何杰金病中EB病毒感染和bcl—2蛋白的表达

目的探讨Ｅｐｓｔｅｉｎ－Ｂａｒｒ（ＥＢ）病毒与ｂｃｌ－２基因的关系。方法利用免疫组织化学ＬＳＡＢ法检测了６４例何杰金病ＥＢ病毒的潜在膜蛋白－１（ＬＭＰ－１）和ｂｃｌ－２蛋白的表达。用原位杂交方法检测了４１例何杰金病组织中的ＥＢＥＲ。又用双重染色的方法检测了７例ＥＢＥＲ和ｂｃｌ－２蛋白双阳性的何杰金病例。结果ＬＭＰ－１和ＥＢＥＲ的阳性率分别为３９％和４４％,所有ＥＢＥＲ阳性的病例ＬＭＰ－１均为阳性。ｂｃｌ－２蛋白的阳性率为２３％,其中仅有７例ＬＭＰ－１和ｂｃｌ－２蛋白同时阳性。双重染色结果为,在７例双阳性病例中ｂｃｌ－２阳性的细胞只有约５０％ＥＢＥＲ阳性,约４０％ＥＢＥＲ阳性的肿瘤细胞ｂｃｌ－２阳性。结论研究结果提示,在本组研究的病例中Ｒ－Ｓ细胞的ｂｃｌ－２蛋白的表达与ＥＢ病毒的存在与否无明显相关性。     

bcl-2、p53蛋白及PCNA表达与横纹肌肉瘤临床病理相关性研究

目的：研究横纹肌肉瘤（ＲＭＳ）中ｂｃｌ－２、ｐ５３、ＰＣＮＡ表达与其临床病理的相关性。方法：对５０例（随访４１例）横纹肌肉瘤进行免疫组化ＡＢＣ法标记。结果：ｂｃｌ－２、ｐ５３基因蛋白和ＰＣＮＡ，发现ｂｃｌ－２、ｐ５３、ＰＣＮＡ阳性表达率分别为２８％、７２％、７０％，其阳性表达与年龄、性别及不同组织类型的ＲＭＳ无关（Ｐ＞０．０５）。但与分化程度有关，ｐ５３、ＰＣＮＡ在低分化ＲＭＳ阳性率分别为８５％、９５％，显著高于高分化ＲＭＳ４２．８％和１４．３％（Ｐ＜０．０５），随访存活１年以内的ｐ５３、ＰＣＮＡ阳性率均为８６．７％，亦明显高于存活超过３年以上的阳性率３３．３％和４１．７％（Ｐ＜０．０５）。而ｂｃｌ－２在低分化ＲＭＳ阳性２０％显著低于高分化７１．４％（Ｐ＜０．０５），随访存活１年以内的阳性率１３．４％明显低于存活超过３年以上的４１．４％（Ｐ＜０．０５）。ｐ５３与ｂｃｌ－２阳性表达呈明显负相关，ｐ５３阳性率越高，而ｂｃｌ－２阳性率越低。结论：ＰＣＮＡ、ｐ５３、ｂｃｌ－２蛋白表达能比较准确地反映ＲＭＳ的生物学特性，ｐ５３、ｂｃｌ－２可作为肿瘤预后显著相关的有效指标。     

bcl—2,p53蛋白及PCNA表达与横纹肌肉瘤临床病…

目的：研究横纹肌肉瘤（ＲＭＳ）中ｂｃｌ－２、ｐ５３、ＰＣＮＡ表达与其临床病理的相关性。方法：对５０例横纹肌肉瘤进行免疫组化ＡＢＣ法标记。结果：ｂｃｌ－２、ｐ５３基因蛋白和ＰＣＮＡ，发现ｂｃｌ－２、ｐ５３、ＰＣＮＡ阳性表达率分别为２８％、７２％、７０％，其阳性表达与年龄、性别及不同组织类型的ＲＭＳ无关。但民分化程度有关，Ｐ５３、ＰＣＮ在低分化ＲＭＳ阳性率分别为８５％、９５％，显著高于 化ＲＭＳ４２．     

