The effect of p53mut,P53wt and p16 on the expression of Smad4 in lung cancer H1299 cells / 临床外科杂志

Objective To investigate the influence of exogenous p53mut, p53wt and p16 on the expression of Smad4 in lung cancer H1299 cells. Methods Target genes (p53mut, p53wtand p16) were amplified by PCR and inserted into effective eukaryotic expression vector pIRES2-EGFP, respectively. These recombinant plasmids were transfected into H1299 cells by lipofectamine. The fluorescence microscope was employed to observe the transfected cells and the expression of EGFP. RT-PCR was used to validate the transfection efficiency. Western blot assay was used to detect the change of the Smad4 expression in H1299, Results Green fluorescence was observed under fluorescence microscope in the transfected H1299 cells at 72 hour post transfection. RT-PCR indicated that p53mut, p53wt and p16 genes were highly expressed in H1299 cell. There was no significant difference in Samd4 expression between the empty plasmid group and control group(P＞0.05). But the expression of Samd4 in p53mut transfected group was decreased(P＜0.05). On the contrary, the expression of Smad4 was increased in the p53wt transfected group and P53wt and p16 co-transfected group. Moreover, the increase was more obvious in the P53wt and p16 cotransfected group(P＜ 0.05). Conclusion P53mut gene transfection reduces the expression of Smad4 and P53wt. The co-infection of p53mut and p16 increases the expression of Smad4 in the H1299 cells. The tumor promoting effect of p53mut and the antitumor effect of p53

Clinical analysis of adult Philadelphia chromosome-positive acute lymphoblastic leukemia with p16 gene deletion / 中华血液学杂志

Objective@#To investigate the clinical implications of p16 gene deletion in adult Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) .@*Methods@#Retrospective analysis of clinical, immunophenotypic, cytogenetics, molecular characteristics and prognosis of 80 newly diagnosed Ph+ ALL patients with p16 deletion.@*Results@#Of 80 adult Ph+ ALL, the prevalence of p16 gene deletion was 31.3%. p16 gene deletion carriers frequently accompanied with high WBC counts (WBC≥30×109/L) and CD20 expression. The incidence of complex chromosome abnormality in p16 gene deletion group was higher than that in non-deletion group, with alternations in chromosome 7, 8, 19 and der (22) more frequently observed. There was no difference occurred between patients with or without p16 gene deletion in complete remission (CR) rate following induction chemotherapy combined with tyrosine kinase inhibitors (TKIs) . However, after three cycles of chemotherapy, the MMR and CMR rate in the p16 gene deletion group was lower than patients with wild-type p16 gene (P=0.034, P=0.036) . The p16 gene deletion patients showed no significant differences in MMR, CMR and relapse rate between Imatinib or Dasatinib plus chemotherapy (P>0.05) . Deletion of p16 gene was significantly associated with poor outcomes including worse overall survival (OS) (37.1% vs 54.1%, P=0.037) , lower disease free-survival (DFS) (12.4% vs 45.9%, P=0.026) , and increased cumulative incidence of relapse (P=0.033) . Among the 25 patients with p16 deletion, 14 underwent allo-HSCT and the median survival was 21 months, better than that of patients received chemotherapy alone (12 months) (P=0.030) .@*Conclusion@#This study indicated that deletion of p16 was associated with poor prognosis in adult Ph+ ALL, and the utility of second-generation TKI (Dasatinib) does not necessarily have an edge on efficacy over Imatinib, but allo-HSCT has the potential of elongating life expectancy. It is an important significance to define the status of p16 in Ph+ ALL for predicting prognosis and guiding therapy decision-making.

