FREQUENT DELETION OF MTS1/p16 GENE AND CORRELATION WITH CLINICOPATHOLOGICAL PARAMETERS IN ENDOMETRIAL CARCINOMA

Objective: To investigate the possible relationship between deletion of MTS/p16 gene and progression of endometrial carcinoma Methods: Forty six primary endometrial carcinoma, 7 tumor adjacent endometrial tissue, 10 normal endometrial tissue specimen and 5 xenografts from patients with endometrial carcinoma were examined for homozygous deletion of MTS/p16 gene by polymerase chain reaction based analysis Results: Of 46 endometrial cancer specimens, 9 showed homozygous deletion, no deletion was detected in the tumor adjacent and normal endometial tissues Nor was it detected in well differentiated endometrial carcinoma and all xenografts Conclusions: Deletion of MTS1/p16 gene might contribute to the progression of endometrial carcinoma and could be served as indicator for predicting prognosis

STUDY OF DELETION OF P16 GENE IN THE PROGRESSION OF BRAIN ASTROCYTOMAS

Objective: To study the relationship between deletion of P16 gene and occurrence and progression of astrocytomas Methods: The techniques of polymerase chain reaction (PCR) and immunohistochemistry were used to detect the deletion of exon2 of P16 gene and expression of P16 gene in 52 cases of Brain astrocytoma Results: The deletion rate of exon2 of P16 gene in the tumors analyzed was 34 6% Most of them with deletion of exon2 of p16 gene were high grade astrocytomas (grade III 42%, grade IV 50%) 61 5% of the tumors were absent from expression of p16 and the deletion rate of p16 protein increased with the grade of astrocytoma (X 2=10 83, P <0 005) Conclusion: Deletion of p16 gene and protein may correlate with the malignant progression of astrocytoma

温石棉对内皮细胞Wnt5a、p16和p21表达的影响

目的探讨温石棉对人脐静脉内皮细胞(HUVECs)的影响。方法实验组以50、100、200 mg/L温石棉纤维液刺激HUVECs 24、48、72 h,对照组仅加RPMI 1640培养基培养细胞,观察细胞形态变化,β-半乳糖苷酶法分析细胞衰老情况,四甲基偶氮唑蓝法检测细胞存活率。采用实时荧光定量PCR法检测细胞中Wnt5a、p16和p21 mRNA的表达情况。结果实验组HUVECs多呈梭形,部分呈圆形或不规则形,出现裸核及空泡现象,可见死亡细胞。随温石棉质量浓度及暴露时间的增加,细胞活性逐渐降低,衰老细胞逐渐增多。100 mg/L温石棉处理HUVECs 24 h时,细胞生长较活跃。与对照组相比,实验组Wnt5a、p16和p21 mRNA表达水平均增高(P<0.05)。结论温石棉可促进HUVECs衰老,Wnt5a、p16和p21参与此过程。

基于p16/ki67细胞学双染检测宫颈癌前病变的研究

目的探讨p16/ki67细胞学双染检测在宫颈病变筛查中的应用价值。方法收集妇科宫颈病变门诊患者56例为研究对象,所有患者均行宫颈液基细胞学检查(TCT)、人乳头瘤状病毒(HPV)检测、阴道镜活检,并进行p16/ki67双染,分析比较双染与TCT、HPV检查诊断宫颈病变的效能,并研究p16/ki67双染诊断宫颈病变的价值。结果在细胞学为非侵入式负荷监测(NILM)、不典型鳞状细胞(ASC-US)、低级别鳞状上皮内病变(LSIL)以上病变的分级患者中p16/ki67双染阳性的比例分别是15.38%、66.67%、92%,不同宫颈组织学诊断结果中慢性宫颈炎、宫颈上皮内瘤变Ⅰ级(CINⅠ)、宫颈上皮内瘤变Ⅱ级(CINⅡ)和Ⅲ级(CINⅢ)的患者中p16/ki67双染阳性率分别为6.66%、75%、78.57%、100%,总体差异有统计学意义(P<0.05)。结论p16/ki67免疫细胞化学染色阳性率与宫颈癌前期病变的严重程度呈现正相关。P16/ki67双染较TCT和HPV提高了宫颈病变筛查的灵敏性和特异性,并提高了高级别鳞状上皮内病变(HSIL)的检出率,减少阴道镜的转诊率,值得应用于临床。