抗凋亡基因bcl—2在EB病毒相关性鼻咽癌中的表达

目的：探讨抗凋亡基因ｂｃｌ－２与鼻咽癌发生及与ＥＢ病毒感染的关系。方法：应用ＰＣＲ技术和免疫组化ＳＰ法检测４６例鼻咽癌组织中ＥＢ病毒ＤＮＡ和抗凋亡基因ｂｃｌ－２的表达。结果：３７例ＥＢ病毒ＤＮＡ阳性病例中３１例出现ｂｃｌ－２表达８３．８％，９例ＥＢ病毒ＤＮＡ阴性病例吸７例ｂｃｌ－２阳性反应，两组间无明显差异。结论：ｂｃｌ－２基因在鼻咽癌中的异常高表达与ＥＢ病毒的感染无明显关系。     

p53、c-erbB-2、PCNA和EGFR在膀胱癌中过表达及其意义

目的：研究癌基因和抑癌基因蛋白产物在膀胱移行细胞癌中异常表达与病理分级、临床分期、复发和预后的关系。方法：应用免疫组化Ｓ－Ｐ法检查１１７例膀胱移行细胞癌组织中ｐ５３、ｃ－ｅｒｂＢ－２、ＰＣＮＡ和ＥＧＦＲ的表达水平。结果：１１７例膀胱移行细胞癌中ｐ５３、ｃ－ｅｒｂＢ－２、ＰＣＮＡ和ＥＧＦＲ阳性表达率分别为４７．０％、２９．９％、５３．８％和４８．７％。ｐ５３和ＰＣＮＡ阳性表达产物定位于肿瘤细胞核内，ｃ－ｅｒｂＢ－２阳性表达产物定位于细胞膜上，ＥＧＦＲ阳性表达产物定位于细胞膜或细胞浆内。结果表明ｐ５３、ｃ－ｅｒｂＢ－２、ＰＣＮＡ和ＥＧＦＲ异常表达与膀胱癌的分级、分期、复发及术后生存率等之间有统计学意义。结论：ｐ５３、ｃ－ｅｒｂＢ－２、ＰＣＮＡ和ＥＧＦＲ异常表达有助于评估膀胱癌预后，多基因异常表达作为预后评价指标更有意义。     

胶质瘤p53、bcl-2、MDM2表达与细胞增殖和凋亡的关系

目的：研究胶质瘤中ｐ５３ 、ｂｃｌ２ 、ＭＤＭ２ 表达与细胞增殖和凋亡的关系。方法：对４８ 例胶质瘤用免疫组化法检测ｐ５３、ｂｃｌ２、ＭＤＭ２ 蛋白表达;以Ｋｉ６７ 标记指数和ＡｇＮＯＲ 计数检测其增殖活性;用ＴＵＮＥＬ 法检测细胞凋亡。结果：ｐ５３、ｂｃｌ２、ＭＤＭ２ 蛋白表达阳性率分别为４７－９ ％ 、３５－８ ％ 及１２－５ ％ ,细胞增殖活性随肿瘤ｐ５３ 、ｂｃｌ２、ＭＤＭ２ 表达水平增高而增高,细胞凋亡则相反。结论：ｐ５３、ｂｃｌ２、ＭＤＭ２ 蛋白过表达与细胞增殖失控、凋亡抑制关系密切,在胶质瘤恶性进展中起重要作用。     

p53,c—erbB—2,PCNA和EGFR在膀胱癌中过表达及 …

目的：研究癌基因和抑癌基因蛋白产物在膀胱移行细胞癌中异常表达与病理分级、临床分期、复发和预后的关系。方法：应用免疫组化Ｓ－Ｐ法检查１１７例膀胱移行细胞癌组织中ｐ５３、ｃ－ｅｒｂＢ－２、ＰＣＮＡ和ＥＧＦＲ的表达水平。结果：１１７例膀胱移行细胞癌中ｐ５３、ｃ－ｅｒｂＢ－２、ＰＣＮＡ和ＥＧＦＲ阳性表达率分别为４７．０％、２９．９％、５３．８％和４８．７％。ｐ５３和ＰＣＮＡ阳性表达产物定位于肿瘤细胞核内，     

bcl—2,p53蛋白在肺癌中的表达

目的：探讨ｂｃｌ－２和ｐ５３蛋白的异常表达与肺癌临床病理因素之间的关系。方法：应用免疫组化方法检测了术后随访５年以上的１２９例肺癌标本中ｂｃｌ－２、ｐ５３蛋白的表达。结果：ｂｃｌ－２及ｐ５３蛋白在肺癌中的阳性表达率分别为２８．７％和５２．７％，两种蛋白表达间呈显著正相关关系。在不同组织学类型中，两种蛋白阳性表达率间无显著差异。淋巴结癌转移阳性组中ｂｃｌ－２蛋白阳性表达率显著高于淋巴结转移阴性组（Ｐ     