Effect of RNAi targetingBMI-1 gene on radiosensitivity of esophageal carcinoma cells / 中国癌症杂志

Background and purpose:B cell-specific MLV integration site 1 (BMI-1) gene plays an important role in DNA damage after exposure to irradiation. The present study aimed to investigate the effect ofBMI-1 on radio-sensitivity of esophageal carcinoma cell after down-regulation of BMI-1 expression by silencing siRNA.Methods:Three pairs of siRNA based on the sequences of the BMI-1 mRNA were synthesized (siRNA1, siRNA2 and siRNA3) by compa-ny, and transfected into cultured TE13 cells as the BMI-1 siRNA groups, and a negative one was synthesized to be used as the negative control (NC) group. The untransfected group was named as the control group. BMI-1 mRNA and protein expression in esophageal cancer TE13 cells were detected by reverse transcription polymerase chain reaction (RT-PCR) and Western blot in different groups. This study used flow cytometry assay to analyze cell cycle of transfected cells, and examined cellular growth and radiosensitivityin vitro by MTT and clone formation assay. mRNA and protein expression of p16 and CDK4 in esophageal cancer TE13 cells were detected by RT-PCR and Western blot.Results:The results of RT-PCR and Western blot showed that the expressions of BMI-1 at gene and protein levels were inhibited after silencing the BMI-1 gene. The mRNA and protein expression of BMI-1 in BMI-1 siRNA3 group were both significantly lower than that in BMI-1 siRNA1 and 2 groups. There was no significant difference in the cell proliferation among control, NC and BMI-1 siRNA3 groups. The values ofD0,Dq, and SF2 in BMI-1 siRNA3 group were 1.761, 2.122 and 0.6255, respectively, obvi-ously lower than those in control group (2.514, 2.694 and 0.8268) and those in NC group (2.506, 2.664 and 0.8231), while the value of N in BMI-1 siRNA3 group (3.336) was higher than that in control group (2.92) and that in NC group (2.895), which showed higher radiosensitivity in BMI-1 siRNA3 group. In addition, the cell cycle was arrested at G2/M phase after irradiation in control and NC groups. The percentage of G0/G1 phase in BMI-1 siRNA3 group was higher than that of control group and NC group, while the percentage of G2/M phase was lower than those in the latter. The up-regulation of p16 and down-regulation of CDK4 at gene and protein levels were detected after knockdown of BMI-1 expression by siRNA (P<0.01).Conclusion:siRNA could inhibitBMI-1 gene expression in esophageal cancer TE13 cells and enhance radiosensitivity, followed by eliminating the cell cycle arrest at G2/M stage after irradiationin vitro, which is related to the regulation of the protein expression ofp16 andCDK4.

The effects of fluoride on hypermethylation, transcription and expression of p16 gene in osteoblasts of rats / 中华地方病学杂志

Objective To establish an in vitro model of primnary osteoblasts fluorosis and to detect the influences of different doses of fluorosis on promoter methylation,transcription and expression of p16,then study the epigenetic effects of p16 gene on skeletal fluorosis.Methods Osteoblasts were isolated from Sprague-Dawley neonatal rats by enzyme digestion,and identified by morphology,alkaline phosphatasc staining and alizarin red staining.Osteoblast were treated with 0 (control group),200,400,800 and 1 600 μmol/L NaF for 72 h.The pl6 gene promoter region was amplified in the transcription initiation site-88-+ 143 region by bisulfatesequencing polymerase chain reaction (BSP).The mRNA transcription and the protein expression of p16 were detected by real-time quantitative PCR and Western blotting.Results Among the groups of osteohlasts treated with 200,400,800,1 600 μmol/L NaF,the positive rates of DNA methylation of promoter region in p16 gene of osteoblasts were 5.88％ (10/170),12.94％ (22/170),17.65％ (30/170) and 33.53％ (57/170),respectively.No DNA methylation was observed in the control group.There were significant differences between the control group and the NaF-treated osteoblasts groups (x2 =92.87,P ＜ 0.05).Average levels of p16 mRNA were 1.050 ± 0.073,0.869 ±0.037,1.065 ± 0.118 and 0.786 ± 0.148 in 200,400,800 and 1 600 μmol/L NaF-treated osteoblasts groups,compared with the control group (1.110 ± 0.315),there were significant differences among groups (all P ＜ 0.05) and 1 600 μmol/L NaF-treated osteoblasts group was much lower than other groups (P ＜ 0.05).Average levels of p16protein were 1.190 ± 0.050,1.214 ± 0.058,1.122 ± 0.123 and 0.320 ± 0.074 in 200,400,800 and 1 600 μmol/LNaF-treated osteoblasts groups,compared with the control group (1.115 ± 0.057),there were significant differences among groups (all P ＜ 0.05) and 1 600 μmol/L group was much lower than other groups.Conclusion NaF can cause hypermethylation in the promoter region of p16 gene,then suppress the expression of mRNA and protein,which might be one of the important mechanisms of cell proliferation change and cell cycle disorder in skeletal fluorosis.

