HCV肝炎肝硬化中核心蛋白、p14ARF和p21WAF1的表达

目的检测HCV肝炎、肝硬化组织中的核心蛋白、p14ARF、p21WAF1的表达及其相关性,探讨HCV核心蛋白对p14ARF、p21WAF1的表达作用.方法收集HCV表达阳性的肝炎、肝硬化组织23例,采用免疫组织化学EnVision两步法检测HCV感染的肝炎、肝硬化组织的核心蛋白、p14ARF、p21WAF1的表达,并分析三者间的关系.结果核心蛋白、p14ARF、p21WAF1的阳性表达主要定位于细胞核. 在核心蛋白均阳性的组织中,p14ARF的阳性表达率为69.6%,p21WAF1表达率为13%;三组间的阳性强度比较,差异有显著性(P=0.01),HCV核心蛋白与p14ARF、p21WAF1各组间的P值均<0.01;HCV核心蛋白与p14ARF、p21WAF1阳性强度两者间相关性检验,相关系数rs分别为-0.053、0.45(P值分别为0.72、0.20),表明无相关性.结论 HCV核心蛋白对p14ARF、p21WAF1的表达有影响可能间接促进p14ARF的表达,但抑制p21WAF1的表达.     

人脑神经胶质瘤中p16、p21~(WAF1/CIP1)蛋白表达的研究

目的　探讨 p16、p2 1WAF1/CIP1两种抑癌基因与人脑神经胶质瘤恶性程度的关系。方法　采用SABC免疫组织化学方法对 6 4例人脑胶质瘤组织及 8例正常脑组织标本中p16和 p2 1WAF1/CIP1表达情况进行检测 ,并进行相关分析。结果　①p16和 p2 1WAF1/CIP1阳性表达率在人脑胶质瘤中分别为 4 5 .3%和 6 4 .1%与正常脑组织中的表达情况差异显著 (P <0 0 5 ) ;②p16蛋白和 p2 1WAF1/CIP1蛋白阳性表达率均随着胶质瘤的恶性程度的增高而降低 ,差异显著 (P <0 0 1) ,且呈负相关关系 ;③p16蛋白和 p2 1WAF1/CIP1蛋白可协同表达 ,且在正常脑组织和脑胶质瘤各分级中 p16蛋白和 p2 1WAF1/CIP1蛋白协同表达率差异显著 (P <0 0 5 ) ,并呈负相关关系。结论　p16与p2 1WAF1/CIP1蛋白的阳性表达率及协同表达率可在一定程度上反映胶质瘤细胞的恶性程度 ,可作为判断其恶性程度的有效指标     

胃癌组织cyclinE和p21^WAF1／CIP1蛋白表达的意义

目的探讨cyclinE和p21WAF1/CIP1蛋白在胃癌发生发展中的作用及其表达的意义.方法采用免疫组化S-P法检测正常胃黏膜、萎缩性胃炎伴肠上皮化生、萎缩性胃炎伴不典型增生各20例和78例胃腺癌组织中cyclinE和p21WAF1/CIP1蛋白表达.结果cyclinE蛋白阳性表达在胃癌组高于正常胃黏膜、萎缩性胃炎伴肠上皮化生组,而p21WAF1/CIP1蛋白表达则相反,差异均有显著性(P<0.05);cyclinE、p21WAF1/CIP1蛋白表达与胃癌细胞分化程度相关(P<0.05);有肝转移的胃癌组cyclinE阳性表达率高于无肝转移组(P<0.05);有淋巴结转移组p21WAF1/CIP1蛋白表达率低于无淋巴结转移组(P<0.05).结论cyclinE蛋白高表达与p21WAF1/CIP1蛋白失表达可能参与胃癌的发生发展过程,检测cyclinE和p21WAF1/CIP1蛋白作为反映胃癌病理学特点的参考指标可能有一定意义.     

