A single nucleotide polymorphism in the Epstein-Barr virus genome is strongly associated with a high risk of nasopharyngeal carcinoma / 癌症

<p><b>BACKGROUND</b>Epstein-Barr virus (EBV) commonly infects the general population and has been associated with nasopharyngeal carcinoma (NPC), which has a high incidence in certain regions. This study aimed to address how EBV variations contribute to the risk of NPC.</p><p><b>METHODS</b>Using logistic regression analysis and based on the sequence variations at EBV-encoded RPMS1, a multi-stage association study was conducted to identify EBV variations associated with NPC risk. A protein degradation assay was performed to characterize the functional relevance of the RPMS1 variations.</p><p><b>RESULTS</b>Based on EBV-encoded RPMS1 variations, a single nucleotide polymorphism (SNP) in the EBV genome (locus 155391: G>A, named G155391A) was associated with NPC in 157 cases and 319 healthy controls from an NPC endemic region in South China [P < 0.001, odds ratio (OR) = 4.47, 95% confidence interval (CI) 2.71-7.37]. The results were further validated in three independent cohorts from the NPC endemic region (P < 0.001, OR = 5.20, 95% CI 3.18-8.50 in 168 cases vs. 241 controls, and P < 0.001, OR = 5.27, 95% CI 4.06-6.85 in 726 cases vs. 880 controls) and a non-endemic region (P < 0.001, OR = 7.52, 95% CI 3.69-15.32 in 58 cases vs. 612 controls). The combined analysis in 1109 cases and 2052 controls revealed that the SNP G155391A was strongly associated with NPC (P(combined) < 0.001, OR = 5.27, 95% CI 4.31-6.44). Moreover, the frequency of the SNP G155391A was associated with NPC incidence but was not associated with the incidences of other EBV-related malignancies. Furthermore, the protein degradation assay showed that this SNP decreased the degradation of the oncogenic RPMS1 protein.</p><p><b>CONCLUSIONS</b>Our study identified an EBV variation specifically and significantly associated with a high risk of NPC. These findings provide insights into the pathogenesis of NPC and strategies for prevention.</p>

Air pollution: a smoking gun for cancer / 癌症

Once considered a taboo topic or stigma, cancer is the number one public health enemy in the world. Once a product of an almost untouchable industry, tobacco is indisputably recognized as a major cause of cancer and a target for anticancer efforts. With the emergence of new economic powers in the world, especially in highly populated countries such as China, air pollution has rapidly emerged as a smoking gun for cancer and has become a hot topic for public health debate because of the complex political, economic, scientific, and technologic issues surrounding the air pollution problem. This editorial and the referred articles published in this special issue of the Chinese Journal of Cancer discuss these fundamental questions. Does air pollution cause a wide spectrum of cancers? Should air pollution be considered a necessary evil accompanying economic transformation in developing countries? Is an explosion of cancer incidence coming to China and how soon will it arrive? What must be done to prevent this possible human catastrophe? Finally, the approaches for air pollution control are also discussed.

Centrifugation: an important pre-analytic procedure that influences plasma microRNA quantification during blood processing / 癌症

Circulating microRNAs are robustly present in plasma or serum and have become a research focus as biomarkers for tumor diagnosis and prognosis. Centrifugation is a necessary procedure for obtaining high-quality blood supernatant. Herein, we investigated one-step and two-step centrifugations, two centrifugal methods routinely used in microRNA study, to explore their effects on plasma microRNA quantification. The microRNAs obtained from one-step and two-step centrifugations were quantified by microarray and TaqMan-based real-time quantitative polymerase chain reaction (Q-PCR). Dynamic light scattering was performed to explore the difference underlying the two centrifugal methods. The results from the microarray containing 1,347 microRNAs showed that the signal detection rate was greatly decreased in the plasma sample prepared by two-step centrifugation. More importantly, the microRNAs missing in this plasma sample could be recovered and detected in the precipitate generated from the second centrifugation. Consistent with the results from microarray, a marked decrease of three representative microRNAs in two-step centrifugal plasma was validated by Q-PCR. According to the size distribution of all nanoparticles in plasma, there were fewer nanoparticles with size >1,000 nm in two-step centrifugal plasma. Our experiments directly demonstrated that different centrifugation methods produced distinct quantities of plasma microRNAs. Thus, exosomes or protein complexes containing microRNAs may be involved in large nanoparticle formation and may be precipitated after two-step centrifugation. Our results remind us that sample processing methods should be first considered in conducting research.

