Apoptosis and expression of Bax, Bcl-x, and Bcl-2 apoptotic regulatory proteins in colorectal carcinomas, and association with p53 genotype/phenotype.

AIMS: Spontaneous apoptosis and expression of the apoptotic regulatory proteins Bax, Bcl-x, and Bcl-2 were investigated in 50 colorectal carcinomas. The p53 genotypes/phenotypes and BAX genotypes were also determined, and possible associations of these with apoptosis and/or with expression of the different apoptotic regulatory proteins were studied. METHODS: Terminal deoxynucleotidyl transferase (TdT) mediated dUTP labelling of DNA fragments was used to detect apoptotic tumour cells in sections and peroxidase immunohistochemistry was used to assess protein expression. p53 genotype/phenotype was determined using constant denaturant gel electrophoresis/immunoblotting and bax genotype was determined using polymerase chain reaction based methods. RESULTS: The distribution of tumour apoptotic indices was bimodal with a natural cut off at 1.0% (range, 0.0-5.4%); the median fraction of apoptotic tumour cells was 0.8%. Tumour apoptosis was not associated significantly with tumour DNA ploidy status. Normal mucosal tissue had less than 0.1% apoptotic cells. Staining intensities for Bax, Bcl-x, and Bcl-2 were strong; that is, equivalent to or greater than positive normal mucosal cells, in 11 of 50, 20 of 49, and 20 of 48 carcinomas. Frameshift mutations in the bax gene were detected in three of 42 tumours analysed, all of which were DNA diploid, and Bax protein expression in these tumours was absent or very low. Bax, Bcl-x, and Bcl-2 protein expression were not correlated with tumour apoptosis or tumour DNA ploidy status. p53 was expressed in 34 of 50 tumours and p53 gene mutations were detected in 22 of 29 p53 positive tumours analysed. Apoptosis was significantly lower in a greater number of p53 positive tumours than p53 negative tumours. In addition, Bcl-2 protein expression was significantly higher in a greater number of p53 positive tumours compared with p53 negative tumours. Bax and Bcl-x protein expression were not significantly associated with p53 phenotype/genotype. CONCLUSIONS: The results indicate that acquisition of a p53 phenotype is associated with lower spontaneous apoptosis and higher expression of Bcl-2. The results also suggest that p53 is not a major determinant for Bax expression in colorectal carcinomas in vivo.     

Immunohistochemical expression of Bcl-2, Bcl-x, and Bax in follicular carcinomas of the thyroid.

Bcl-2, bcl-x, and bax proteins are involved in the regulation of apoptosis. There is limited data on the expression of these proteins in follicular carcinomas (FCs) of the thyroid. A retrospective clinicopathologic review with bcl-2, bcl-x, and bax immunostaining of 34 FCs and 7 follicular adenomas with incomplete capsular penetration (FAICP) was performed. The study included 41 patients (25 females; age range 16 to 84 y, mean 50.9 y). All patients underwent surgical resection. Seven FC patients developed recurrent disease: 1 patient was alive (14.2 y) and 6 patients died with metastatic disease (mean survival 5.9 y). All remaining patients were disease-free (mean follow-up 7.9 y). Only one FAICP recurred (patient alive at 11 y). The remaining patients were disease-free (mean follow-up 6.9 y). Normal thyroid tissue stained positively for bcl-2 and bcl-x, and did not stain with bax. Only 15 tumors (12 FC and 3 FAICP) stained positively for bcl-2. None of the recurrent tumors demonstrated evidence of bcl-2 staining. The majority of tumors stained positively for bax (83%, 29 FC and 5 FAICP) and for bcl-x (93%, 32 FC and 6 FAICP); there was no correlation of staining with outcome. The majority of follicular neoplasms were positive for bax and negative for bcl-2 by immunohistochemistry. Aberrant expression of apoptosis-associated proteins may play a role in the pathogenesis of FC of the thyroid. All recurrent and fatal tumors were negative for bcl-2. These data suggest that the loss of bcl-2 expression may correlate with poorer prognosis.     