A meta‑analysis of serum p16 gene promoter methylation for diagnosis of nonsmall cell lung cancer.

OBJECTIVES: To evaluate the diagnostic value of serum p16 gene promoter methylation for diagnosis of nonsmall cell lung cancer (NSCLC). MATERIALS AND METHODS: By searching the databases of PubMed and CNKI, we included all the published articles related serum p16 gene promoter methylation and nonsmall lung cancer. The true positive, false positive, false negative, and true negative data for each included publication were extracted by the reviewers. The diagnostic sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and area under the receiver operating characteristic (ROC) were pooled by MetaDiSc1.4 software. RESULTS: Finally, 13 manuscripts with 1440 subjects were involving in this diagnostic meta‑analysis. The pooled sensitivity and specificity were 0.25 (95% confidence interval [CI]: 0.18–0.32) and 0.95 (95% CI: 0.93–0.97), respectively, with randomized effect model. The pooled positive likelihood ratio and negative likelihood ratio were 5.08 (95% CI: 3.00–8.62) and 0.69 (95% CI: 0.62–0.77) with fixed effect model and randomized effect model, respectively. The diagnostic ROC curve for the included 13 publications was pooled by statistical software MetaDiSc14.0 according to the Bayes theorem. The pooled area under the ROC was 0.72 with its standard error of 0.10. CONCLUSION: According to the published articles, high specificity and low sensitivity were found in this meta‑analysis for the p16 gene promoter methylation in the diagnosis of NSCLC.

Correlation of HR-HPV infection and p16 gene expression in cervical cancer / 国际检验医学杂志

Objective To detect the expression of p16 and discuss the significance in genesis and development of cervical cancer. Methods FQ-PCR method was used to detect the expression levels of p16 mRNA in cervical cancer(CC),cervical intraepithelial neoplasia(CIN),and normal tissues.And in situ hybridization was used to detect HR-HPV in these tissues.Results The expres-sion levels of p16 were 0.79±0.34,0.70±0.36,0.26±0.21 in CC,CIN and normal cervical tissues,respectively.The difference was significant (P 0.05).The expression level of p16 in HR-HPV positive cases was significantly higher than that in HR-HPV negative cases (P <0.05).Conclusion p16 shows high expression level in cervical cancer,which is closely related to the infection of HR-HPV infection.It suggests that the high ex-pression of p16 play an important role in genesis and development of cervical cancer.

Effect of low dose radiation on expression of p16 gene in chronic myelogenous leukemia cells / 中华放射医学与防护杂志