The propensity for tumorigenesis in human induced pluripotent stem cells is related with genomic instability / 癌症

The discovery of induced pluripotent stem cells(iPSCs) is a promising advancement in the field of regenerative medicine. Previous studies have indicated that the teratoma-forming propensity of iPSCs is variable; however, the relationship between tumorigenic potential and genomic instability in human iPSCs (HiPSCs) remains to be fully elucidated. Here, we evaluated the malignant potential of HiPSCs by using both colony formation assays and tumorigenicity tests. We demonstrated that HiPSCs formed tumorigenic colonies when grown in cancer cell culture medium and produced malignancies in immunodeficient mice. Furthermore, we analyzed genomic instability in HiPSCs using whole-genome copy number variation analysis and determined that the extent of genomic instability was related with both the cells' propensity to form colonies and their potential for tumorigenesis. These findings indicate a risk for potential malignancy of HiPSCs derived from genomic instability and suggest that quality control tests, including comprehensive tumorigenicity assays and genomic integrity validation, should be rigorously executed before the clinical application of HiPSCs. In addition, HiPSCs should be generated through the use of combined factors or other approaches that decrease the likelihood of genomic instability.

Ex vivo expansion of tumor-infiltrating lymphocytes from nasopharyngeal carcinoma patients for adoptive immunotherapy / 癌症

Establishing Epstein-Barr virus(EBV)-specific cytolytic T lymphocytes(EBV-CTLs) from peripheral blood mononuclear cells(PBMCs) for adoptive immunotherapy has been reported in EBV-associated malignancies including Hodgkin's lymphoma and nasopharyngeal carcinoma(NPC). In the current study, we performed ex vivo expansion of tumor-infiltrating lymphocytes(TILs) obtained from NPC biopsy specimens with a rapid expansion protocol using anti-CD3 monoclonal antibody(OKT3), recombinant human interleukin(IL)-2, and irradiated PBMCs from healthy donors to initiate the growth of TILs. Young TIL cultures comprised of more than 90% of CD3+ T cells, a variable percentage of CD3+CD8+ and CD3+CD4+ T cells, and less than 10% of CD3-CD16+ natural killer cells, a similar phenotype of EBV-CTL cultures from PBMCs. Interestingly, TIL cultures secreted high levels of the Th1 cytokines, interferon gamma (IFNγ) and tumor necrosis factor-alpha (TNF-α), and low levels of the Th2 cytokines, IL-4 and IL-10. Moreover, young TILs could recognize autologous EBV-transformed B lymphoblast cell lines, but not autologous EBV-negative blast cells or allogeneic EBV-negative tumor cells. Taken together, these data suggest that ex vivo expansion of TILs from NPC biopsy tissue is an appealing alternative method to establish T cell-based immunotherapy for NPC.