The expression of Bcl-2 family proteins (Bcl-2, Bcl-x, Bax, Bak and Bim) in human lymphocytes

Bcl-2 family proteins regulate programmed cell death, and may play an important role in the selection of lymphocytes. We investigated the expression of Bcl-2, Bcl-x, Bax, Bak and Bim in human lymphocytes using flow-cytometry. Bcl-2 was down-regulated in CD4(+)8(+) (DP) thymocytes and CD19(+)38(+) tonsillar lymphocytes (GC B cells). Among DP thymocytes, cells co-expressing CD69 up-regulated Bcl-2, suggesting that the role of Bcl-2 is promoting survival of positively selected DP cells. Unexpectedly, the expression level of Bcl-x was higher in DP cells than in Single Positive (SP) cells and in CD69(+) DP thymocytes it was lower than in CD69(+) DP thymocytes. Expression of Bim was low in DP thymocytes but high in a subset of GC B cells. Bim and Bax were expressed more highly in SP than in DP thymocytes. Among peripheral blood lymphocytes (PBL), CD8(+) T cells expressed an approximately ten-fold higher level of Bcl-x than CD4(+) T cells while both subsets expressed similar levels of Bcl-2. Bak expression was low and Bim expression was absent in PBL. These results suggest that not only Bcl-2 but other members of the Bcl-2 family are involved in T cell development in the thymus and affinity maturation of B cells in the germinal center.     

DCC基因在大肠癌中的表达及与Bcl-2, Bax关系

目的：探讨DCC(deleted in colorectal carcinoma)基因在大肠癌组织中的表达情况及与Bcl-2，Bax蛋白之间的关系。 方法：采用免疫组织化学法结合图像分析技术观察74例大肠癌组织中DCC，Bcl-2，Bax蛋白的表达情况。 结果：大肠癌组织中，DCC蛋白失表达率为 54.1% (40/74)，其表达在不同的肿瘤分化程度 (P＝0.002)及Dukes分期中有差异 (P＝0.042)； Bcl-2蛋白表达阳性率为60.8% (45/74)，其表达与不同的大肠癌临床Dukes分期 (P＝0.032)及是否有淋巴结转移 (P<0.001)中有差异；Bax蛋白表达阳性率为48.6% (36/74)，在不同的大肠癌组织学类型、分化程度、Dukes分期及淋巴结是否转移中均无差异 (P>0.05)。大肠癌中DCC蛋白表达与Bcl-2表达水平呈负相关（r＝－0.201, P＝0.043），与Bax表达水平呈正相关（r＝0.296, P＝0.005）。 结论：大肠癌中DCC表达缺失频率较高，且可能通过上调Bcl-2蛋白表达和下调Bax蛋白表达阻止细胞凋亡，从而促进大肠癌发生。     

Bcl-2, Bax and Bcl-x expression following kainic acid administration at convulsant doses in the rat.

Neuronal death was produced in the CA1 and CA3 areas of the hippocampus, amygdala, and piriform and entorhinal cortices after intraperitioneal administration of kainic acid at convulsant doses to adult rats. To assess the involvement of members of the Bcl-2 family in cell death or survival, immunohistochemistry, western and northern blotting to Bcl-2, Bcl-x and Bax, and in situ hybridization to Bax were examined at different time-points after kainic acid treatment. Members of the Bcl-2 family were expressed in the cytoplasm of pyramidal neurons in the hippocampus, and in a subset of neurons of the piriform and the entorhinal cortices, amygdala and neocortex in the normal adult brain. Dying neurons in the pyramidal cell layer of CA1 and CA3 areas, entorhinal and piriform cortices, and amygdala also expressed Bcl-2, Bax and Bcl-x following excitotoxicity, although many dying cells did not. In addition, a number of cells in the affected areas showed Bax immunoreactivity in their nuclei at 24-48 h following kainic acid administration, thus indicating Bax nuclear translocation in a subset of dying cells. Western blots disclosed no modifications in the intensity of the bands corresponding to Bcl-2, Bcl-x and Bax, between control and kainic acid-treated rats. No modifications in the intensity of the bcl-2 messenger RNA band on northern blots was observed in kainic acid-treated rats. However, a progressive increase in the intensity of the bax messenger RNA band was found in kainic acid-treated rats at 6 h, 12 h and 24 h following kainic acid administration. Interestingly, a slight increase in Bax immunoreactivity was observed in the cytoplasm of neurons of the dentate gyrus at 24-48 h, a feature which matches the increase of bax messenger RNA in the same area, as shown by in situ hybridization at 12-24 h following kainic acid injection. The present results suggest that cell death or survival does not correlate with modifications of Bcl-2, Bax and Bcl-x protein, and messenger RNA expression, but rather that kainic acid excitotoxicity is associated with Bax translocation to the nucleus in a subset of dying cells.     