人甲状腺髓样癌内凋亡细胞检测和bcl-2、p53及Ki-67的免疫组化研究

目的：检测甲状腺髓样癌内凋亡细胞、ｂｃｌ－２、ｐ５３和Ｋｉ－６７，探讨其与患者的预后关系。方法：在２１例甲状腺髓样癌内，用ＤＮＡ末端标记方法检测凋亡细胞和用免疫组织化学技术检测ｂｃｌ－２、ｐ５３及Ｋｉ－６７的表达。结果：在２１例甲状腺髓样癌标本中，凋亡细胞ｂｃｌ－２、ｐ５３和Ｋｉ－６７的检出率分别为８１％，１００％，６２％和７１％。ｂｃｌ－２阳性物质位于肿瘤细胞的胞浆内，少数病例则位于膜上。ｐ５３蛋白阳性主要位于胞核内，少数病例也同时见于胞浆内。Ｋｉ－６７抗原主要位于肿瘤细胞核内。本研究结果表明，ｂｃｌ－２和肿瘤细胞凋亡之间有密切关系（Ｐ＜０．０１）。ｂｃｌ－２阳性细胞检出率较高的病例，凋亡细胞检出率则较低；反之，凋亡细胞检出率则较高。ｐ５３和Ｋｉ－６７阳性细胞检出率和细胞凋亡无相关性（Ｐ＞０．０５）。结论：ｂｃｌ－２具有抑制细胞凋亡的作用。上述各因素检测结果与患者存活率无统计学意义。ｂｃｌ－２肿瘤蛋白在甲状腺髓样癌中高表达，可作为该肿瘤的一个新的标记物，对预后的判断可能也有一定的意义     

bcl-2、p53表达与乳腺癌预后的关系

目的：探讨ｂｃｌ２ 、ｐ５３ 表达与乳腺癌预后的关系。方法：应用免疫组化ＬＳＡＢ法检测６４ 例乳腺癌及３０ 例乳腺良性病变的表达。分析ｂｃｌ２、ｐ５３ 与乳腺癌组织学分级、腋淋巴结转移、复发和预后的关系。结果：ｂｃｌ２ 与ｐ５３ 表达之间差异有显著性,呈负相关（ Ｐ＜ ０－０５） 。ｂｃｌ２ 和ｐ５３ 表达与组织学分级有关（ Ｐ＜ ０－０５） ,ｂｃｌ２ 表达随分级增加阳性率降低,ｐ５３ 则相反。ｐ５３ 表达与腋淋巴结转移有关（ Ｐ＜ ０－０５） 。ｂｃｌ２ 表达与腋淋巴结转移无关（ Ｐ＞ ０－０５） 。ｐ５３ 表达复发组明显高于无复发组（ Ｐ＜０－０５）;ｂｃｌ２ 表达与有无复发无关（Ｐ＞０－０５）。ｐ５３ 表达阳性率≤５ 年生存组明显高于＞ ５ 年生存组,呈负相关（ Ｐ＜ ０－０５）;ｂｃｌ２ 表达与生存期无关（Ｐ＞ ０－０５） 。结论：ｂｃｌ２ 表达与预后无关,其阳性表达可反映肿瘤属分化较好或属早期阶段。ｐ５３ 可单独作为预后指标;ｐ５３ 表达与预后呈负相关。     

Immunohistochemical analysis of bcl-2 and p53 expression in breast carcinomas: their correlation with Ki-67 growth fraction