Objective To investigate the effect of low dose radiation on the expression of p16 gene in chronic myelogenous leukemia.Methods Leukemic stem cells(LSCs)which expressed CD34+,CD38- and CD123+ were isolated from bone marrow cells obtained from twenty patients newly-diagnosedas chronic myeloid leukemia with EasySepTM magnet beads.Hematopoietie stem cells(HSCs) which expressed CD34+ and CD38- were isolated from human cord blood cells obtained from twenty full-term deliveries with EasySepTM magnet beads as control.HSCs vs LSCs samples were further divided into three dose groups,including 0,12.5 and 50 cGy,respectively.RT-PCR and real-time quantitative reverse transcription-polymerase chain reaction methods were used to detect mRNA expression of p16 gene in HSCs and LSCs after irradiation.Cells were harvested at different time for detection of cell cycle and apoptosis by flow cytometer.Results p16 mRNA level in CML-LSCs was increased slightly at 12.5 cGy,and significantly increased at 50 cGy(Z=-3.39,P<0.01),but ho significant change was found in HSCs.The percentage of CML-LSCs cell in G0/G1 stagewas increased 48 h after 12.5 cGy irradiation,and 72 h post-irradiation with 50 cGy.The apoptosis rate of CML-LSCs was gradually raised after LDR,especially at 72 h post-irradiation of 50 cGy[(17.75±11.76)%vs(6.13±4.71)%,Z=-2.37,P<0.01 ].Conclusions p16 gene transcription could be up-regulated by low dose radiation,which might provide a theoretical evidence for CML therapy and LDR in leukemic clinical application.

Methylation of p16 gene promoter in human pheochromocytomas and paragangliomas / 中华内分泌代谢杂志

Objective To elucidate gene mutation and promoter methylation changes of p16 gene in pheochromocytomas (PHEO) and paragangliomas (PGL) and to assess its relation with tumor clinical characters. Methods A total of 34 tumors (20 PHEO, 14 PG L, 15 benign, 19 malignant) were collected.Direct sequencing of p16 gene after PCR was performed to analyze genetic alterations. Hypermethylation of p16 gene promoter CpG island was analyzed by methylation specific PCR(MSP). In addition, mRNA expression was detected by RT-PCR. Results Homozygous deletion and gene mutation were not observed in 34 PHEO and PGL. Aberrant methylation of p16 gene promoter CpG island was found in 35.3% (12 of 34 tumors, 3 PHEO, 9 PGL). The p16 promoter hypermethylation in PGL was significantly higher than PHEO (P=0. 005). The higher p16 promoter hypermethylation was associated with malignant behavior, tumor number, and younger age at presentation, but no statistical significance, due to the limited number of cases. The p16 mRNA expression in malignant cases was lower than in benign tumors(0.83±0.65 vs 1.12±0.81 ,P=0.278). Conclusion p16 gene homozygous deletion and mutation were not frequent in PHEO and PGL. The promoter hypermethylation is mainly attributed to inactivation of the p16 gene.

O papel do gene p16 e do gene Dapk no controle do ciclo celular e na via carcinogênese vulvar / The role of p16 and Dark genes in cell cycle control and in the pathways of vulvar carcinogenesis

O câncer vulvar é o quarto tipo de câncer mais comum nas mulheres e representa 4,8% dos cânceres do trato genital inferior. O carcinoma de células escamosas é responsável por 80 a 90% de todos os cânceres de vulva. O carcinoma escamoso vulvar e suas lesões pré-malignas parecem desenvolver-se por dois caminhos distintos, baseados em características etiológicas e histopatológicas, tendo assim uma etiologia heterogênea. Um dos caminhos está relacionado com a infecção pelo HPV, e o outro, com as desordens epiteliais, tais como líquen escleroso e hiperplasia epitelial. O HPV é um importante fator causal das neoplasias do trato genital inferior. Ele está presente em cerca de 90% dos cânceres do colo uterino e 30 a 40% dos cânceres de vulva. O tipo mais prevalente é o 16, seguido pelos tipos 18, 45, 31 e 33. O estudo das alterações genéticas e epigenéticas, por meio da análise de metilação e imunoexpressão gênica, tem demonstrado uma grande versatilidade para o monitoramento molecular de pacientes com câncer, o que impulsiona pesquisas de métodos diagnósticos e terapêuticos do câncer. Nesta atualização pretendeu-se demonstrar as funções dos genes p16 e DAPK e as recentes pesquisas sobre a expressão destes genes nas vias da carcinogênse vulvar.