Correlation of p53 protein expression with apoptotic incidence in colorectal neoplasia

The wild-type p53 gene suppresses cell proliferation and induces apoptosis when it is transfected into human colon cancer cell lines. Therefore, mutation of the p53 gene, which correlates closely with p53 protein overexpression, would be predicted to activate cell proliferation and limit apoptosis. We tested this hypothesis by correlating p53 protein expression with cell proliferation and apoptosis in 70 neoplasms (29 adenomas and 41 carcinomas) using p53 and Ki-67 immunohistochemical staining and DNA nick end labelling. The p53 immunoreactivity was independent of the Ki-67 positivity. The apoptotic incidence was less frequent (P<0.005) in tumours with diffuse p53 protein overexpression than in those with the sporadic overexpression, defined as p53 staining of isolated or scattered expression. In addition, apoptotic incidence only correlated directly (P<0.05) with Ki-67 positivity in tumours with sporadic p53-protein expression. These results indicate that p53 protein that is expressed sporadically in colorectal neoplasms is probably wild-type protein and induces apoptosis in response to active cell proliferation. In contrast, diffusely overexpressed p53 protein in colorectal neoplasms is probably mutant and correlates with a reduction in apoptotic cell death independently of cell proliferation.     

生育年龄妇女早期卵泡细胞凋亡和Bcl-2/BAX蛋白表达

目的:研究生育年龄妇女早期卵泡的细胞凋亡和Bcl-2/BAX蛋白表达。方法:12例卵巢组织标本来自进行妇科手术的生育年龄妇女(年龄23-38岁),并经过组织病理学检查证实无明显形态异常。利用末端标记法(TUNEL)和免疫组织化学方法研究早期卵泡(包括始基卵泡、间期和初级卵泡)细胞凋亡和Bcl-2/BAX蛋白表达。结果:早期卵泡内18.75%卵细胞表现TUNEL阳性,但是卵泡内未见TUNEL阳性颗粒细胞。BAX在早期卵泡的卵细胞内表达,阳性表达率76.07%;相反未见Bcl-2在卵细胞表达。另外,早期卵泡内颗粒细胞也没有表达Bcl-2和BAX。结论:生育年龄妇女早期卵泡的卵细胞发生凋亡,促凋亡蛋白BAX在卵细胞凋亡过程中发挥调节作用,由此提示BAX介导的卵细胞凋亡可能是生育年龄妇女早期卵泡闭锁的机制。     

Bcl-2 and p53 expression in insular and in well-differentiated thyroid carcinomas with an insular pattern

Expression of p53 and bcl-2 oncogenes was investigated in poorly differentiated, so-called insular carcinomas of the thyroid gland and also in the follicular and papillary carcinomas with an insular component. Hematoxylin-eosin sections of 217 thyroid carcinomas were reevaluated for insular carcinoma and also for thyroid carcinomas with an insular component. Immunohistochemical staining method was used for detecting p53 and bcl-2 expression on paraffin blocks of three pure insular, five follicular or papillary thyroid carcinomas with a major insular component (more than 50%) and six with a minor insular component (20–50%). Flow cytometry was also performed in these cases. None of the cases showed p53 immunoreactivity. Bcl-2 expression was observed in all cases and the most intense staining was seen in insular areas. All the cases were diploid. We suggest that bcl-2 plays a role in loss of differentiation of thyroid carcinomas.     