P53、P16及Ki-67与早期食管癌患者ESD术后复发的关系分析

目的 分析研究抑制蛋白基因P53(P53)、抑制蛋白基因P16(P16)及细胞增殖核抗原Ki-67(Ki-67)与早期食管癌患者内镜黏膜下剥离术(ESD)术后复发的关系。方法 选取2019年1月至2023年1月三门峡市中心医院收治80例的早期食管癌患者作为研究对象,均进行ESD治疗。比较所有患者癌组织与癌旁组织(距肿瘤边缘>3 cm,镜下未见肿瘤组织或不典型增生组织)P53、P16、Ki-67蛋白表达。ESD术后对患者随访1年,根据有无术后复发食管癌,将患者分为复发组(n=20)与无复发组(n=60)。比较两组癌组织P53、P16、Ki-67蛋白表达。采用多因素Logistic回归分析早期食管癌患者ESD术后复发的影响因素,并绘制ROC曲线分析P53、P16、Ki-67蛋白表达与早期食管癌患者ESD术后复发。结果 与癌旁组织相比,癌组织P53、Ki-67蛋白表达升高,P16蛋白表达降低(t=9.276、13.987、10.595,均P<0.05);复发组的癌组织P53、Ki-67蛋白表达均高于无复发组,P16蛋白表达低于无复发组(t=5.086、4.648、5.139,均P<0.05);多因素Logistic回归分析显示,肿瘤低分化(OR=1.870)、肿瘤浸润侵犯黏膜下层(OR=1.808)、有淋巴结转移(OR=2.089)、P53蛋白高表达(OR=2.046)、P16蛋白低表达(OR=1.988)及Ki-67蛋白高表达(OR=1.761)均是早期食管癌患者ESD术后复发的独立危险因素(P<0.05);ROC曲线分析显示,P53、P16、Ki-67蛋白表达及联合检测的曲线下面积(AUC)分别为0.803、0.828、0.834、0.942,联合检测优于单一检测(P<0.05)。结论 P53、P16及Ki-67蛋白与早期食管癌患者ESD术后复发情况相关,可以作为辅助预测的相关诊断指标。

DELETIONS AND POINT MUTATIONS OF p16,p15 GENE IN PRIMARY TUMORS AND TUMOR CELL LINES

Aberrations of chromosome 9 p21 22 are involved in the genesis of many forms of cancer.The gene p16 and p15 have been assigned to this region.Both p16 and p15 are an inhibitor of cyclin D cdk4,cyclin D cdk6 complex and have been implicated in a wide variety of cancer types,including the germline of patients with familial melanoma.In order to investigate and compare the status of p16,p15 gene in primary tumors and cell lines,we examined 357 primary tumors and 29 cell lines derived from diverse tumor types.In addition to analysis of these primary tumors and cell lines,blood specimens from 91 patients either with sporadic multiple cancers or from cancer prone families were also analyzed.The data showed the following:1)Homozygous deletions of p16,p15 were comparatively rare and far less common than previously reported,although hemizygous deletions were observed in a significant fraction of many tumor types;2)the incidence of p16,p15 deletions(either homozygous deletions or heterozygous deletions)varied significantly among different tumor types;3)most deletions involved in both p16 and p15 genes;4)sequence variations in the coding sequence of p16,p15 were comparatively rare among these tumor types,though mutations and polymorphisms were identified;5)some tumors which showed LOH at 9p,containing p16 and p15 gene,did not show deletions or point mutations in the p16,p15 gene.6)In a subset of retinoblastoma and osteosarcoma where no Rb gene mutations were present a significant fraction was found to contain p16,p15 gene deletions.

INACTIVATION OF P16 GENE IN LEUKEMIA

To determine the frequency of p16 gene inactivation in leukemia cells, and to evaluate their value in the prediction of their clinical outcome. Bone marrow or peripheral blood samples from 48 patients with leukemia were examined by multiplex polymerase chain reaction(MPCR) to detect p16 gene homozygous deletion, and restriction enzyme PCR to detect p16 gene methylation. p16 gene inactivation were detected in 10 of the 48 patients(20.4%). They were five patients with p16 homozygous deletion, and five patients with p16 methylation, respectively. p16 gene inactivation correlates with adverse prognosis features. The patients with p16 inactivation had poor response to chemotherapy, and had significantly shorter survival times than the patients in whom p16 gene was preserved(P<0.001). The inactivation of p16 gene play a key role in the pathogenesis and the progression of some leukemia. The detection of p16 gene is reliable prognostic factor that predict shortened survival times.