Vulvar cancer is the fourth commonest kind of cancer in women and it represents 4.8% of cancers in the lower genital tract squamous cell carcinoma is responsible for 80-90% of all vulvar cancers. Squamous cell carcinoma and it's premalignant lesions seem to develop in two distinct pathways, based on etiological and histopathological characteristics, thus forming a heterogeneous etiology. Whereas one of the pathways is related to HPV infection, the other is related to epithelial disorders such as: lichen sclerousus and epithelial hyperplasia. HPV is an important contributing factor of neoplasia in the lower genital tract. It is found in 90% of cervical cancers and in 30-40 % of vulvar cancers. The most prevalent kind is 16, followed by 18, 45, 31, and 33. The study of genetic and epigenetic alterations by means of methylation and genic immunoexpression has demonstrated great versatility to the monitoring ofpatients with cancer, which boosts researches of diagnostic and therapeutic methods for cancer. This update intends to demonstrate the role of p16 and DAPK genes as well as the recent researches regarding the expression of these genes in the pathways of vulvar carcinogenesis.

The relationship between the expression of P16 and the prognosis of oesophagus cancer / 中国基层医药

Objective Previons studies showed that,the gene of P16 is a kind of gene suppressing the cancer.its function once lose,the cell may change to cancer.Methods The expression of P16 has a closely relation with the malignant latent and evolve of the oesophagus cancer.ResulIs This research explored the relation between the P16 expression and the prognosis of oesophagus cancer,the results showed the positive rate of the expression of P16 is more low the rate ofexistence is more low,it in dicates the expression rate of P16 can reflect the prognosis of oesophagus cancer cell.Conclusion The expression of P16 missing or descending is closely rehted with the aggravate and evolve of oesophagus cancer,therefore the expression of P16 had a relation with the prognosis of oesophagus cancer.

The value of CT scan and tumor markers in sputum for early diagnosis of peripheral lung cancer / 重庆医科大学学报

Objective:To investigate the diagnostic value of telomerase activity and p16 gene methylation from exfoliated cells of sputum in 55 cases of solitary nodules and of being suspected of early peripheral lung cancer(T1N0M0).Methods:The sputum specimens from 34 cases of cancer nodes and 21 cases of benign lung lesion were detected for telomerase activity and p16 gene methylation by methylation analysis.Results:The qualitative diagnosis accuracy of CT scan was 61.8%(34/55) for peripheral lung cancer.Telomerase activity was positive in 29 cases:Sensitivity was 79.4%;Specificity was 90.5%;and accuracy was 83.6%.p16 gene methylation was in 11 cases:Sensitivity was 32.4%;specificity was 100%,and veracity was 58.2%.The sensitivity was increased to 86.1% by the combination of telomerase activity and p16 gene methylatiion.Conclusion:The results suggest that combining CT scan with telomerase activity and p16 gene methylation detection in sputum for patients with lung cancer may enhance the diagnostic value of conventional cytology.It is a promising approach to early diagnosis of lung cancer and massive screening in terms of its rapidity,economy and simplicity.

Detection and significance of promoter hypermethylation of p16 gene and MGMT gene in plasma from non-small cell lung cancer patients / 肿瘤

Objective: To detect the aberrant methylation in the promoter of p 16 and O6-methylguanine DNA methyltransferase (MGMT) gene in peripheral plasma from non-small cell lung cancer (NSCLC) patients and to evaluate the clinical significance in the screening and early diagnosis of NSCLC. Methods: A nested methylation-specific PCR (nMSP) was performed for the detection of promoter hypermethylation of p16 gene and MGMT gene in plasma from 65 NSCLC patients. Results: Of the 65 plasma samples, p16 gene promoter hypermethylation was detected in 19 patients (29.23%) and MGMT gene promoter hypermethylation was found in 16 patients (24.62%). However, promoter hypermethylation in p16 gene and MGMT gene was not found in plasma samples from the normal controls (P 0.05). Conclusion: Detection of the aberrant methylation in the promoter of p16 gene and MGMT gene in plasma from NSCLC patients by nMSP method might provide valuable information for the screening, early diagnosis, and prediction of prognosis of NSCLC.