Bcl-2, tissue transglutaminase and p53 protein expression in the apoptotic cascade in ribs of premature infants

Apoptotic cells of the human growth plate have not previously been demonstrated in situ. We have investigated the distribution of apoptotic cells in costosternal growth plates and bone of premature infants aged 4–11 d with a gestational age of ∼ 26 wk. In addition, we investigated the immunolocalisation of apoptosis-related proteins within the growth plates and associated bone. A proportion of late hypertrophic chondrocytes and osteocytes within newly formed primary spongiosa showed evidence of highly fragmented DNA. The incidence of osteocyte apoptosis decreased as the distance from the chondroosseous junction increased. Tissue transglutaminase (tTG) expression was associated with apoptosis of osteocytes and hypertrophic chondrocytes. In contrast the presence of tTG was demonstrated in osteoblasts and bone lining cells but it did not colocalise with evidence of apoptosis. The anti-apoptotic gene product Bcl-2 was absent from the growth plate but was present in osteocytes. Visual assessment indicated a greater occurrence of the protein in cells occupying regions of low apoptosis. P53 was not demonstrated in the growth plate or bone. These findings would indicate that human growth plate chondrocytes appear to show little provision for ensuring cell longevity. In contrast osteocyte apoptosis appears negatively correlated with the skeletal distribution of Bcl-2 protein in the human infant, implying a potential selective vulnerability in individual cells. Lack of Bcl-2 and the high incidence of osteocyte apoptosis in the more rapidly remodelling bone of the human infant suggest a potential role of osteocyte apoptosis in the remodelling process.     

Bcl-2, Bcl-x, and Bax expression by immunohistochemistry in inclusion body myositis: a study of 27 cases

CONTEXT: Bcl-2, Bcl-x, and Bax are among the variety of proteins that have been described as being involved in the regulation of apoptotic cell death. Bcl-2 and Bcl-x(L) inhibit apoptosis, and Bax is proapoptotic. OBJECTIVE: To evaluate the expression of Bcl-2, Bcl-x, and Bax in inclusion body myositis (IBM).Design.-We examined muscle specimens from 27 patients (17 men, 10 women) with IBM to evaluate Bcl-2, Bcl-x, and Bax expression by immunohistochemistry. RESULTS: Patient ages ranged from 29 to 80 years (mean 62.2 years). All biopsies were marked by endomysial chronic inflammation, muscle fiber necrosis, and regeneration. Rimmed (autophagic) vacuoles were present in all cases. Ragged red fibers were noted in 4 biopsies (15%), and cytochrome oxidase-deficient fibers were found in 10 biopsies (37%). Ultrastructural evidence of intranuclear or cytoplasmic tubulofilamentous inclusions, confirming the diagnosis of IBM, were noted in all cases. Paracrystalline mitochondrial inclusions were seen in 5 biopsies (18.5%). Inflammatory cells stained positively with Bcl-2 in all biopsies, Bax in 26 biopsies (96%), and Bcl-x in 8 biopsies (30%). Degenerating muscle fibers were highlighted with Bax in 24 biopsies (89%), Bcl-2 in 2 biopsies (7%), and Bcl-x in 3 biopsies (11%). Regenerative muscle fibers were noted to stain with Bax in 24 muscles (89%), Bcl-2 in 21 muscles (78%), and Bcl-x in 4 muscles (15%). Rimmed vacuoles were highlighted by Bax in 24 biopsies (89%) and only rarely by Bcl-2 (n = 2, 7%) and Bcl-x (n = 3, 11%). A subsarcolemmal staining pattern was observed in 21 biopsies (78%) with Bax, 6 biopsies (22%) with Bcl-2, and only 1 biopsy (4%) with Bcl-x. CONCLUSIONS: (1) Bax (proapoptotic) immunostaining highlighted most autophagic vacuoles; (2) subsarcolemmal Bax and Bcl-2 immunoreactivity may be associated with mitochondrial defects that are commonly noted in IBM; (3) Bcl-2 and Bax immunoreactivity were not confined to degenerating muscle fibers and in fact appeared to be expressed more commonly in regenerating fibers, suggesting that their expression may be independent of apoptosis in the setting of IBM.     

