-state lithium ion batteries by first-principle calculations. All the five metallic LiMS2 (M = Cr, Mn, Fe, Co, and Ni) materials are superionic conductors with extremely small lithium ion migration barriers in the range from 43 to 99 meV, much lower than most oxide- and even sulfide-type cathodes. Voltage and volume calculations indicate that only LiCrS2 and LiMnS2 cathodes are structurally stable during cycling with the stable voltage plateaus at ∼3 V, much higher than that of the P3m1-LiTiS2 cathode. For the first time, we studied the interfacial lithium transport resistance from a new perspective of charge transfer and redistribution at the electrode/solid-state electrolyte interface. LiCrS2 and LiMnS2 cathodes exhibit favorable interfacial compatibilities with Li3PS4 electrolyte. Our investigations demonstrate that the metallic LiCrS2 and LiMnS2 superionic conductors would possess excellent rate capability, high energy density, good structural stability during cycling, and favorable interfacial compatibility with Li3PS4 electrolyte in all-solid-state lithium ion batteries.

CREB promotes laryngeal cancer cell migration via MYCT1/NAT10 axis.

PURPOSE: CREB, MYCY1 and NAT10 are involved in cancer cell migration. However, the relationship between these three proteins and their role in laryngeal cancer cell migration remains unknown. METHODS: Transient gene transfection was performed in laryngeal cancer cells. Bioinformatics analysis was used to predict the binding of CREB to MYCT1 promoter. Binding of CREB to the promoter of MYCT1 was monitored by luciferase reporter assay and chromatin immuno-precipitation method in vitro and in vivo, respectively. Real-time RT-PCR and Western bolt were applied to detect gene transcription and translation levels, respectively. Laryngeal cancer cell migration was assayed by transwell chamber experiment. RESULTS: CREB protein expression was significantly up-regulated in laryngeal cancer tissues and associated with cancer differentiation, tumor stage, and lymphatic metastasis. CREB inhibits MYCT1 expression by direct binding to its promoter. Meanwhile, MYCT1 has a negative impact on the NAT10 gene expression. Furthermore, CREB promotes NAT10 expression via down-regulating the MYCT1 gene expression. In addition, contrary to MYCT1, CREB and NAT10 enhanced laryngeal cancer cell migration. MYCT1 and NAT10 significantly rescued the effects of CREB and MYCT1 on Hep2 cell migration, respectively. CONCLUSION: CREB promotes laryngeal cancer cell migration via MYCT1/NAT10 axis, suggesting that CREB might be a potential prognostic marker in laryngeal cancer.

YY1 directly suppresses MYCT1 leading to laryngeal tumorigenesis and progress.

YY1 is a key transcription factor and plays different roles in various cancers. However, role and mechanism of YY1 in laryngeal cancer are still unknown. YY1 and MYCT1 mRNA and protein levels were detected by Real-time RT-PCR and Western Blot methods, respectively. Binding of YY1 to MYCT1 promoter was predicted and confirmed by bioinformatics and chromatin immunoprecipitation assays, respectively. MYCT1 promoter activity was assessed by dual luciferase assay system. Laryngeal cancer cell proliferation, migration, and apoptosis were evaluated by cell viability, colony formation, cell scratch assay, transwell assay, and flow cytometry methods, respectively. YY1 and MYCT1 were upregulated and downregulated at transcriptional level in laryngeal cancer, respectively, which showed a negative correlation between YY1 and MYCT1 expression in laryngeal cancer. Significantly higher expression of YY1 and lower expression of MYCT1 were found in laryngeal cancer tissues of patients with lymphatic metastasis than those without metastasis.YY1 directly bound to MYCT1 promoter region and inhibited its promoter activity. YY1 silence had similar biological functions as MYCT1 overexpression in repressiveness of proliferation and migration, and promotion of apoptosis in laryngeal cancer cells. However, the effects of YY1 silence were recovered by MYCT1 knockdown. YY1 promotes proliferation and migration with suppression of apoptosis via directly inhibiting MYCT1 in laryngeal cancer cells, suggesting that YY1 is a useful target as a potential oncogene in laryngeal cancer development and progression.