Molecular and immunohistochemical study of the inactivation of the p16 gene in primary hepatocellular carcinoma

Obejctive To determine whether p16 gene is involved in the genesis of primary hepatocellular carcinoma (HCC) Methods Twenty five HCC tumor samples with corresponding non tumor liver tissue specimens were examined for p16 gene alterations The identification of deletion of exon 1 and exon 2 in p16 gene was performed using comparative multiplex polymerase chain reaction (PCR) analysis The point mutation of exon 2 in p16 gene was investigated by single strand conformational polymorphism (SSCP) analysis, and the status of p16 gene methylation was screened using a PCR based methylation analysis 35 parafin embedded specimens of HCC with corresponding non tumor liver tissues, including the 25 cases described above for screening p16 gene alterations, were investigated for p16 protein expression using immunohistochemical analysis Results Among 25 cases, 2 homozygous deletions and 1 hemizygous deletion were found in HCC samples No point mutation was identified in the remaining 22 tumor samples without p16 gene deletions Hypermethylation was detected in 24% (6/25) of tumor samples However, the corresponding non tumor liver tissue specimens were always unmethylated at the p16 locus Loss of p16 protein expression occurred in 16 of 35 (45 7%) tumor samples, and all the non tumor liver tissue specimens showed positive p16 staining For the 25 cases examined for p16 gene alterations, the loss of p16 protein expression was observed in all tumors with p16 gene alterations and also in 3 tumors without p16 gene alterations Conclusion Inactivation of the p16 gene may play an important role in the genesis of primary hepatocellular carcinoma

Expression of p16 gene and Rb protein in gastric carcinoma and their clinicopathological significance

AIM:To analyze the correlation between the protein expression of p16 and Rb genes in gastric carcinoma (GC), to investigate the role of p16 gene in invasion and lymph node metastasis of GC, and to examine the deletion and mutation in exon 2 of p16 gene in GC. METHODS: The protein expression of p16 and Rb genes was examined by streptavidin-peroxidase conjugated method (S-P) in normal gastric mucosa, dysplastic gastric mucosa and GC. The deletion and mutation of p16 gene were examined by polymerase chain reaction (PCR) and polymerase chain reaction single strand conformation polymorphism (PCR-SSCP) respectively in normal gastric mucosa and GC. RESULTS: The positive rates of P16 and Rb protein expression respectively were 96% (77/80) and 99% (79/80) in normal gastric mucosa, 92% (45/50) and 80% (40/50) in dysplastic gastric mucosa, 48% (58/122) and 60% (73/122) in GC. The positive rates of P16 and Rb protein expression in GC were significantly lower than that in normal gastric mucosa and dysplastic gastric mucosa (P<0.05). The positive rate of P16 protein expression in mucoid carcinoma (10%, 1/10) was significantly lower than that in poorly differentiated carcinoma (51%, 21/41), undifferentiated carcinoma (58%, 15/26) and signet ring cell carcinoma (62%, 10/16) (P<0.05). The positive rates of P16 protein in 30 cases of paired primary and lymph node metastatic GC were 47% (14/30) and 17% (5/30) respectively, being significantly lower in the later than in the former (P<0.05). There was no mutation in exon 2 of p16 gene in the 25 freshly resected primary GCs. But five cases in the 25 freshly resected primary GCs displayed deletion in exon 2 of p16 gene. The positive rate of both P16 and Rb proteins was 16% (14/90), and the negative rate of both P16 and Rb proteins was 8% (7/90) in 90 GCs. The rate of positive P16 protein with negative Rb protein was 33% (30/90). The rate of negative P16 protein with positive Rb protein was 43% (39/90). There was reverse correlation between P16 and Rb expression in 90 GCs CONCLUSION: The loss protein expression of p16 and Rb genes is related to GC. The loss expression of P16 protein is related to the histopathologic subtypes and lymph node metastasis of GC. Expression of P16 and Rb proteins in GC is reversely correlated. The deletion but not mutation in exon 2 of p16 gene may be involved in GC.