We examined 59 breast cancers for p53 and bcl-2 protein expression by immunohistochemistry. The results were correlated with Ki-67 immunostaining. p53-negativity was noted in 40 cases and the remaining 19 tumours were p53-positive. Thirty-six tumours showed strong expression of bcl-2 and in 23 no staining for this protein was observed. We found statistically significant reverse correlation between expression of p53 and bcl-2 in majority of carcinomas: 31 cases were bcl-2 positive and p53-negative, and 14 tumours were bcl-2-negative and p53-positive. Six carcinomas showed no nuclear staining for Ki-67 and in the remaining 53 the percent of cancer cells positive for Ki-67 ranged from 1 to 60 (mean: 14.6). In these 53 cases we found that bcl-2-positive tumours were characterized by lower proliferation than bcl-2-negative tumours, the mean value of Ki-67 immunostaining being 10.7% and 23.0%, respectively. p53-negative tumours showed lower proliferation than p53-positive tumours: mean Ki-67 index was 10.2% and 23.9%, respectively.We conclude that immunohistochemically detected p53 and bcl-2 proteins show a significant inverse relationship in majority of breast carcinomas and their expression correlates with tumour proliferation (Ki-67 immunostaining).     

鼻咽部原发性Burkitt‘s淋巴瘤与EB病毒的关系

研究鼻咽部原发性伯基特淋巴瘤与Ｅｐｓｔｅｉｎ－Ｂａｒｒ病毒的关系。应用单克隆抗体Ｌ２６（ＣＤ２０）,ＵＣＬＨ－１（ＣＤ４５ＲＯ）,ＣＳ１－４潜伏膜蛋白和ＥＢ病毒核抗原２进行免疫组织化学染色,寡核苷酸探针ＥＢＥＲ原位杂交及双标记方法,观察其免疫表型及ＥＢ病毒的检出及定位情况。     

Immunohistochemical detection of p53 and Bcl-2 proteins in Hashimoto's thyroiditis and primary thyroid lymphomas.

AIMS--To investigate whether immunohistochemical staining using p53 and/or bcl-2 distinguishes between florid Hashimoto's thyroiditis and low grade mucosa associated lymphoid tissue (MALT) lymphoma of the thyroid. METHODS--Ten cases of Hashimoto's thyroiditis and eight of primary thyroid lymphoma were stained with monoclonal antibodies directed against p53 and bcl-2. RESULTS--In Hashimoto's thyroiditis most small lymphoid cells in mantle zones, within the thyroid parenchyma and in lymphoepithelial lesions expressed bcl-2 protein. Very occasional centroblasts in reactive germinal centres were positive for p53, but all other lymphoid cells from cases of Hashimoto's disease were negative for p53. In diffuse, low grade lymphomas bcl-2 protein was uniformly expressed by most tumour cells. However, low grade lymphomas with a follicular pattern did not express bcl-2. The diffuse, low grade lymphomas were negative for p53, while occasional larger cells in the follicular subtype were positive. Both high grade lymphomas were bcl-2 negative but strongly p53 positive. CONCLUSIONS--This study indicates that there is an inverse correlation between p53 and bcl-2 immunostaining in thyroid lymphomas (low grade lymphomas: bcl-2 positive, p53 negative; high grade lymphomas: bcl-2 negative, p53 positive). Furthermore, immunohistochemical staining for bcl-2 and p53 proteins does not distinguish florid Hashimoto's thyroiditis from diffuse, low grade thyroid lymphoma.     

Expression of epidermal and nerve growth factor receptors in human thymus and thymomas

We have investigated the immunohistochemical expression of p53 protein in 96 cases of non-Hodgkin's lymphoma using a panel of five antibodies. Positive neoplastic cells were found in 30 (31.2%) cases, which could be divided into two groups according to their patterns of reactivity with the different antibodies; i.e. those positive with both polyclonal and monoclonal antibodies, and those which were stained only by monoclonal antibodies PAb1801 and/or PAb240. Positivity was nuclear in all but six cases in which cytoplasmic staining was found. In view of the hypothesis recently raised that p53 protein induces apoptosis we have compared our results with parallel staining for bcl-2 protein since bcl-2 is believed to be important, at least in lymphomas, in suppression of apoptosis. Staining for bcl-2 protein was performed on 83 cases and it was shown that p53-positive cases accounted for 10 out of 17 (59%) of the bcl-2 -negative lymphomas but only for 15 out of the 66 (23%) bcl-2 -positive cases, suggesting a possible relationship between the expression of these two proteins. Thus, our data show that p53 protein is abnormally expressed in a substantial proportion of non-Hodgkin's lymphomas and bears a significant inverse relationship to bcl-2 protein expression. However the molecular basis of this expression remains to be elucidated.     