Transcriptional suppression of microRNA-27a contributes to laryngeal cancer differentiation via GSK-3ß-involved Wnt/ß-catenin pathway.

miR-27a regulates cell differentiation in a variety of diseases. However, whether and how miR-27a participates in laryngeal cancer cell differentiation remains unknown. Therefore, we explored role and molecular mechanism of miR-27a in laryngeal cancer differentiation in the study. We found that miR-27a expression was inversely correlated with laryngeal cancer differentiation degree based on the clinical pathological diagnosis of each patient. miR-27 asignificantly rescued differentiation and inhibited ß-catenin, LEF1, OCT4 and SOX2 in Wnt/ß-catenin pathway in all-trans-retinoic acid (ATRA)-induced laryngeal cancer cells. Bindings of RARα to miR-27a and miR-27a to GSK-3ß were confirmed by ChIP and Luciferase reporter assays, respectively. In conclusion, miR-27a is a negative regulator in laryngeal cancer differentiation. RARα-mediated miR-27a transcriptional inactivation releases the inhibition of miR-27a on GSK-3ß leading to laryngeal cancer differentiation through GSK-3ß-involved Wnt/ß-catenin pathway, suggesting that miR-27a is a usefully therapeutic target at least in ATRA-induced laryngeal cancer differentiation.

Association between vitamin D and development of otitis media: A PRISMA-compliant meta-analysis and systematic review.

BACKGROUND: Nutrients related to serum vitamin D level were previously shown to be significantly associated with the risk of many chronic diseases. This study aimed to assess potential relationships between serum vitamin D level and otitis media (OM) risk. METHODS: PubMed, EMBASE, and Cochrane Library databases were searched till Aug 18, 2015 for studies of quantitative OM risk estimates in relation to serum vitamin D level. The odds ratio and weighted mean difference, with 95% confidence intervals (CIs), were used to measure the relationship between serum vitamin D level and OM risk. RESULTS: Of the 89 articles identified by database search, 5 studies reported data of 16,689 individuals were included in our meta-analysis. We noted participants with OM was associated with lower level of plasma vitamin D when compared with patients without OM (weighted mean difference -5.67; 95% CI -8.08 to -3.26, P < 0.001). Furthermore, as compared with control group, serum vitamin D level was not associated with the risk of OM (odds ratio 0.80, 95% CI 0.47-1.38, P = 0.425). Subgroup analyses suggested that participants with acute OM might associate with lower serum vitamin D level. CONCLUSIONS: Plasma vitamin D level might play an important role on the progression of acute OM, whereas no significant impact in patients with chronic OM.

Methylation Status of SP1 Sites within miR-23a-27a-24-2 Promoter Region Influences Laryngeal Cancer Cell Proliferation and Apoptosis.

DNA methylation plays critical roles in regulation of microRNA expression and function. miR-23a-27a-24-2 cluster has various functions and aberrant expression of the cluster is a common event in many cancers. However, whether DNA methylation influences the cluster expression and function is not reported. Here we found a CG-rich region spanning two SP1 sites in the cluster promoter region. The SP1 sites in the cluster were demethylated and methylated in Hep2 cells and HEK293 cells, respectively. Meanwhile, the cluster was significantly upregulated and downregulated in Hep2 cells and HEK293 cells, respectively. The SP1 sites were remethylated and the cluster was significantly downregulated in Hep2 cells into which methyl donor, S-adenosyl-L-methionine, was introduced. Moreover, S-adenosyl-L-methionine significantly increased Hep2 cell viability and repressed Hep2 cell early apoptosis. We also found that construct with two SP1 sites had highest luciferase activity and SP1 specifically bound the gene cluster promoter in vitro. We conclude that demethylated SP1 sites in miR-23a-27a-24-2 cluster upregulate the cluster expression, leading to proliferation promotion and early apoptosis inhibition in laryngeal cancer cells.

Upregulation of microRNA-23a regulates proliferation and apoptosis by targeting APAF-1 in laryngeal carcinoma.