Effects of N,N'-dinitrosopiperazine on cell proliferation in nasal and nasopharyngeal epithelia and expression levels of TRAF2 and p16 genes in transgenic mice / 中国耳鼻咽喉头颈外科

OBJECTIVE To investigate the effects of N,N'-Dinitrosopiperazine (DNP) on the cell proliferation of nasal and nasopharyngeal epithelia and the expression levels of TRAF2 and p16 genes in TgN (p53mt-LMP1)/HT transgenic mice and the relationships between them.METHODS The epithelial proliferating characteristics of nasal cavity and nasopharynx in TgN (p53mt-LMP1)/HT cancerous lesion inducing group treated by DNP (TI),TgN (p53mt-LMP1)/HT controlling group (TC), C57BL/6J cancerous lesion inducing group (CI) treated by DNP and C57BL/6J controlling group (CC) were observed for pathological evaluation by HE staining,and the expression levels of TRAF2 and p16 genes in these tissue samples were determined by immunohistochemical methods.RESULTS The occurring rates of precancerous lesions in nasal and/or nasopharyngeal epithelia in TI,TC,CI and CC groups were 90%,10%,0 and 0,respectively (P

The correlative analysis of indefinite dysplasia and dysplasia,and its p16 methylation in human gastric mucosa with Helicobacter pylori infection / 北京大学学报(医学版)

Objective:To compare the CpG island methylation status of p16 in subjects with gastric indefinite dysplasia or dysplasia,and investigate its association with exposure factors.Methods: Methylation status of p16 was determined by methylation specific PCR method and denaturing high-performance liquid chromatography analysis in 223 indefinite dysplasia and 130 dysplasia from Linqu County in Shandong Province,an area with high GC mortality rates.Multivariable analysis was used to analyze the relationship between p16 methylation and age,gender,cigarette smoking,alcohol drinking,and Helicobacter pylori infection.Results: The methylation frequency of p16 in indefinite dysplasia was not significantly different from that of dysplasia(28.3% vs.24.6%,P=0.46).No significant association was found between p16 methylation and age,gender,cigarette smoking,and alcohol drinking.In dysplasia,the association between p16 methylation and Helicobacter pylori infection was close to the statistical significance by univariate analysis that the relative risk of p16 methylation of the infected subjects(n=93) is higher than that of the uninfected subjects(n=37)(OR=2.62,95%CI: 0.92 to 7.43,P=0.07).But by multivariate analysis,there was no association between them(P=0.11).Conclusion: The frequency of p16 methylation in gastric mucosa of indefinite dysplasia was similar to that of dysplasia.p16 methylation status was not associated with age,but might be significantly associated with Helicobacter pylori infection.

Analysis of promoter hypermethylation of p16 gene in sera from primary liver cancer patients / 医学研究生学报

Objective:To analyze the aberrant methylation of p16 gene in sera from primary liver cancer patients and to evaluate the clinical significance. Methods:A methylation-specific PCR was performed for the detection of promoter hypermethylation of p16 gene in blood DNA from 64 cases of PLC patients,and to anamyze the relationship between the aberrant methylation of p16 gene and the clinical pathological data . Results:76.6%(49/64)of the sera from 64 cases of PLC patients showed hypermethylation for p16 promoter,whereas no methylated p16 gene promoter were found in sera from liver benign diseases patients and normal control. Methylated p16 gene promoter in sera did not strongly correlated with HBsAg, AFP,stage ,metastasis and differentiation in PLC. Conclusion:Detection of the aberrant methylation of p16 gene in blood DNA from PLC patients might offer an effective means for the earlier auxillary diagnosis of the malignancy.