Loss of bcl-2 expression in ductal carcinoma in situ of the breast relates to poor histological differentiation and to expression of p53 and c-erbB-2 proteins

Aim : This study (1) investigates the incidence of bcl-2 protein expression in a series of 108 cases of ductal carcinoma in situ (DCIS), including 25 with early invasive carcinoma, and (2) evaluates the relationship of bcl-2 expression to the histological grade of DCIS and to the expression of oestrogen receptor (ER), c-erbB-2 and p53 proteins.  

Methods and results

The expression of bcl-2, oestrogen receptor (ER), c-erbB-2 and p53 proteins was determined immunohistochemically. Cases were regarded as positive for individual antibodies when at least 10% of the DCIS cells showed positive staining. DCIS was graded histologically as well ( n  = 9), intermediately ( n  = 24), or poorly differentiated ( n  = 75). bcl-2 expression was documented in 57 cases (53%) and was strongly associated with the histological grade of DCIS ( P  < 0.0001). All cases of well-differentiated DCIS were bcl-2 positive and loss of bcl-2 expression was almost exclusively confined to poorly differentiated DCIS lesions. bcl-2 expression was also closely associated with positive ER status ( P  < 0.0001). Forty-seven of 57 (82%) bcl-2 positive cases were ER positive while 49/51 (96%) bcl-2 negative cases were ER negative. There was a significant inverse correlation between bcl-2 expression and both p53 protein expression ( P  = 0.0004) and c-erbB-2 expression ( P  < 0.0001). Nineteen of 24 (79%) p53 positive cases and 38/45 (84%) c-erbB-2 positive cases showed loss of bcl-2.  

Conclusions

Loss of bcl-2 expression occurs in poorly differentiated DCIS and is related to negative ER status and to positive p53 and c-erbB-2 status. This pattern of bcl-2 expression and its association with other biological markers in DCIS is similar to that reported in invasive breast carcinoma.     

bcl-2和p53表达在结直肠癌预后评估中的价值

目的　探讨bcl 2和 p5 3表达水平与结直肠癌肿瘤生物学特征及其预后的关系。 方法　应用免疫组化S P法 ,检测93例结直肠癌标本中bcl 2与p5 3蛋白的表达 ,并与临床病理特征进行相关分析。结果　bcl 2蛋白在结直肠癌的阳性表达率为 5 7 0 % (5 3/ 93) ,与淋巴结转移呈负相关 (P <0 0 1) ,p5 3表达阳性率为 4 3% (4 0 / 93) ,与淋巴结转移无相关 (P >0 0 5 ) ,但p5 3表达阳性患者的预后差于 p5 3阴性组 (P =0 0 1)。当分析bcl 2和 p5 3联合表达时 ,Dukes分期及淋巴结转移各组间有差异 (P <0 0 5 )。其中bcl 2 (+) / p5 3(- )表达形式多见于DukesA和B期肿瘤 (4 1 0 % ,2 3/ 5 6 )。经Cox模型多因素分析结果表明 ,淋巴结转移 (P <0 0 1)和 p5 3表达 (P <0 0 1)是结直肠癌独立预后影响因素。其他指标 ,包括bcl 2和 p5 3联合表达情况等均未显示出统计学意义。结论　bcl 2和p5 3表达水平可提示结直肠癌的生物学行为 ,但bcl 2的表达与淋巴结转移状况相关不是一个单独作用的预后指标 ,而 p5 3虽与其它生物学特性关系不大 ,却是一个相对独立的结直肠癌预后指标。     

T细胞淋巴瘤1和CD44蛋白在Burkitt淋巴瘤中的表达及其诊断价值

目的 探讨T细胞淋巴瘤1(TCL1)和CD44蛋白在Burkitt淋巴瘤中的表达及其诊断价值.方法 在石蜡包埋的实验组25例Burkitt淋巴瘤和对照组25例非特指弥漫性大B细胞淋巴瘤(DLBCL)中采用免疫组织化学EnVision法检测CD44、TCLl以及CD10、bel-2、bcl-6、c-myc、Ki-67等常用抗体表达情况.结果 Burkitt淋巴瘤中瘤细胞96%(24例)呈TCL1阳性,仅4%(1例)CD44阳性;88%(22例)CD10阳性、92%(23例)bcl-6和c-myc阳性,仅4%(1例)bcl-2阳性;Ki-67增殖指数为95%～100%.非特指DLBCL中仅16%(4例)TCL1弱阳性,84%(21例)CD44阳性、32%(8例)CD10阳性、72%(18例)bcl-6和bcl-2阳性、c-myc均阴性,Ki-67增殖指数40%～90%.结论 当形态和免疫表型不典型时,TCL1和CD44两种蛋白的检测有助于提高Burkitt淋巴瘤的确诊率及其与DLBCL的鉴别诊断.     