MicroRNA-23a (miR-23a) is a potential biomarker for laryngeal cancer. Apoptotic protease activating factor 1 (APAF-1) was recently demonstrated to be a target of miR-23a. However, whether miR-23a exerts its effects via APAF-1 in laryngeal cancer, remains unknown. In the present study, miR-23a expression was detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). APAF-1 mRNA and protein expression levels were assayed by RT-qPCR and western blotting, respectively. Binding of miR-23a to APAF-1 was monitored by a luciferase reporter assay. Gain-of-function and loss-of-function studies were performed in order to investigate the roles of miR-23a and APAF-1 in Hep2 cell proliferation and apoptosis. miR-23a and APAF-1 were found to be significantly upregulated and downregulated, respectively, in laryngeal cancer tissues, and there was a significant negative correlation between APAF-1 and miR-23a expression. The results of the luciferase reporter assay demonstrated that miR-23a bound directly to the APAF-1 mRNA 3'-untranslated region. Ectopic expression of miR-23a and knockdown of APAF-1 significantly promoted cell proliferation and colony formation, and inhibited early apoptosis in Hep2 cells. In conclusion, miR-23a acts as an oncogenic regulator in laryngeal carcinoma by directly targeting APAF-1, and may be a useful biomarker in the diagnosis and treatment of laryngeal carcinoma.

MicroRNA-27a promotes proliferation and suppresses apoptosis by targeting PLK2 in laryngeal carcinoma.

BACKGROUND: miRNA-27a has been confirmed as an important regulator in carcinogenesis and other pathological processes. Whether and how it plays a role in the laryngeal carcinoma is unknown. METHODS: Mature miRNA-27a expression in laryngeal cancer was detected by qRT-PCR. Gain-of-function studies using mature miR-27a were performed to investigate cell proliferation and apoptosis in the Hep2 cells. In silico database analysis and luciferase reporter assay were applied to predict and validate the direct target, respectively. Loss-of-function assays were performed to investigate the functional significance of the miR-27a target gene. qRT-PCR and Western blot were used to evaluate mRNA and protein levels of the target, respectively. RESULTS: miR-27a was significantly up-regulated in the laryngeal tumor tissues compared to the adjacent non-tumor tissues. In silico database analysis result revealed that PLK2 is a potential target of miR-27a. luciferase reporter assay result showed the direct inhibition of miR-27a on PLK2-3'UTR. In the cases with miR-27a up-regulation, PLK2 protein expression level was significantly lower in cancer tissues than that in the adjacent non-tumor tissues, which showed a negative correlation with miR-27a expression level. Both miR-27a and knockdown of PLK2 caused the increase of the cell viability and colony formation and inhibition of the late apoptosis in the Hep2 cell lines. Moreover, miR-27a but not PLK2 also repressed the early apoptosis in the Hep2 cells. Additionally, no alteration of the Hep2 cell cycle induced by miR-27a was detected. CONCLUSIONS: miR-27a acts as an oncogene in laryngeal squamous cell carcinoma through down-regulation of PLK2 and may provide a novel clue into the potential mechanism of LSCC oncogenesis or serve as a useful biomarker in diagnosis and therapy in laryngeal cancer.

S100A4 is upregulated via the binding of c-Myb in methylation-free laryngeal cancer cells.

DNA hypomethylation is correlated with the overexpression of the S100A4 gene in several types of cancers including laryngeal cancer, but the molecular mechanism is unknown. We speculated that the methylation status of the promoter affects its binding to the corresponding transcription factors. In the present study, luciferase reporter assay results indicated that the sequences -485 - +73 and -486 - -530 of the S100A4 promoter may harbor the positive and negative cis-acting elements, respectively; and moreover, the luciferase activity promoted by the sequence -485 - +73 increased and the S100A4 gene was significantly upregulated in 5-Aza-induced HEp2 cells. This implies that the methylation status of the sequence is important in regulating the expression of S100A4. Four transcription factor binding motifs including c-Myb, C/EBpα, Ap2 and Msx-1 in the region were predicted by P-Match software. c-Myb and C/EBpα but not Ap2 and Msx-1 were confirmed by EMSA and ChIP as transcription factors of S100A4. The decreased luciferase activity in methylation-free HEp2 cells transfected by the mutant c-Myb motif related to the methylated cytosine suggests that the hypomethylation of the c-Myb motif upregulates the S100A4 expression in laryngeal cancer.

MYCT1-TV, a novel MYCT1 transcript, is regulated by c-Myc and may participate in laryngeal carcinogenesis.