Construction and identification of human p16 gene recombinant adenovirus / 第三军医大学学报

Objective To construct the recombinant adenovirus encoding human p16 gene for future gene therapy.Methods The human p16 gene fragment was cloned into the shuttle plasmid pAdTrack-CMV to form the transfer vector by the method of homogenous recombination in bacteria.Then the recombinant adenovirus was transfected into 293T cells using Lipofectine DOTAP.The target gene was detected by polymerase chain reaction(PCR).The titer and its infection rate were determined using the green fluorescent protein(GFP) expression in the shuttle plasmid.Results Restriction endonuclease and PCR analysis confirmed that the human p16 gene was successfully inserted into the adenovirus vector.The titer of the recombinant adenovirus was 6.1?10~(10)pfu/ml.The adenovirus has a strong effect on human fibroblast cells.Conclusion The recombinant adenovirus containing human p16 gene was successfully constructed by the method of homogenous recombination in bacteria.

Effect on radiosensitivity of human lung adenocarcinoma cells transfected with wild-type p16 gene / 中国癌症杂志

0.05); The result of FCM indicates that the cells transfected with p16 changed in cell cycle distribution ; proportion of G 2 M phase was increased, while that of S phase was decreased.Conclusions:Introduction of p16 gene into low expression human lung adenocarcinoma cell line Anip973 alters the radiation effect in a way which perhaps was correlated with the inhibition of sublethal damage repair and the cell cycle distribution change, but not in the high expression cell line AGZY83a.

DETECTION OF MTS1/p16 GENE EXPRESSION IN COLORECTAL CANCER BY RT-PCR / 解放军医学杂志

To investigate the deletion of MTS1/p16 gene in human colorectal carcinoma,the homozygous deletion of MTS1/p16 gene was checked by reverse transcriptase polymerase chain reaction from 60 patients with colorectal carcinoma.The specimens consisted of 35 colorectal carcinoma,15 tumor-adjacent tissues and 10 normal colorectal mucosa. It was found that 17 14% (6/35) colorectal carcinoma specimens showed homozygous deletion of MTS1/p16 gene.No deletion was detected in tumor-adjacent tissue and normal colorectal mucosa.Deletion of MTS/p16 gene may play a role in the progression of colorectal carcinoma.

Study on Deletion and Mutation of p16 Gene in Primary Pancreatic Carcinoma / 中国医师杂志

Objective To examine deletion and mutation of p16 gene in primary pancreatic carcinoma to evaluate the relationsip between p16 gene alteration and carcinogenesis of pancreatic carcinoma as well as its progression. Methods Deletion and mutation of p16 gene in 28 primary pancreatic carcinomas and 28 normal tissues adjacent to tumors were detected by PCR-based deletion analysis technique and PCR-SSCP respectively, and the relationship between the results of detection and the clinical parameters was analysed. Results In 28 pancreatic carcinomas, homozygous deletion and mutation of p16 gene were found in 4 and 5 cases respectively. The frequency of p16 gene alteration was 32 1%. p16 gene alteration closely correlated with lymph node metastasis (P

p16 gene methylation status of and its effect on mRNA expression in hepatocellular carcinoma / 中国癌症杂志

Purpose:To investigate the status of p16 gene and its influence in p16 mRNA expression in primary hepatocellular carcinoma (HCC). Methods:The methylation status of p16 gene and expression of p16 mRNA were examined by methylation-specific PCR (MSP) and RT-PCR in twenty-five primary HCC and corresponding paracancerous tissue specimens.Results:Methylation was detected in 12 of 25 (52.0%) tumor tissue specinmens, while 6 of 25 (24.0%) in corresponding paracancerous tissue specimens. Loss of p16 mRNA expression was found in 19 specimens with methylated p16 gene,while expression of p16 mRNA was detected in 27 of 31 specimens with unmethylated p16 gene. There was significant difference in mRNA expression between specimens with methylated p16 and unmethylated p16.Conclusions:p16 gene methylation is a frequent event in HCC. The methylation of p16 gene might lead to loss of p16 mRNA expression. Detection of p16 gene methylation may be a useful marker in the molecular diagnosis of hepatocellular carcinomas.