骨肉瘤中p53、p21WAF1、cyclinA蛋白的表达及其意义

目的探讨骨肉瘤中p53、p21WAF1、cyclinA蛋白的表达及相互关系.方法应用免疫组化方法对骨肉瘤组织及正常软组织中p53、p21WAF1、cyclinA的蛋白表达进行检测.结果正常软组织中p53表达均阴性,28%(14/50)骨肉瘤中可检测到p53蛋白的异常积累;正常软组织中均有不同程度的p21WAF1蛋白的阳性表达,52%(26/50)骨肉瘤p21WAF1阴性,骨肉瘤中p21WAF1的蛋白表达表现为p53蛋白依赖性的方式;正常组织中cyclinA为阴性,75.6%(28/37)骨肉瘤中存在cyclinA蛋白过表达,cyclinA与p21WAF1的表达呈负相关(r=-0.874,P＜0.01);p21WAF1蛋白的表达与骨肉瘤的分化呈正相关(r=0.687,P＜0.01).结论p53蛋白的异常积聚、p21WAA1的失表达及cyclinA的过表达参与了骨肉瘤失控的增生及肿瘤的形成.     

膀胱移行细胞癌细胞周期调节相关基因表达与肿瘤生物学行为的关系

目的：探讨细胞周期调节相关基因p16INK4,p21WAF／CIP1,p53mlt在膀胱移行细胞癌中的表达与肿瘤增殖能力,病理分级及临床分期的关系。方法：应用免疫组织化学技术分析77例膀胱移行细胞癌组织p16INK4,p21WAF/CIP1,p53mlt基因的表达和增殖细胞核抗原（PCNA）表达情况,并与病理分级及临床分期之间进行综合分析。结果：p16INK4,p21WAF/CIP1,p53mlt在膀胱移行细胞癌中的表达及PCNA增殖指数与肿瘤的病理分级有关,与临床分期无关。p16,p21,p53阳性组与阴性组分别比较,其PCNA增殖数之间有差异性。多因素分析发现,p16INK4和p21WAF／CIP1阴性及p53mlt阳性组的PCNA值明显高于p16INK4和p21WAF／CIP1阳性及p53mlt阳性组,两者比较不同病理分级的阳性表达构成比亦有显著性差异。结论:联合检测p16INK4,p21WAF/CIP1,p53mlt基因的表达情况能充分反映膀胱移行细胞癌的增殖能力及生物学行为,对膀胱移行细胞癌患者的预后判断及治疗有指导意义。     

胃癌组织cyclinE和p21~(WAF1/CIP1)蛋白表达的意义

目的 :探讨cyclinE和p2 1WAF1/CIP1蛋白在胃癌发生发展中的作用及其表达的意义。方法 :采用免疫组化S P法检测正常胃黏膜、萎缩性胃炎伴肠上皮化生、萎缩性胃炎伴不典型增生各 2 0例和 78例胃腺癌组织中cyclinE和 p2 1WAF1/CIP1蛋白表达。结果 :cyclinE蛋白阳性表达在胃癌组高于正常胃黏膜、萎缩性胃炎伴肠上皮化生组 ,而 p2 1WAF1/CIP1蛋白表达则相反 ,差异均有显著性 (P <0 0 5 ) ;cyclinE、p2 1WAF1/CIP1蛋白表达与胃癌细胞分化程度相关 (P <0 0 5 ) ;有肝转移的胃癌组cyclinE阳性表达率高于无肝转移组 (P <0 0 5 ) ;有淋巴结转移组 p2 1WAF1/CIP1蛋白表达率低于无淋巴结转移组 (P <0 0 5 )。结论 :cyclinE蛋白高表达与 p2 1WAF1/CIP1蛋白失表达可能参与胃癌的发生发展过程 ,检测cyclinE和p2 1WAF1/CIP1蛋白作为反映胃癌病理学特点的参考指标可能有一定意义     