BACKGROUND: MYCT1, a putative target of c-Myc, is a novel candidate tumor suppressor gene cloned from laryngeal squamous cell carcinoma (LSCC). Its transcriptional regulation and biological effects on LSCC have not been clarified. METHODOLOGY/PRINCIPAL FINDINGS: Using RACE assay, we cloned a 1106 bp transcript named Myc target 1 transcript variant 1 (MYCT1-TV) and confirmed its transcriptional start site was located at 140 bp upstream of the ATG start codon of MYCT1-TV. Luciferase, electrophoretic mobility shift and chromatin immunoprecipitation assays confirmed c-Myc could regulate the promoter activity of MYCT1-TV by specifically binding to the E-box elements within -886 to -655 bp region. These results were further verified by site-directed mutagenesis and RNA interference (RNAi) assays. MYCT1-TV and MYCT1 expressed lower in LSCC than those in paired adjacent normal laryngeal tissues, and overexpression of MYCT1-TV and MYCT1 could inhibit cell proliferation and invasion and promote apoptosis in LSCC cells. CONCLUSIONS/SIGNIFICANCE: Our data indicate that MYCT1-TV, a novel MYCT1 transcript, is regulated by c-Myc and down-regulation of MYCT1-TV/MYCT1 could contribute to LSCC development and function.

The involvement of CHD5 hypermethylation in laryngeal squamous cell carcinoma.

Chromodomain helicase DNA-binding protein 5 (CHD5) has been found to be a candidate tumor suppressor gene (TSG) in malignant neural tumors. In mice heterozygous for chd5 deficiency, the first tumor observed was pathological squamous cell carcinoma. More than 95% of primary laryngeal cancer is squamous cell carcinoma. Thus, we explored the expression of CHD5 in 65 patients with laryngeal squamous cell carcinoma (LSCC) using real-time PCR, immunohistochemistry and Western blotting. DNA methylation was detected using bisulfate-specific sequencing. The potential function of CHD5 was determined using MTT, apoptosis and transwell migration assays in CHD5-transfected Hep-2 cells. Our results revealed that the mRNA and protein expression levels of CHD5 in LSCC tissues were significantly lower than those in clear surgical margin tissues (p<0.05), and there is a significant correlation between the mRNA and protein expression levels of CHD5 (p<0.01). In addition, there were significant differences in CHD5 mRNA and protein levels with respect to the patient's clinical stage (p<0.05). Aberrant methylation of the CHD5 promoter was frequently found in the Hep-2 cell line and LSCC tumor tissues, especially tumor tissues from advanced TNM (p<0.05) or older patients (p<0.05). Finally, ectopic expression of CHD5 in laryngeal cancer cells led to significant inhibition of growth and invasiveness. Our data suggest that CHD5 is a tumor suppressor gene that is epigenetically downregulated in LSCC.

14-3-3epsilon contributes to tumour suppression in laryngeal carcinoma by affecting apoptosis and invasion.

BACKGROUND: 14-3-3epsilon regulates a wide range of biological processes, including cell cycle control, proliferation, and apoptosis, and plays a significant role in neurogenesis and the formation of malignant tumours. However, the exact function and regulatory mechanism of 14-3-3epsilon in carcinogenesis have not been elucidated. METHODS: The expression of 14-3-3epsilon was assessed by RT-PCR and western blotting. The invasiveness and viability of Hep-2 cells were determined by the transwell migration assay and MTT assay, respectively. Cell cycle and apoptosis of Hep-2 cells were detected by flow cytometry. RESULTS: The mRNA and protein expression of 14-3-3epsilon in larynx squamous cell carcinoma (LSCC) tissues were significantly lower than those in clear surgical margin tissues. Statistical analysis showed that the 14-3-3epsilon protein level in metastatic lymph nodes was lower than that in paired tumour tissues. In addition, the protein level of 14-3-3epsilon in stage III or IV tumours was significantly lower than that in stage I or II tumours. Compared with control Hep-2 cells, the percentages of viable cells in the 14-3-3epsilon-GFP and negative control GFP groups were 36.68 +/- 14.09% and 71.68 +/- 12.10%, respectively. The proportions of S phase were 22.47 +/- 3.36%, 28.17 +/- 3.97% and 46.15 +/- 6.82%, and the apoptotic sub-G1 populations were 1.23 +/- 1.02%, 2.92 +/- 1.59% and 13.72 +/- 3.89% in the control, negative control GFP and 14-3-3epsilon-GFP groups, respectively. The percentages of the apoptotic cells were 0.84 +/- 0.25%, 1.08 +/- 0.24% and 2.93 +/- 0.13% in the control, negative control GFP and 14-3-3epsilon-GFP groups, respectively. The numbers of cells that penetrated the filter membrane in the control, negative control GFP and 14-3-3epsilon-GFP groups were 20.65 +/- 1.94, 17.63 +/- 1.04 and 9.1 +/- 0.24, respectively, indicating significant differences among the different groups. CONCLUSIONS: Decreased expression of 14-3-3epsilon in LSCC tissues contributes to the initiation and progression of LSCC. 14-3-3epsilon can promote apoptosis and inhibit the invasiveness of LSCC.