Effect of 5-Aza-2'-deoxycytidine on the P16 tumor suppressor gene in hepatocellular carcinoma cell line HepG2

INTRODUCTIONHepatocellular carcinoma (HCC) is one of the mostcommon human malignancies worldwide[1,2], and isclosely associated with infection of HBV and HCVand contamination of aflatoxin B1[3-6]. Althoughthe molecular mechanisms of hepatocarcinogenesisremain poorly understood, an increasing number ofgenetic abnormalities have been recognized[7-10],for example, the p16 gene[11,12] the p53gene[13-18], the E-cadherin gene[19], and the c-mycgene[20].

p16 gene methylation in colorectal cancers associated with Duke's staging

AIM: To explore the association of methylation of the CpG island in the promotor of the p16 tumor suppressor gene with the clinicopathological characteristics of the colorectal cancers. METHODS: Methylation-specific PCR (MSP) was used to detect p16 methylation of 62 sporadic colorectal cancer specimens. RESULTS: p16 methylation was detected in 42% of the tumors.Dukes'staging was associated with p16 methylation status.p16 methylation occurred more frequently in Dukes'C and D patients (75.9%) than in Dukes'A and B patients (12.1%). CONCLUSION: p16 methylation plays a role in the carcinogenesis of a subset of colorectal cancer, and it might be linked to poor prognosis.

Alterations of FHIT Gene and P16 Gene in Nickel Transformed Human Bronchial Epithelial Cells

Objective To study the alterations of FHIT gene and P16 gene in malignant transformed human bronchial epithelial cells induced by crystalline nickel sulfide using an immortal human bronchial epithelial cell line, and to explore the molecular mechanism of nickel carcinogenesis. Methods 16HBE cells were treated 6 times with different concentrations of NiS in vitro, and the degree of malignant transformation was determined by assaying the anchorage-independent growth and tumorigenicity. Malignant transformed cells and tumorigenic cells were examined for alterations of FHIT gene and P16 gene using RT-PCR, DNA sequencing, silver staining PCR-SSCP and Western blotting. Results NiS-treated cells exhibited overlapping growth. Compared wkh that of negative control cells, soft agar colony formation efficiency of NiS-treated cells showed significant increases （P〈0.01） and dose-dependent effects. NiS-treated cells could form tumors in nude mice, and a squamous cell carcinoma was confirmed by histopathological examination. No mutation of exon 2 and exons 2-3, no abnormal expression in pl6 gene and mutation of FHIT exons 5-8 and exons 1-4 or exons 5-9 were observed in transformed cells and tumorigenic cells. However, aberrant transcripts or loss of expression of the FHIT gene and Fhit protein was observed in transformed cells and tumorigenic cells. One of the aberrant transcripts in the FHIT gene was confirmed to have a deletion of exon 6, exon 7, exon 8, and an insertion of a 36 bp sequence replacing exon 6-8. Conclusions The FHIT gene rather than the P16 gene, plays a definite role in nickel carcinogenesis. Alterations of the FHIT gene induced by crystalline NiS may be a molecular event associated with carcinogen, chromosome fragile site instability and cell malignant transformation. FHIT may be an important target gene activated by nickel and other exotic carcinogens.