大肠癌组织p14ARF与p53基因变异研究

目的：观察大肠癌组织p14ARF基因遗 传和表观遗传变化及p53基因突变状况，探讨两者改变的关系及p14ARF-p53通路功能 破坏在大肠癌发生中的作用。方法：应用PCR、直接测序、甲基化特异PC R和RT-PCR分别检测56例原发性大肠癌及相应癌旁正常组织p14ARF基因纯合性缺失、 突变、5′CpG岛甲基化、mRNA表达及p53基因突变状况。结果：①大肠 癌组织p14ARF总变异率为27% (15/56)，其中1例纯合性缺失，14例5′CpG岛甲基化,未见突变发生。②15例p14ARF基因变异的大肠癌组织其相应mRNA表达阴性（13例）或 低水平表达（2例），41例未发生基因变异的大肠癌组织和所有癌旁正常组织p14ARF mRNA均显示明显表达。③大肠癌组织p53突变率为48% (27/56)。④56例大肠癌组织中，12例 仅发生p14ARF变异，24例仅显示p53突变，3例同时有p14ARF 5′CpG岛甲基化 和p53突变，17例p14ARF和p53均无变异，p14ARF-p53通路总变异率为70%（39/ 56），p14ARF 5′CpG岛高甲基化与野生型p53状态有关（P＜0.05）。⑤低分化 腺癌组p14ARF变异率（44%，7/16）明显高于高中分化腺癌组（20%，8/40）（P＜ 0.05），但两组间p53突变率无显著差异（P＞0.05）。结论:①大肠癌p14ARF基因5′ CpG岛高甲基化是其表达失活的主要机制；②大肠癌p14 ARF基因高甲基化与p53基因突变可能是相互独立的事件，两者的失活可能各自出现于不同 的大肠癌亚组中；③p14ARF高甲基化或p53突变引起的p14ARF-p53通路功能 破坏在大肠癌的发生中具有重要作用。     

肺癌组织中HSG、p21和PCNA的表达及意义

目的 探讨细胞增殖抑制基因(HSG)、p21WAF1、增殖细胞核抗原(PCNA)在肺癌中的表达及其相关性.方法 采用免疫组化SP法检测92例肺癌(鳞、腺癌)组织中HSG、p21WAF1和PCNA的表达.结果 HSG在肺癌组织中的表达与组织学分型、分化程度有关(P<0.01、P<0.001);p21WAF1在肺癌组织中的表达与分化程度、淋巴结转移有关(P<0.001、P<0.01);PCNA在肺癌组织中的表达与分化程度、淋巴结转移有关(P<0.001).HSG与p21WAF1在肺癌组织中的表达呈正相关(r=0.34,P<0.05);HSG与PCNA在肺癌组织中的表达呈负相关(r=-0.41,P<0.05);p21WAF1与PCNA在肺癌组织中的表达呈负相关(r=-0.49,P<0.05).结论 HSG、p21WAF1和PCNA的表达与肺癌的发生、发展密切相关.     

p53、p21~(WAF1)蛋白在非小细胞肺癌中的表达及其临床意义

目的　探讨原发性非小细胞肺癌中p5 3、p2 1WAF1蛋白表达与临床病理及预后的关系。方法　应用免疫组织化学 (SP法 )方法。共检测非小细胞肺癌 147例 ,其中腺癌 6 6例 ,鳞癌 6 3例 ,腺鳞癌 14例 ,大细胞癌 4例。结果　p5 3蛋白总阳性率为 6 1.2 % (90 / 147) ,腺癌为 5 7.6 % (38/ 6 6 ) ,鳞癌阳性率为 6 3.5 % (4 0 / 6 3) ,腺鳞癌为 71.4% (10 / 14) ,大细胞癌 2例阳性。p2 1WAF1蛋白总阳性率为40 1% (5 9/ 147) ,腺癌为 42 .4% (2 8/ 6 6 ) ,鳞癌为 41.3% (2 6 / 6 3) ,腺鳞癌 2 8.6 % (4 / 14) ,大细胞癌 1例阳性。肺腺癌p5 3蛋白阳性表达与其预后相关 ,6 6例腺癌中 ,生存率低于 3年组和高于 3年组的p5 3蛋白阳性率分别为 75 % (2 1/ 2 8)和 44 .7% (17/ 38) ,差异有显著性意义 (P <0 .0 2 5 )。p2 1WAF1阳性表达与肺癌预后有关 ,p2 1WAF1阳性表达者 3年生存率 (6 4.4% )高于阴性表达者 (4 6 .6 % ) (P <0 .0 5 )。p5 3阳性而p2 1WAF1阴性的非小细胞肺癌患者的预后比p5 3阴性而p2 1WAF1阳性者差 (P <0 .0 1)。结论　检测p5 3蛋白表达可作为判断肺腺癌预后的指标之一 ;检测p2 1WAF1蛋白表达有利于对非小细胞肺癌预后的判断 ;联合检测p5 3、p2 1WAF1蛋白对判断非小细胞肺癌的预后有重要的意义 ,似可作     