Repressing malic enzyme 1 redirects glucose metabolism, unbalances the redox state, and attenuates migratory and invasive abilities in nasopharyngeal carcinoma cell lines / 癌症

A large amount of nicotinamide adenine dinucleotide phosphate (NADPH) is required for fatty acid synthesis and maintenance of the redox state in cancer cells. Malic enzyme 1(ME1)-dependent NADPH production is one of the three pathways that contribute to the formation of the cytosolic NADPH pool. ME1 is generally considered to be overexpressed in cancer cells to meet the high demand for increased de novo fatty acid synthesis. In the present study, we found that glucose induced higher ME1 activity and that repressing ME1 had a profound impact on glucose metabolism of nasopharyngeal carcinoma(NPC) cells. High incorporation of glucose and an enhancement of the pentose phosphate pathway were observed in ME1-repressed cells. However, there were no obvious changes in the other two pathways for glucose metabolism: glycolysis and oxidative phosphorylation. Interestingly, NADPH was decreased under low-glucose condition in ME1-repressed cells relative to wild-type cells, whereas no significant difference was observed under high-glucose condition. ME1-repressed cells had significantly decreased tolerance to low-glucose condition. Moreover, NADPH produced by ME1 was not only important for fatty acid synthesis but also essential for maintenance of the intracellular redox state and the protection of cells from oxidative stress. Furthermore, diminished migration and invasion were observed in ME1-repressed cells due to a reduced level of Snail protein. Collectively, these results suggest an essential role for ME1 in the production of cytosolic NADPH and maintenance of migratory and invasive abilities of NPC cells.

GWAS signals across the HLA regions: revealing a clue for common etiology underlying infectious tumors and other immunity diseases / 癌症

Increasing evidence suggests that multiple genes in the human leukocyte antigen(HLA) regions play an important role in development of cancers and immunity disorders. However, the biological mechanisms of the HLA associations are not well understood. We recently conducted a survey of all genome-wide association studies (GWAS) with significant findings in the HLA regions and concluded that diseases such as cancer and immune disorders are more likely to be associated with genetic variants located in the HLA regions than other diseases. This finding is suggestive for testing a hypothesis of a common etiology of infectious tumors and other immunity diseases.

Correlation of Skp2 overexpression to prognosis of patients with nasopharyngeal carcinoma from South China / 癌症

S-phase kinase-associated protein 2 (Skp2), which plays a role in cell cycle regulation, is commonly overexpressed in a variety of human cancers and associated with poor prognosis. However, its role in nasopharyngeal carcinoma (NPC) is not well understood. In this study, we examined the clinical significance of Skp2, with a particular emphasis on overall survival (OS) and disease-free survival (DFS), in NPC cases in South China, where NPC is an epidemic. Additionally, we explored the function of Skp2 in maintaining a cancer stem cell-like phenotype in NPC cell lines. Skp2 expression was assessed for 127 NPC patients using tissue microarrays and immunohistochemistry and analyzed together with clinicopathologic features, OS, and DFS. Skp2 expression was detectable, or positive, in 75.6% of patients. Although there was no correlation between Skp2 and any clinicopathologic factor, Skp2 expression significantly portended inferior OS (P = 0.013) and DFS (P = 0.012). In the multivariate model, Skp2 expression remained significantly predictive of poor OS [P = 0.009, risk ratio (RR) = 4.06] and DFS (P = 0.008, RR = 3.56), and this was also true for clinical stage (P = 0.012 and RR=3.201 for OS; P = 0.002 and RR=1.94 for DFS) and sex (P = 0.016 and RR=0.31 for OS; P = 0.006 and RR = 0.27 for DFS). After Skp2 knockdown, a colony formation assay was used to evaluate the self-renewal property of stem-like cells in the NPC cell lines CNE-1 and CNE-2. The colony formation efficiency in CNE-1 and CNE-2 cells was decreased. In Skp2-transfected CNE-1 and CNE-2 cells, side population (SP) proportion was increased as detected by flow cytometry. Skp2 is an independent prognostic marker for OS and DFS in NPC. Skp2 may play a role in maintaining the cancer stem cell-like phenotype of NPC cell lines.