IDH突变型低级别星形细胞瘤p16蛋白表达与CDKN2A基因缺失状况的相关性

目的:以异柠檬酸脱氢酶(isocitrate dehydrogenase,IDH)突变型星形细胞瘤为研究对象,探讨利用p16蛋白免疫标记替代CDKN2A基因纯合性缺失检测的可行性。方法:收集我院既往组织学诊断为低级别星形细胞瘤(WHO 2级)且伴有IDH突变的胶质瘤42例,通过免疫组化方法检测肿瘤组织中p16蛋白表达,分别依据其胞核或胞浆阳性表达率将肿瘤分为阴性(阳性率0%)、低表达(0%<阳性率≤10%)、中表达(10%<阳性率≤25%)、高表达(25%<阳性率≤50%)及过表达(阳性率>50%)5个组别;利用FISH方法检测肿瘤CDKN2A基因纯合性缺失与杂合性缺失状况;采用Fisher精确检验评价p16蛋白表达水平与CDKN2A基因缺失间的相关性。结果:胞核p16蛋白表达水平与CDKN2A基因纯合性缺失间存在显著相关(P<0.001)。阴性组(4/4,100%)均检测到CDKN2A纯合性缺失,中、高及过表达组(22/22,100%)均未检测到CDKN2A纯合性缺失。低表达组与CDKN2A纯合性缺失间缺乏明确对应关系,其中3例(3/16,18.75%)检出纯合性缺失,13例(13/16,81.25%)未检出纯合性缺失。胞核p16蛋白表达水平与CDKN2A杂合性缺失无相关(P=0.228)。胞质p16蛋白表达水平与CDKN2A纯合性(P=0.086)或杂合性(P=0.884)缺失均无相关。结论:IDH突变且组织学呈低级别的星形细胞瘤中,胞核p16蛋白阴性(阳性率0%)或中等及以上表达(阳性率>10%)分别提示存在或不存在CDKN2A纯合性缺失。在上述区间p16蛋白与CDKN2A纯合性缺失间存在良好匹配关系,可用于协助病理诊断与分级。胞核p16蛋白低表达(0%<表达率≤10%)则不能预测CDKN2A纯合性缺失状态,此时仍需进行CDKN2A基因层面检测。

The effects of CYP1A1 gene polymorphism and p16 gene methylation on the risk of lung cancer in a Chinese population

Objective： To investigate the relationship between the genetic polymorphism of CYP1A1 and the genetic susceptibility to lung cancer as well as to study the effects of the methyiation in p16 gene on the risk of lung cancer in a Chinese population. Methods： A case control study was conducted among 47 cases of lung cancer and 94 controls. The genetic polymorphism of CYP1A1 was tested with method of PCR-RFLP, and a methylation-specific PCR （MSP） was performed to detect p16 methylation. Results： It showed that there was no significant difference in frequencies of the genotypes of CYP1A1 between the two groups （P 〉 0.05）. Synergistic effects were not found between smoking and CYP1AI. Methylated p16 gene was found in 44.7% （21/47） of lung cancer tissues and in 17.0% （8/47） of normal lung tissues with significant difference （P 〈 0.05）. Conclusion： The genetic polymorphism of CYP1A1 does not increase the risk of lung cancer in a Chinese population. The methylation in p16 gene may be the most common mechanism to inactivate p16 gene in lung cancer, and is not significantly associated with genotype of CYP1A1,

PROMOTER HYPERMETHYLATION OF p16 GENE AND DAPK GENE IN SERA FROM HEPATOCELLULAR CARCINOMA (HCC) PATIENTS

Objective： To analyze the aberrant methylation of p16 gene and DAPK gene in sera from primary liver cancer patients ad to evaluate the clinical significance. Methods： A methylation-specific PCR was performed for the detection of promoter hypermethylation of p16 gene and DAPK gene in blood DNA from 64 cases of HCC patients, and to analyze the relation of the aberrant methylation of p16 gene and KAPK gene and the clinical pathological data. Results： 76.6%（49/64） of the sera from 64 cases of HCC patients showed hypermethylation for p16 promoter and 40.6% （26/64） for KAPK promoter, whereas no methylated p16 gene promoter and DAPK gene promoter were found in sera from benign liver diseases patients and normal control. Methylated p16 gene and KAPK gene promoters in sera did not strongly correlated with HBsAg, stage, metastasis and differentiation in HCC; but strongly correlated with AFP. Conclusion： Detection of the aberrant methylation of p16 gene and KAPK gene in blood DNA from HCC patients might offer an effective means for the earlier auxiliary diagnosis of the malignancy.

Effects of Exogenous p16^(ink4a) Gene on Biological Behaviors of Human Lung Cancer Cells

The effects of exogenous p16^ink4a gene on biological behaviors of human lung cancer cell line with homozygous deletion of p16^ink4a gene were investigated. Exogenous p16^ink4a gene was transfected by lipofectin into human lung cell line A549, in which p16^ink4a gene was homozygously deleted. The expression of p16^ink4a mRNA and protein was detected by RT-PCR and immunocytochemistry, respectively. The changes in the behaviors of the transfected cell lines in vitro and in vivo were observed. In the transfected cell line A549, the exogenous p16^ink4a gene could be stably expressed. The growth of A549 cells transfected with p16^ink4a gene was obviously slowed down. Flow cytometry revealed that transfection of the exogenous p16^ink4a gene resulted in A549 cell lines arrest in G1 phase of cell cycle. The tumorigenicity of these transfected cells in nude mice could be inhibited, and the tumor growth of nude mice was significantly suppressed. It was concluded that exogenous p16^ink4a gene may be stably expressed in human lung cancer cell line A549. The expression of the introduced p16^ink4a could block lung cancer cells to entry into S phase of cell cycle and inhibit tumor malignant growth both in vitro and in vivo.