皮肤瘢痕及瘢痕癌组织中cyclin A、p21WAF1的表达及意义

目的 探讨cyclin A、p21WAF1在皮肤病理性瘢痕和瘢痕癌组织中的表达及意义.方法 以病理性皮肤瘢痕、皮肤瘢痕癌组织为研究对象,以正常皮肤组织为对照.采用免疫组化SP法分别检测cyclin A、p21WAF1蛋白的表达,采用核酸分子原位杂交法检测cyclin A mRNA、p21WAF1 mRNA的表达,结合图像分析,分别观测3组被检组织中所检各项指标的表达(平均光密度和阳性面积);所有数据输入计算机后运用SPSS 16.0软件包进行统计学分析.结果 (1)cyclin A、cyclin A mRNA在正常皮肤表皮和病理性皮肤瘢痕上皮中的表达呈阴性或弱阳性,在瘢痕癌组织中呈强阳性.瘢痕癌组的表达(平均光密度和阳性面积)与正常皮肤组及皮肤瘢痕组比较,差异均有统计学意义(P＜0.01),但正常皮肤组与瘢痕组比较,差异无统计学意义(P＞0.05).(2)p21WAF1蛋白、p21WAF1 mRNA在正常皮肤表皮和病理性皮肤瘢痕上皮中的表达呈阴性或弱阳性,在瘢痕癌组织中呈强阳性.瘢痕癌组的表达(平均光密度和阳性面积)与正常皮肤组及皮肤瘢痕组比较,差异均有统计学意义(P<0.01),但正常皮肤组与瘢痕组比较,差异无统计学意义(P>0.05).(3)相关分析显示,在皮肤瘢痕癌中,cyclin A 与cyclin A mRNA(r=0.766,P<0.01)、p21WAF1与p21WAF1 mRNA(r=0.791,P<0.01)的表达呈正相关;cyclin A与p21WAF1蛋白(r=0.656,P<0.01)的表达呈正相关;cyclin A mRNA与p21WAF1 mRNA的表达呈正相关(r=0.475,P<0.05).结论 (1)cyclin A及其mRNA的高表达,可能与皮肤瘢痕癌的发生有关;(2)在瘢痕癌中,cyclin A、p21WAF1同时存在蛋白水平和基因水平的异常表达;(3)p21WAF1及其mRNA在瘢痕癌中的高表达可能与细胞周期调控的反馈机制有关.     

p21WAF1/CIP1 expression in colorectal carcinoma correlates with advanced disease stage and p53 mutations

Defects in the mechanisms controlling the cell cycle are crucial in cell transformation and/or tumour progression. p21^WAF1/CIP1 is an inhibitor of cyclin-dependent kinases, induced by p53-dependent and p53-independent pathways, which can block progression through the cell cycle. p21^WAF1/CIP1 expression has been investigated immunohistochemically in a series of 191 patients with colorectal cancer of known p53 status. The purpose of the study was two-fold: to assess the relationship between p21^WAF1/CIP1 immunoreactivity and p53 alterations, and to evaluate the prognostic significance of p21^WAF1/CIP1 expression. In 96 carcinomas (51 per cent), p21^WAF1/CIP1 was expressed in over 10 per cent of tumour cells, whereas in 26, p21^WAF1/CIP1 was detected in under 10 per cent of neoplastic cells; 69 tumours lacked p21^WAF1/CIP1 expression. Immunoreactivity was more frequent in tumours of the right colon (p < 0·003) and was inversely correlated with tumour stage (p < 0·03), p53 gene mutations (p < 0·0007), p53 protein accumulation (p < 0·019), and Bcl-2 expression (p < 0·0005). In univariate analysis, down-regulation of p21^WAF1/CIP1 expression was associated with poor overall (p = 0·0022) and disease-free survival (p = 0·0009). Multivariate analysis, however, did not confirm any independent prognostic significance of p21^WAF1/CIP1 expression. The results indicate that p21^WAF1/CIP1 is associated with abnormal accumulation of p53 protein and the occurrence of p53 gene mutations in colorectal cancer and that lack of p21^WAF1/CIP1 expression is correlated with reduced patient survival in univariate analysis. These data underline the crucial pathogenetic role of the p53–p21^WAF1/CIP1 pathway in carcinomas of the large bowel. Copyright © 1999 John Wiley & Sons, Ltd.     