Apogossypolone targets mitochondria and light enhances its anticancer activity by stimulating generation of singlet oxygen and reactive oxygen species / 癌症

Apogossypolone (ApoG2), a novel derivative of gossypol, has been shown to be a potent inhibitor of antiapoptotic Bcl-2 family proteins and to have antitumor activity in multiple types of cancer cells. Recent reports suggest that gossypol stimulates the generation of cellular reactive oxygen species (ROS) in leukemia and colorectal carcinoma cells; however, gossypol-mediated cell death in leukemia cells was reported to be ROS-independent. This study was conducted to clarify the effect of ApoG2-induced ROS on mitochondria and cell viability, and to further evaluate its utility as a treatment for nasopharyngeal carcinoma (NPC). We tested the photocytotoxicity of ApoG2 to the poorly differentiated NPC cell line CNE-2 using the ROS-generating TL/10 illumination system. The rapid ApoG2-induced cell death was partially reversed by the antioxidant N-acetyl-L-cysteine (NAC), but the ApoG2-induced reduction of mitochondrial membrane potential (MMP) was not reversed by NAC. In the presence of TL/10 illumination, ApoG2 generated massive amounts of singlet oxygen and was more effective in inhibiting cell growth than in the absence of illumination. We also determined the influence of light on the anti-proliferative activity of ApoG2 using a CNE-2-xenograft mouse model. ApoG2 under TL/10 illumination healed tumor wounds and suppressed tumor growth more effectively than ApoG2 treatment alone. These results indicate that the ApoG2-induced CNE-2 cell death is partly ROS-dependent. ApoG2 may be used with photodynamic therapy (PDT) to treat NPC.

Chloroquine enhances the cytotoxicity of topotecan by inhibiting autophagy in lung cancer cells / 癌症

Although the anti-malaria drug chloroquine (CQ) has been shown to enhance chemotherapy and radiation sensitivity in clinical trials, the potential mechanisms underlying this enhancement are still unclear. Here, we examined the relevant mechanisms by which the multipotent CQ enhanced the cytotoxicity of topotecan (TPT). The lung cancer cell line A549 was treated with TPT alone or TPT combined with CQ at non-cytotoxic concentrations. Cell viability was assessed using the MTT assay. The percentage of apoptotic cells and the presence of a side population of cells were both determined by flow cytometry. Autophagy and the expression of Bcl-2 family proteins were examined by Western blotting. The accumulation of YFP-LC3 dots and the formation of acidic vesicular organelles were examined by confocal microscopy. CQ sensitized A549 cells to TPT and enhanced TPT-induced apoptosis in a Bcl-2 family protein-independent fashion. CQ inhibited TPT-induced autophagy, which modified the cytotoxicity of TPT. However, CQ failed to modify the transfer of TPT across the cytoplasmic membrane and did not increase lysosomal permeability. This study showed that CQ at non-cytotoxic concentrations potentiated the cytotoxicity of TPT by interfering with autophagy, implying that CQ has significant potential as a chemotherapeutic enhancer.

A single nucleotide polymorphism in the matrix metalloproteinase 2 promoter is closely associated with high risk of nasopharyngeal carcinoma in Cantonese from southern China / 癌症

Matrix metalloproteinase 2 (MMP2) has been shown to play an important role in several steps of cancer development. The -1306C/T polymorphism of the MMP2 gene displays a strikingly lower promoter activity than the T allele, and the CC genotype in the MMP2 promoter has been reported to associate with the development of several cancers. To assess the contribution of the MMP2 -1306C/T polymorphism to the risk of nasopharyngeal carcinoma (NPC), we conducted a case-control study and analyzed MMP2 genotypes in 370 patients with NPC and 390 frequency-matched controls using real-time PCR-based TaqMan allele analysis. We found that subjects with the CC genotype had an increased risk (OR = 1.55, 95% CI = 1.05-2.27) of developing NPC compared to those with the CT or TT genotypes. Furthermore, we found that the risk of NPC was markedly increased in subjects who were smokers (OR = 15.04, 95% CI = 6.65-33.99), heavy smokers who smoked ≥ 20 pack-years (OR = 18.66, 95% CI = 7.67-45.38), or young (<60 years) at diagnosis (OR = 1.52, 95% CI = 1.01-2.29). Our results provide molecular epidemiological evidence that the MMP2 -1306C/T promoter polymorphism is associated with NPC risk, and this association is especially noteworthy in heavy smokers.