Quantitative Study on Expression of P16 Multiple Tumor Suppressor Gene in Salivary Gland Neoplasm

The expression of P16 gene were found in all 3 groups. The positive unit (PU) was higher in tumor group and cancer group than that in normal group ( P <0.01). Furthermore, the PU of P16 was stronger in cytoplasm than in nucleus. Malignant tumors and acini surrounding the tumor revealed strong positives and week positives respectively. The PU of P16 gene was higher in deep lobe of recurrent parotid neoplasm with incomplete capsule than that in shallow lobe of primary parotid neoplasm with complete capsule. Our findings suggests that P16 gene plays equally important role in the salivary gland tumors and tumors in other part of the body.

Tumor suppressor gene p16 and Rb expression in gastric cardia precancerouslesions from subjects at a high incidence area in northern China

AIM:To further understand the molecular basis for gastric cardia carcinogenesis and to provide etiological clues. METHODS: Endoscopic mucosa biopsy and histopathological examinations were made on 37 subjects from a high incidence area for both esophageal and gastric cardia carcinomas in northern China. All the biopsy samples were fixed in 850 ml. (-1)L alcohol and embedded in paraffin. Each block contained one piece of tissue and was serially section at 5 microm. Immunohistochemistry (ABC) was carried out on these gastric cardia samples to determine the alterations of p16 and Rb. RESULTS: Based on the histopathlogical examination there were 11 cases of chronic superficial gastritis, 12 cases of chronic atrophic gastritis and 14 cases of dysplasia. The immunostaining demonstrated different levels of unclear immunostaining of p16 and Rb in normal gastric cardia tissue and the tissues with different severity of lesions. With the lesions progressing, the positive immunostaining rates for p16 protein had a decreasing tendency. In contrast, the positive immunostaining rate for Rb protein had an increasing tendency. There was a significant negative relationship between the two parameters. Changes of p16 was CSG 11(100%), CAG 7(58%), DYS 4(29%) and changes of Rb was CSG 2(18%), CAG 8(67%) and DYS 12(86%), (P【0.05). CONCLUSION: The alterations of p16 and Rb protein may play a role in the early stages of gastric cardia carcinogenesis.

PROMOTER HYPERMETHYLATION OF p16 GENE IN PRE- AND POST-OPERATIVE PLASMA OF PATIENTS WITH GASTRIC ADENOCARCINOMA

Objective: To detect promoter hypermethylation of p16 gene in matched pre- and post-operative plasma of patients with gastric adenocarcinoma for evaluating the effectiveness of therapeutic intervention. Methods: Tissue samples, pre- and post-operative plasma of 84 patients were collected. Plasma of 15 healthy people was collected as control. After sodium-bisulfite treatment, extracted DNA was amplified for p16 promoter by methylation-specific polymerase chain reaction (MSP). The PCR products were detected by both gel-ethidium bromide electrophoresis and high performance liquid chromatogram (HPLC). Results: Among 84 patients, p16 hypermethylation was detected in 26 (31.0%) cancer tissues and 2 (0.02%) tumor-adjacent tissues and 12 (14.3%) pre-operative plasma, while negative in plasma of healthy people. For positive plasma cases, the paired tumor tissues were confirmed to be methylated. Within available 30 pairs of matched pre- and post-operative plasma, 6 pre-operative plasma was positive, and only 1 of 6 plasma remained hypermethylated after surgery. The results detected by HPLC exactly matched those by gel-electrophoresis. Conclusion: The alteration of status of p16 hypermethylation in post-operative plasma is considered the consequences of surgical intervention. Although p16 hypermethylation has no role in pre-operative staging of gastric cancer, detecting hypermethylated p16 in plasma could be utilized in monitoring patients after surgery.