Immunohistochemical expression of mdm2 and p21WAF1 in invasive cervical cancer: correlation with p53 protein and high risk HPV infection

AIM: To investigate the immunocytochemical staining pattern of mdm2 and p21WAF1 proteins in invasive cervical cancer and to determine its relation with the expression of p53 and with the high risk HPV infection. METHODS: Immunocytochemistry for p53, mdm2, and p21WAF1 was performed in 31 paraffin embedded sections of invasive cervical cancer. The results were assessed by image analysis, evaluating for each protein the optical density of the immunostained area, scored as percentage of the total nuclear area. The presence of high risk human papillomavirus (HPV) infection was detected by using the polymerase chain reaction. RESULTS: Immunostaining for both mdm2 and p21WAF1 was correlated with p53 expression; however, the correlation between p53 and mdm2 (R = 0.49; p < 0.01) was more significant than between p53 and p21WAF1 (R = 0.31; p < 0.05); the less stringent correlation between p53 and p21WAF1 might reflect the p53 independent mechanisms of p21WAF1 induction. Similar average levels of p53, mdm2, and p21WAF1 immunostaining were found in the presence or absence of high risk HPV-DNA, without significant differences between the two groups. CONCLUSIONS: These data suggest that mdm2 and p21WAF1 proteins are expressed in invasive cervical cancer and that their immunocytochemical staining pattern is not abrogated by the presence of high risk HPV genomic sequences.     

Expression of p21WAF1/CIP1 in fetal and adult tissues: simultaneous analysis with Ki67 and p53.

AIMS: To determine the expression of p21WAF1/CIP1 in relation to the expression of Ki67 and p53 in various normal adult and fetal tissues, and to investigate its distribution throughout the cell cycle. METHODS: The expression of p21WAF1/CIP1 in relation to Ki67 and p53 was analysed in adult and fetal tissues using immunohistochemical techniques. Heat induced epitope retrieval techniques were used to characterise the presence of p21WAF1/CIP1 in different tissues, as well as to detect its distribution throughout the cell cycle. In addition, flow cytometry and western blotting were used to test whether the level of p21WAF1/CIP1 expression varied at different phases of the cell cycle in phytohaemagglutinin (PHA) stimulated lymphocytes. RESULTS: p21WAF1/CIP1 expression varied from one tissue to another, and it was restricted mainly to the squamous and glandular epithelium, where it appeared in association with p53. Human tissues in which p21WAF1/CIP1 was found showed a mutually exclusive topographical sequential expression between p21WAF1/CIP1 and Ki67. This was confirmed by double labelling studies, which showed that p21WAF1/CIP1 positive cells were in the G0 phase. Unlike these findings of a decline in p21WAF1/CIP1 expression after the G0 phase, PHA stimulated lymphocytes showed a level of p21WAF1/CIP1 expression that rose as the cell progressed through the cell cycle. CONCLUSIONS: The analysis of p21WAF1/CIP1 expression in relation to the status of p53 should take into account the existence of variable p21WAF1/CIP1 expression in different tissues. This could provide an explanation for the varying frequency of p53 mutations in tumours of different cellular origin. In tissues characterised by regular p21WAF1/CIP1 expression, it appears in a pattern that is consistent with the proposed role of this inhibitor of cyclin dependent kinases in cell cycle arrest-that of inducing cell differentiation. The conflicting results of in vivo and in vitro studies could support the hypothesis that microenvironmental conditions may influence the location of p21WAF1/CIP1 in different phases of the cell cycle.     

Prognostic significance of p21WAF1/CIP1, p27Kip1, p53 and E-cadherin expression in gastric cancer

BACKGROUND: Gastric carcinoma is characterised by numerous genetic and epigenetic alterations that influence cell cycle progression, apoptosis and DNA repair. These alterations include down-regulation of the cyclin-dependent kinase (CDK) inhibitors p21(WAF1/CIP1) and p27(Kip1), and mutations of the tumour suppressor protein p53 and the cell adhesion molecule E-cadherin. Combined evaluation of the prognostic significance of these alterations has not been reported in Mexican Mestizo patients. AIMS: To evaluate p21(WAF1/CIP1), p27(Kip1), p53 and E-cadherin protein expression, including mutant E-cadherin variants with deletion of exon 8 (del 8) or 9 (del 9), in gastric cancer from Mexican patients. METHODS: Immunohistochemistry for the above-mentioned markers, including mutation-specific E-cadherin antibodies, was carried out in 69 gastric carcinomas; expression levels were correlated with histotype, tumour stage and prognosis. RESULTS: Expression of p21(WAF1/CIP1) alone or in combination with p27(Kip1) or in the absence of p53 was associated with favourable prognosis. Staining of del 8 and del 9 E-cadherin was found exclusively in patients negative for p53 and positive for p21(WAF1/CIP1), suggesting that the p21(WAF1/CIP1) regulatory function of p53 was intact. CONCLUSION: Combined evaluation of the prognostic significance of cell cycle regulators and E-cadherin should be performed. Even though patients negative for p53 and positive for p21(WAF1/CIP1) have a favourable prognosis, it may have a negative influence on prognosis if they acquire in addition E-cadherin mutations which have been shown previously to be associated with poor survival.     