One patient with metastastic colorectal cancer successfully treated by combination of targeted agents after failure of chemotherapy / 癌症

Either cetuximab or bevacizumab can improve the survival of patients with metastastic colorectal cancer (mCRC) if administered combided with cytotoxic agents. However, the effect of two or more target agents in combination is uncertain in these patients. Here, we reported a patient with mCRC successfully treated by a combination of target agents after the failure of chemotherapy. The patient received palliative resection of primary tumor followed by 9 cycles of postoperative XELOX regimen, cytokine-induced killer cell (CIK)-based biotherapy, traditional Chinese medicine, particle implantation in the lung metastatic lesions. The tumor progressed 20 months after the standard treatments. Then, the regimen cetuximab, bevacizumab and cefitinib was applied. During the treatment with targeted agents, grade IV acne-like rash and relatively severe parionychia of the toes occurred. Both of them recovered smoothly. The PET-CT reexamination at 40 days after the target treatment showed that the metabolism of mediastinal lymph nodes basically recovered to a normal level. The combination of multiple targeted agents obtained a progression-free survival(PFS) of 11 months and the patient with a good quality of life during this period.

Comparative study on risk factors and family history of familial and sporadic nasopharyngeal carcinoma patients / 中华预防医学杂志

<p><b>OBJECTIVE</b>To explore the difference between familial and sporadic nasopharyngeal carcinoma patients on risk factors and family history and provide evidence on genetic counseling and screening strategy for relatives of nasopharyngeal carcinoma patients in Guangdong province.</p><p><b>METHODS</b>The Cantonese nasopharyngeal carcinoma patients diagnosed in Cancer Center, Sun Yat-sen University from October, 2005 to October, 2007 were recruited as subjects. 1877 patients were collected, including 181 familial nasopharyngeal carcinoma patients and 1696 sporadic nasopharyngeal carcinoma patients. The demographic characteristics, clinical characteristics, risk factors and family history between two groups were compared. Moreover, the distribution of nasopharyngeal carcinoma patients in first-degree relatives and the time interval between proband and the affected first-degree relatives in familial nasopharyngeal carcinoma patients was analyzed.</p><p><b>RESULTS</b>All 9.64% of 1877 nasopharyngeal carcinoma patients had affected relatives in first-degree relatives, among them, 58.49% (124/212) were siblings and 41.51% (88/212) were parents. The mean time interval between siblings and proband were (7.40 +/- 5.41) years while the mean time interval between parents and proband were (15.55 +/- 10.61) years when nasopharyngeal carcinoma occurred, and the difference was statistically significant (t = -5.78, P < 0.01). More than 80% patients of the two group were at advanced stage when they were diagnosed. There were no difference (P values were all > 0.05) both in adulthood and childhood in salted fish (OR = 1.01; 95% CI: 0.59 - 1.75 vs OR = 1.31; 95% CI: 0.92 - 1.86), preserved vegetables (OR = 0.93; 95% CI: 0.58 - 1.49 vs OR = 1.12; 95% CI: 0.80 - 1.57), fermented pastes (OR = 0.37; 95% CI: 0.14 - 1.01 vs OR = 1.61; 95% CI: 0.99 - 2.48), fresh fruits (OR = 0.87; 95% CI: 0.60 - 1.26 vs OR = 0.65; 95% CI: 0.20 - 2.12) and cured meat (OR = 1.26; 95% CI: 0.87 - 1.83 vs OR = 1.28; 95% CI: 0.71 - 2.30) diet. No significant difference (P > 0.05) was obtained on smoking (OR = 0.99; 95% CI: 0.68 - 1.45) and incidence of other cancers in first-degree relatives (OR = 0.85; 95% CI: 0.56 - 1.28) in the two groups.</p><p><b>CONCLUSION</b>Familial nasopharyngeal carcinoma was 9.64% in the observed subjects. In the familial nasopharyngeal carcinoma, the time interval at diagnosis was shorter between proband and siblings as compared with parents. Most of the patients were at advanced stage. So, we recommend the first-degree relatives of nasopharyngeal carcinoma patients, especially siblings, should be screened regularly according to the specific conditions.</p>