Pitfalls in the diagnosis of ectopic hamartomatous thymoma

We have investigated the immunohistochemical expression of p53, mdm2, p21/waf1 and bcl-2 proteins in 31 thymic epithelial tumours comprising five medullary thymomas (MDT), four mixed thymomas (MT), 12 cortical thymomas (CT), eight predominately cortical thymomas (PCT) and two well-differentiated thymic carcinomas (WDTC). We have found p53, mdm2, p21 and bcl-2 protein expression in 25/31, 8/31, 5/31 and 10/31 thymic epithelial tumours, respectively. Coexpression of p53 and mdm2 proteins was found in eight cases (three CT, four PCT and one WDTC). Five of them were also p21 positive and three p21 negative. Discordant p53+/mdm2−/p21− protein expression was found in 19 cases (three MDT, three MT, nine CT, three PCT and one WDTC). Mdm2 and p21 proteins were not expressed in the absence of p53 protein. Coexpression of bcl-2 and p53 proteins was found in seven cases (three MDT, three MT and one WDTC). Eighteen cases were p53+/bcl-2− (10 CT, seven PCT and one WDTC) and three cases (two MDT and one MT) were bcl-2+/p53−. Our findings indicate that in thymomas, p53 expression is more frequently associated with cortical histotypes while bcl-2 expression is strongly associated with medullary and mixed histotypes. In addition, there is an inverse correlation between p53 and bcl-2 protein expression in thymomas. Coexpression of p53/mdm2/p21 proteins may reflect thymomas with wild-type (wt), p53 gene since mdm2 and p21 proteins are inducible by wt p53 gene. However, in view of previous findings that p53 mutation is an early event in thymomas, the possibility of p53 gene mutation with p53-independent mdm2 and p21 expression should be considered in these cases. Discordant p53+/mdm2−/p21− protein expression may represent thymomas with p53 gene mutations unable to activate expression of mdm2 and p21 proteins.     

Expression of p53 and bcl-2 and response to preoperative chemotherapy and radiotherapy for locally advanced squamous cell carcinoma of the oesophagus.

AIMS: To investigate the immunohistochemical expression of p53 and bcl-2 proteins in squamous cell carcinoma (SCC) of the oesophagus and to assess whether expression of these oncoproteins can be used to stratify patients into groups with a favourable or unfavourable response to preoperative chemo/radiotherapy. METHODS: The initial diagnostic biopsy and the corresponding resected samples were obtained from 22 consecutive patients with SCC. All patients underwent preoperative chemo/radiotherapy. Tumour sections were incubated with a monoclonal antibody directed against p53 (DO-7). Twenty four non-neoplastic oesophageal biopsy specimens immunostained for p53 served as controls. Twelve randomly chosen sections from the 22 SCC samples were immunostained to test for bcl-2 protein expression. RESULTS: After chemo/radiotherapy, 12 (55%) of the 22 patients had no evidence of tumour in the resected oesophagus. Before chemoradiotherapy, however, 17 (77%) patients were p53 positive. After treatment, residual carcinoma was detected in seven (41%) of the 17 p53 positive patients. All non-responsive cases had the same p53 immunopattern as before treatment. Bcl-2 immunoexpression was detected in six (50%) of 12 patients. Residual tumour was detected in the residual oesophagus in two (33%) of the six bcl-2 positive patients. After treatment, bcl-2 expression was no longer detected in the residual neoplastic cells of a previously bcl-2 positive tumour. Using Fisher's exact test no significant association was found between oncoprotein expression and response to preoperative treatment. CONCLUSION: This study confirms the observation that p53 protein is frequently expressed in SCCs of the oesophagus, probably as a result of a mutation of the TP53 gene. However, no significant association was found between oncoprotein expression and response to chemo/radiotherapy. Anticancer agents do not seem to modify the expression of p53 and bcl-2 proteins.