Dynamics of spherical metallic particles in cylinder electrostatic separators/purifiers.

This paper presents a theoretical analysis of the dynamics of spherical metallic particles in electrostatic separators/purifiers (ESPs). The particle equations of motion are numerically solved in two dimensions using a computational algorithm. The ESPs consist of a pair of conductor cylinder electrodes. The upper cylinder is energized by HVdc, while the lower one is grounded and fixed horizontally on a revolvable axis. Some phenomena and aspects of separation process are explained and depicted including lifting off, impact, "motion collapse" and "sudden bouncing". The results reveal that the several phenomena depend on initial position, radius and density of the particle, curvature of the cylinder electrodes, distance between the electrodes and amplitude of the applied voltage. Optimization of the parameters is presented in order to get better separation/purification processes.

[The investigation of STK15 gene amplification and overexpression in laryngeal squamous cell carcinoma].

OBJECTIVE: To investigate the role of STK15 gene amplification and overexpression to genesis and development of laryngeal squamous cell carcinoma (LSCC). METHODS: STK15 gene amplification in 40 cases carcinoma tissues and normal tissues as control was detected by differential PCR approach. STK15 mRNA and protein levels were evaluated by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry method. RESULTS: In 40 LSCC cases, STK15 gene amplification was found in 14 tumor tissues(35%), mRNA overexpression in 27 tumor tissues(67.5%), and protein upregulated in 29 tumor tissues(72.5%). Statistics analysis showed that STK15 gene amplification and mRNA overexpression were obviously associated to differentiation degree of LSCC, and protein overexpression was closely associated with both differentiation degree and pathological grades of LSCC. CONCLUSION: This research results suggest that STK15 gene amplification contributes to its mRNA and protein overexpression through affecting the exact replication of centrosome and separation of chromosomes. STK15 gene thus plays a role in LSCC oncogenesis and malignant progression.

Average-12.9 chromosome imbalances coupling with 15 differential expression genes possibly involved in the carcinogenesis, progression and metastasis of supraglottic laryngeal squamous cell cancer.

OBJECTIVE: With the objective of discovering novel putative chromosomal regions and special genes involved in the carcinogenesis, progression and metastasis of laryngeal squamous cell cancer (LSCC). METHODS: DNA copy profile of LSCC were obtained and analyzed by comparative genomic hybridization (CGH) and a computerized digital image analysis system. cDNA microarray of LSCC was performed and the profile was analyzed by Hierarchical clustering. RESULTS: CGH analysis showed average-12.9 gains and losses of chromosomes in LSCC. Relatively high frequencies of gains were found at 3q15-21 (14/18), 5p12-13 (11/18), 8q22-24 (6/18), 11q12-13 (8/18), 15q21-23 (7/18) and 18p11 (8/18), while those of losses at 1p13-21 (8/18), 3p21-23 (14/18), 5q21-22 (14/18), 9p12-pter (11/18) and 13q21-31 (8/18). Hierarchical clustering analysis showed that the differentially expressed genes were segregated into three groups. Three genes differentially expressed in process I (normal tissue to cancer) and process II (cancer to lymph node metastasis), and the Cy5/Cy3 ratios of twelve genes were either higher than 5.0 or lower than 0.2 in process I or process II. The fifteen special genes were first reported possibly to be the relationships with LSCC. In particular, 4 genes of them, which were cytochrome C oxidase Va, PPBP, EPHX2 and PON1, were first reported to correlate with tumorigenesis. SH3GL2, which was one of the 15 special genes, was located at one of the special chromosome regions, 9p12-pter. CONCLUSION: The important genes and special chromosomal aberrances might provide us a clue for further investigation of carcinogenesis, progression and metastasis in LSCC.