Association of nasopharyngeal carcinoma risk with cytochrome P450 CYP1A1 gene polymorphisms / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the association between CYP1A1 gene polymorphisms and susceptibility of nasopharyngeal carcinoma in Cantonese nuclear families through family-based association study.</p><p><b>METHODS</b>A total of 457 Cantonese nuclear families,consisting of 2134 members, were recruited as subjects. Each family included two parents and at least one offspring with nasopharyngeal carcinoma. Two single nucleotide polymorphisms (SNP) in CYP1A1 named m1 (rs4646903) and m2 (rs1048943), were genotyped by PCR-RFLP assay and verified by directly sequencing. The genotype data were analyzed with family-based association test (FBAT) software to check the linkage and association between the two genetic markers and susceptibility of nasopharyngeal carcinoma.</p><p><b>RESULTS</b>FBAT analysis showed that the minor allele frequencies (MAF) of the two SNP were 0.442 (C) and 0.339 (G) respectively. For m1 polymorphism in CYP1A1 gene was not significantly associated with nasopharyngeal carcinoma in our study population whether stratified with VCA-IgA or not (without stratification: chi2 = 2.399, P = 0.301; with stratification: low-titer group (VCA-IgA <1:80), MAF = 0.457 (C), chi2 = 1.221, P = 0.543; high-titer group (VCA-IgA > or = 1:80), MAF = 0.427 (C), chi2 =2.832, P = 0.243) . For m2 polymorphism, when VCA-IgA <1:80, the G allele showed decreased transmission under additive and dominant model (MAF = 0.347 (G); Zadditive = -2.120, Padditive = 0.034; Zdominant = - 2.303, Pdominant = 0.021) and a boundary P value was got with global statistic (chi2 = 5.394, P = 0.067) . Haplotype TG (0.057), constructed by m1 and m2, might decrease nasopharyngeal carcinoma risk (Z= -2.002, P=0.045). A boundary P value was also got with global statistic (chi2 =7.067, P=0.070).</p><p><b>CONCLUSION</b>There was no statistical significance between m1 polymorphism and susceptibility of nasopharyngeal carcinoma in Cantonese nuclear families. And this study showed that m2 polymorphism might associated with the decrease of nasopharyngeal carcinoma in Cantonese nuclear families.</p>

Loss of heterozygosity in the region of chromosome 4p15.1-4q12 in nasopharyngeal carcinoma patients with familial history / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze the allelic loss of heterozygosity (LOH) in the region of chromosome 4p15.1-4q12 in nasopharyngeal carcinoma (NPC) patients with family history.</p><p><b>METHODS</b>Tumor cells and lymphocytes were obtained from paraffin-embedded biopsied tissue section by microdissection. LOH detections were carried out on 25 NPC patients with family history by PCR-based microsatellite polymorphism analysis using 7 pairs of microsatellite markers primers. The microsatellite loci located in 4p15.1-4q12 region. Genescan software was used to analyse LOH at each locus.</p><p><b>RESULTS</b>Ninety-two percent of NPC cases (23/25) with family history was showed at least one microsatellite marker of LOH. Higher frequencies of LOH were found at three loci: D4S238 (56%), D4S350 (50%), D4S1547 (50%). The minimal common region of deletion might be defined between D4S350 and D4S1547.</p><p><b>CONCLUSION</b>The higher incidence of LOH at D4S350 and D4S1547 suggests that there may be a potential tumor suppressor gene located in the two regions.</p>