中药髓复康对恒河猴脊髓半横断后凋亡相关蛋白表达的影响

目的:探讨中药髓复康(SFK)对恒河猴脊髓半横断后凋亡相关蛋白(Bcl-2、Bax和p53)表达的作用及其机理。方法:实验选用8岁恒河猴14只,随机分为中药治疗组6只、横段脊髓模型组6只、正常对照组2只,采用双盲法复制脊髓T12右侧半横断损伤模型。灌喂SFK溶液1月后,实验恒河猴麻醉、以损伤部位为中心切取长1cm的脊髓,采用常规SABC免疫组织化学方法检测凋亡相关基因Bcl-2、Bax和p53蛋白表达,并对结果进行定性、定位、图像分析和统计学处理。结果:脊髓Bax免疫组织化学阳性细胞的平均光密度(MOD)模型组略高于正常对照组,中药组明显低于模型组(P0.05)。脊髓Bcl-2免疫组织化学阳性细胞面数密度(NA),中药组明显高于模型组(P0.05)。脊髓Bcl-2免疫组织化学阳性细胞的MOD模型组略高于正常对照组,中药组略高于模型组。脊髓p53免疫组织化学阳性细胞NA,模型组明显高于正常对照组(P0.05),中药组明显低于模型组(P0.05)。脊髓p53免疫组织化学阳性细胞的MOD模型组明显高于正常对照组(P0.05),中药组明显低于模型组(P0.05)。结论:髓复康可以促进Bcl-2蛋白表达,抑制Bax、p53蛋白表达和抑制神经元凋亡,对脊髓神经损伤具有保护作用。     

Apoptosis in gestational trophoblastic disease is correlated with clinical outcome and Bcl-2 expression but not Bax expression.

Apoptosis has been found to play a crucial role in the pathogenesis and prognosis of many human diseases. The pathogenesis of gestational trophoblastic disease (GTD), which encompasses hydatidiform moles (HMs) and choriocarcinomas (CCAs), is not fully understood. Prognostic indicators of HM have also been scanty. In this study, we investigated apoptotic activity and the expression of two apoptosis regulatory genes, Bcl-2 and Bax, in an attempt to determine the role of apoptosis in GTD. Formalin-fixed paraffin-embedded tissue of 33 normal placentas, 14 spontaneous abortions, 14 partial moles, 34 complete moles, and eight CCAs were examined. Apoptotic activity was assessed by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) method. Quantitative assessment of apoptotic index (AI) was calculated as a percentage of TUNEL-positive nuclei. Expression of Bcl-2 and Bax were assessed immunohistochemically. Extensive apoptosis was located in syncytiotrophoblasts, cytotrophoblasts, and villous stromal cells in all HM cases. Apoptosis was detected at a much lower level in spontaneous abortions and normal placentas. Moreover, in normal placentas, TUNEL positive nuclei were exclusively found in syncytiotrophoblasts. AIs were significantly different among various categories of trophoblastic lesions (P < .001) in an ascending order: normal placentas less than spontaneous abortions less than CCAs less than HMs. Furthermore, AIs of those cases that spontaneously regressed was statistically higher than those that developed persistent trophoblastic disease requiring chemotherapy. AIs of trophoblastic lesions in general inversely correlated with Bcl-2 expression (P < .001), but no significant correlation was found between AI and Bax expression (P > .5). We conclude that AI may be a useful prognostic marker for clinical progress of HMs. Bcl-2 expression is probably regulating apoptosis in normal placentas and GTD, whereas Bax expression is not. The difference in AI and Bcl-2 expression between non-molar placentas and HMs offers a potential adjunctive diagnostic tool to distinguish the two entities.     

Bax,Bcl-2, fas and Fas-L antigen expression in human seminoma: correlation with the apoptotic index