[Mutation of p53 and overexpression of STK15 in laryngeal squamous-cell carcinoma].

OBJECTIVE: To explore the relationship between p53 gene mutations and STK15 abnormal expression in the development of human laryngeal squamous-cell carcinoma (LSCC). METHODS: LSCC tissues and matched normal tissues were taken during operation from 55 patients without previous chemotherapy or radiotherapy. Following polymerase chain reaction amplification direct sequencing single strand conformational polymorphism (PCR-SSCP) combined with silver staining were used to detect mutations of p53 gene in exons 7 and 8 (p53E7 and p53E8) using genomic DNA from 110 specimens including 55 LSCC tissues and 55 matched normal tissues. STK15 expression were evaluated by RT-PCR with beta-actin as internal control. RESULTS: The mutation rate of p53E7 was 30.9% (compared to normal tissues, chi(2) = 8.66, P < 0.01). There was no mutation in p53E8. In 38 of the 55 cases (69.1%), the STK15 mRNA expression level was higher than that of the paired normal tissue. The STK15 to beta-actin ratio of average density value was 1.22 +/- 0.49 in the cancer tissue, and 0.99 +/- 0.54 in the normal tissues (t = 4.539, P < 0.01). In 14 of the 17 cases (82.4%) with p53E7 mutations, the STK15 expression was higher than that of normal tissue. In the 38 cases with STK15 over-expression, p53E7 mutation was found in 14 cases (36.8%). The rate of concurrence of p53E gene mutations and STK15 over-expression (25.5%) was higher than that of only p53E gene mutations (chi(2) = 26.025, P < 0.01). CONCLUSION: There is significant association between p53 gene mutation and STK15 over-expression in laryngeal squamous-cell carcinoma.

[Comparative genomic hybridization analysis of laryngeal carcinoma].

In order to find out the genes involved in the tumorigenesis of laryngeal carcinoma, we analyzed 18 laryngeal carcinoma with comparative genomic hybridization. Results show that each one has different degree of variances, included gains and losses of partial and whole chromosome. Each case has 12.9 abnormal regions averagely; losses are more than gains, equal to 7.2 and 5.7 per case respectively. Main regions are gains in chromosomes 3q (78%), 5p (61%), 11q (56%), 1q (50%), 8p (44%), 8q (39%) and 15q (39%), and losses of 3p (70%), 5q (78%), 9p (67%), 13q (50%), 1p (44%) and 14q (39%). There are many specific gains and losses in several chromosomes,especially the increase of copy number karyotype in 1p13-21(8/18), 3p21-23 (14/18), 5p21-22 (14/18), 9p12-pter (10/18) and 13q21-31 (8/18), while the decrease in 1q11-21 (11/18), 3q15-21 (12/18), 8p22-24 (6/18), 11q12-13 (8/18), 15q21-23 (7/18), 18p11 (8/18) are the characteristic varieties. These results suggest that there are oncogene, tumor suppressor gene and other associated genes involved in the tumorigenesis.

[Association of homozygous deletion of p15 and p16 gene and amplification of EGFR gene in laryngeal squamous cell carcinoma].

To assess the relationship of deletion of p15 and p16 gene and EGFR gene amplification in laryngeal squamous cell carcinoma (LSCC). DNA was extracted from fresh tumor. Deletion of p15 exon 2(p15E2) and p16 exon 2(p16E2) in 30 cases of LSCC was detected by polymerase chain reaction (PCR) technique. Amplification of EGFR gene in 30 cases of LSCC was detected by FISH. The rate of p15E2 deletion in 30 cases was 13.3(4/30), and that of p16E2 was 16.7% (5/30). p15E2 and p16E2 codeletion rate was 6.7% (2/30). The rate of EGFR gene amplification in 30 cases was 30% (9/30), and was amplified 2 to 8 fold. Homozygous deletion of p16E2 and p15E2 and codeletion is related with amplification of EGFR gene (P = 0.000018), and may play an important role to oncogenesis and malignant progression in LSCC.