Family-based association study of XRCC1 gene polymorphisms in nasopharyngeal carcinoma / 中华预防医学杂志

<p><b>OBJECTIVE</b>To test the association between XRCC1 gene polymorphisms and susceptibility of nasopharyngeal carcinoma in Cantonese nuclear families through a family-based association study.</p><p><b>METHODS</b>A total of 2134 study subjects from 457 Cantonese nuclear families were recruited in the study. Each family had two parents and at least one offspring with nasopharyngeal carcinoma. Genotyping for three single nucleotide polymorphisms in XRCC1 gene, including rs1799782 (C > T), rs25489 (G > A) and rs25487 (G > A), were performed with PCR-RFLP assay. The genotype data were analyzed with family-based association test (FBAT) software to check linkage and association between the three genetic markers and susceptibility of nasopharyngeal carcinoma.</p><p><b>RESULTS</b>FBAT analysis showed XRCC1 gene genotypes and haplotypes were not significantly associated with nasopharyngeal carcinoma in our study population (rs1799782: chi(2) = 1.006, P = 0.605; rs25489: chi(2) = 0.470, P = 0.790; rs25487: chi(2) = 2.563, P = 0.278; haplotype: chi(2) = 3.004, P = 0.557, global statistic). For rs25487, the G allele (major allele) showed increased transmission under dominant model (Z = 1.985, P = 0.047). Whereas the C allele (minor allele) exhibited reduced transmission under recessive model (Z = -1.985, P = 0.047). However, no increased/reduced transmission was observed under additive model and with global statistic.</p><p><b>CONCLUSION</b>There is no evidence of an association between polymorphisms in XRCC1 gene and susceptibility of nasopharyngeal carcinoma in Cantonese nuclear families is observed in this study.</p>

Study on genetic polymorphisms of CYP2F1 gene in Guangdong population of China / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the genetic polymorphism of CYP2F1 gene, a member of CYP450 gene family in the healthy population and the patients with nasopharyngeal carcinoma (NPC) of Guangdong province, and furthermore analyze the relationship between CYP2F1 genetic polymorphism and the risk of developing NPC.</p><p><b>METHODS</b>By direct gene sequencing, all of 10 exons of CYP2F1 gene were detected in 40 peripheral blood specimens of patients with primary NPC. For the genetic polymorphism with high allelic frequency, mismatch PCR-RFLP technique was developed to identify the different frequency between 368 NPC cases and 344 cancer-free controls.</p><p><b>RESULTS</b>There were totally 35 SNPs identified in all of 10 exons and exon-intron junctions of CYP2F1 gene from 40 NPC patients, which included 10 missense mutations and 1 frame shift mutation. The most important mutation was C insertion located in 15-16 bp, which caused the frame shift. The allelic frequency of C insertion was 25%. However, there was no significant difference found between 368 NPC cases and 344 controls in allelic frequency of 15-16 bp C insertion mutation (P>0.05).</p><p><b>CONCLUSION</b>A lot of genetic polymorphism of CYP2F1 gene is found in Guangdong population of China. However, no single genetic polymorphism associated with the individual susceptibility to NPC can be identified. The cooperated operations with multiple genetic polymorphisms of one or more genes may be critical factors contributing to the development and progression of NPC.</p>

Prognostic significance of p21(WAF1) expression in osteosarcoma / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the expression of p21(WAF1) gene in human osteosarcoma and their relationships with clinicopathological parameters and prognostic value.</p><p><b>METHODS</b>The p21(WAF1) gene mRNA and p21 protein expression in 45 osteosarcoma and 10 fibrous dysplasia of bone specimens were analyzed by in situ hybridization and immunohistochemistry respectively.</p><p><b>RESULTS</b>(1) The positive rate of p21 protein expression in osteosarcoma was 17.7% (8/45). (2) The expression rate in high proliferation (4/10) significantly higher than that in low proliferation (4/35) osteosarcoma (chi2 = 4.34, P < 0.05). (3) The positive rate of p21(WAF1) mRNA expression in osteosarcoma was 42.2% (19/45). The expression rate in high proliferation (6/10) significantly higher than that in low proliferation (13/35) osteosarcoma (chi2 = 20.6, P < 0.01). (4) The survival time after operation of the patients with p21(WAF1) mRNA expression were higher than that of the patients with p21(WAF1) mRNA negative expression (P < 0.05).</p><p><b>CONCLUSIONS</b>(1) With the increase in degree of malignancy, the expression of p21(WAF1) mRNA and p21 protein in osteosarcoma tend decrease. (2) The expression of p21(WAF1) mRNA has a definite value in judging prognosis in osteosarcoma.</p>