p21WAF1/CIP1 expression in gestational trophoblastic disease: correlation with clinicopathological parameters, and Ki67 and p53 gene expression.

BACKGROUND: The p21WAF1/CIP1 gene mediates growth arrest by inhibiting G1 cyclin dependent kinases and has been considered as a downstream effector of the tumour suppressor gene p53. AIM: To analyse the role of p21WAF1/CIP1 in gestational trophoblastic disease. METHODS: The immunohistochemical expression of p21WAF1/CIP1 gene was measured in 33 placentas, 28 partial hydatidiform moles, 54 complete hydatidiform moles, and 13 choriocarcinomas in paraffin wax embedded tissue. The results were correlated with p53 (DO7) and Ki67 (MIB1) immunoreactivity as well as clinical progress. RESULTS: p21WAF1/CIP1 immunoreactivity was found predominantly in the nuclei of the syncytiotrophoblasts. p21WAF1/CIP1 protein expression correlated with gestational age in normal placentas (p = 0.0001) but not in hydatidiform moles (p = 0.89). Complete hydatidiform moles and choriocarcinomas had a significantly higher p21WAF1/CIP1 expression compared with normal placentas and partial hydatidiform moles (p < 0.001); there was no difference between placentas and partial hydatidiform moles. No correlation between p21WAF1/CIP1 expression and either the proliferation (Ki67) index (p = 0.34) or p53 protein accumulation (p = 0.68) was demonstrated. There was no significant difference (p > 0.05) in p21WAF1/CIP1 expression between the 17 patients who developed persistent gestational trophoblastic disease and those who did not. CONCLUSIONS: This study suggests that p21WAF1/CIP1 expression in trophoblastic disease may be induced by a p53 independent pathway. The proliferative activity of gestational trophoblastic diseases might not be determined solely by the control of the cell cycle operated by p21WAF1/CIP1. p21WAF1/CIP1 expression is not an accurate prognostic indicator of gestational trophoblastic disease.     

HDM2 overexpression and focal loss of p14/ARF expression may deregulate the p53 tumour suppressor pathway in meningeal haemangiopericytomas. Study by double immunofluorescence and laser scanning confocal microscopy

AIMS: To investigate the p53 pathway in meningeal haemangiopericytomas (MHPCs), p14/ARF, p53 protein expression and two wild-type (wt) p53-induced proteins (HDM2 and p21/WAF1) were studied in 18 MHPCs, 11 primary, four of them recurrent on one, one, two and four occasions. METHODS: Immunohistochemical detection of p14/ARF, p53, p21/WAF1, HDM2 and Ki67 proliferative index (PI) protein expression. RESULTS: Ki67 index was > 5% in eight out 18 cases (44.4%). The PI in recurrent cases increased with neoplastic progression. Simultaneous p53 and wt p53 transactivated gene (p21/WAF, HDM2) expression occurred in all cases. This argues against p53 mutation. HDM2 overexpression was observed in 10 cases (55.5%). Double-immunofluorescence staining and laser scanning confocal microscopy (LSCM) displayed HDM2 and p53 colocalization. This strongly suggests that HDM2 binds and inactivates p53 that could be pathogenic for MHPCs, by a different mechanism than point mutation. p14/ARF expression > 5% was observed in 12 cases (66.6%). A normal (diffuse) pattern of expression was seen in 13 cases (72.2%). Focal loss of expression was observed in five patients (27.7%): three primary cases and two recurrences. Therefore, p14/ARF down-regulation may also contribute to the development of MHPC. CONCLUSION: HDM2 overexpression, sometimes combined with focal loss of p14/ARF expression, may play a pathogenic role in MHPCs.