NP9 gene inhibits tumorigenicity of nasopharyngeal carcinoma / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To study the effect of NP9 on the growth of transplanted nasopharyngeal carcinoma (NPC) in nude mice and explore the mechanisms involved.</p><p><b>METHODS</b>Recombinant pRc/CMV2-NP9 plasmid was constructed and transfected into the NPC cell lines by lipofectamine 2000. Cell clones stably expressing NP9 were obtained by detecting the mRNA expression of NP9 in G418-resistant clones with RT-PCR. The tumorigenicity and size of transplanted tumors were assessed after inoculation of NPC cells and their transgene clones into Balb/C mice. The expression of PCNA and cyclin D1 in transplanted tumors was detected by immunohistochemistry.</p><p><b>RESULTS</b>The expression of NP9 was detected in some of NP9 gene-transfected G418-resistant clones of CNE1 and SUNE1. In vivo experiments showed that the tumorigenicity of CNE19 clone was decreased significantly compared to that of CNE1 and its vector control, and the transplanted tumors grew more slowly from SUNE1/NP9 than from SUNE1 and SUNE1/vector. Compared with the vector control, the expression of cyclin D1 and PCNA in CNE1/NP9 transplants was decreased.</p><p><b>CONCLUSION</b>NP9 inhibits tumorigenicity and growth of NPC transplanted tumor by down-regulating the expression of cyclin D1 and PCNA.</p>

p21WAF1/CIP1 gene DNA sequencing and its expression in human osteosarcoma / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Mutation and expression change of p21WAF1/CIP1 may play a role in the growth of osteosarcoma. This study was to investigate the expression of the p21WAF1/CIP1 gene in human osteosarcoma, p21WAF1/CIP1 gene DNA sequence change and their relationships with the phenotype and clinical prognosis.</p><p><b>METHODS</b>p21WAF1/CIP1 gene in 10 normal people and the tumours of 45 osteosarcoma patients were examined using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) with silver staining. The PCR product with an abnormal strand was sequenced directly. The p21WAF1/CIP1 gene mRNA and P21 protein of 45 cases of osteosarcoma were investigated by using in situ hybridization and immunohistochemistry, respectively.</p><p><b>RESULTS</b>The occurrence of P21 protein in osteosarcoma was 17.78% (8/45), and p21WAF1/CIP1 mRNA expression in osteosarcoma was 42.22% (19/45). The p21WAF1/CIP1 gene DNA sequencing of amplified production showed that in p21WAF1/CIP1 gene exon 3 of 36 cases of human osteosarcoma, there were 17 cases (47.22%) with C-->T at position 609; 10 normal blood samples' DNA sequence analysis yielded 8 cases (80.00%) with C-->T at the same position.</p><p><b>CONCLUSIONS</b>Along with the increase of malignancy, the expression of p21WAF1/CIP1mRNA and P21 protein in osteosarcoma tends to decrease. It is uncommon for the p21WAF1/CIP1 gene mutation to occur in human osteosarcoma. As a result, the possible existence of tumour subtypes of p21WAF1/CIP1 gene mutation should be investigated. Our research leads to the location of p21WAF1/CIP1 gene polymorphism of Chinese osteosarcoma patients, which can provide a basis for further research.</p>