Apoptosis plays a crucial role in the regulation of spermatogenesis in male germ cells and is, at least in part, modulated by Bcl-2, Bax, and the Fas pathway. Seminomas have a favourable outcome and respond to radio-/chemotherapy with an increased rate of apoptosis. The expression of Bax, Bcl-2, Fas and Fas-ligand (Fas-L) in human seminoma was evaluated and correlated with the apoptotic index. Twenty-nine classical seminomas were examined by immunohistochemistry and Western blotting using antibodies against Bax, Bcl-2, Fas and Fas-L. Apoptosis was detected by in-situ end-labeling of fragmented DNA and the apoptotic index (AI) was determined. Expression of Fas was found in 26 (89.7%) of Fas-L in 24 seminomas (82.2%); none of the tumours expressed Bcl-2. No correlation between the AI and Fas, Fas-L or Bcl-2 expression was found. Bax was demonstrated in 20/29 tumours (69%). Bax-positive tumours showed an increased AI of 4.75 +/- 2.38% in contrast to 2.60 +/- 1.23% of the Bax-negative tumours (P = 0.002). The number of Bax-positive tumour cells and apoptotic cells revealed a significant correlation using chi2-test (P = 0.04) and linear regression (r = 0.54, P = 0.001). Therefore, Bax seems to play a determinant role in the modulation of apoptosis in human seminoma that may be linked to a favourable outcome.     

p53 expression in colorectal tumors.

The expression of the nuclear phosphoprotein p53 was studied immunohistochemically in a series of 150 benign and malignant colorectal tumors. Using monoclonal antibody PAb1801, tumors divided unequivocally into two groups on the basis of immunohistochemistry. Forty of the carcinomas (46.5%) showed positive staining but only 4 of the adenomas (8.7%) were positive (P less than 0.001). The few positive adenomas always showed moderate or severe dysplasia. Metaplastic polyps (n = 9) and small familial adenomatous polyposis-related adenomas (n = 9) were uniformly negative. Carcinomas with p53 expression did not differ from those without in terms of site, differentiation or the prognostic indicators of Dukes' stage, DNA ploidy, or tumor histology. The improved morphologic resolution available in periodate lysine paraformaldehyde dichromate (PLPD)-fixed, paraffin-embedded tissue permitted several conclusions to be made: p53 is confined to neoplastic nuclei; staining in positive tumors is heterogeneous and often more marked at the infiltrative margins; and staining intensity is dramatically reduced in mitotic cells. It is concluded that expression of immunohistochemically detectable p53 (probably representing mutated forms of the protein) occurs in some adenomas around the time of transition to carcinoma. Therefore there is an association with the appearance of infiltrative behavior but not with degree of tumor progression (including metastasis) at the time of resection.     

Apoptosis and proliferation related molecules (Bcl-2, Bax, p53, PCNA) in papillary microcarcinoma versus papillary carcinoma of the thyroid

AIM: To gain a better insight into the differences in biological behaviour between papillary microcarcinoma (PMC) and clinically evident papillary thyroid carcinoma (PTC). METHODS: Immunohistochemical analysis of apoptosis related molecules (Bcl-2, Bax, p53) and proliferation related marker (PCNA) in 39 archival cases of PMC and 46 cases of PTC. RESULTS: Bcl-2 and Bax were expressed in most PMCs and PTCs. The average Bcl-2 staining score did not differ significantly between PMCs and PTCs (p > 0.05), but the average Bax score was significantly lower in PMCs (p < 0.05). The Bcl-2/Bax ratio was significantly higher in PMCs than in PTCs (p < 0.05). The expression of p53 was similar in PMCs and PTCs, without a correlation with clinical data, but was associated with high Bax expression (p < 0.05) in these cases in both groups. Non-malignant tissue expressed only Bcl-2, but not p53 or Bax. PCNA expression was significantly lower (p < 0.05) in PMC than in PTC and positively correlated with tumour size (p < 0.05). CONCLUSIONS: The higher Bcl-2/Bax ratio and lower proliferative activity in PMC suggest differences from PTC in the balance between apoptosis and proliferation. However, the presence of p53 and Bax in PMC indicates malignant potential, and thus PMC should be treated with caution.     

p53 expression in colorectal adenomas.

To assess the expression of p53 in premalignant lesions, we examined by immunohistochemistry benign colorectal adenomas (n = 72, measuring more than 6 mm and less than 95 mm in diameter) from patients without (group I, n = 23) or with (group II, n = 49) concurrent sporadic colorectal carcinomas. Using a panel of three monoclonal antibodies (PAb 240, PAb 421, PAb 1801) and two polyclonal antibodies (CM1, C19) immunohistological staining was demonstrated in 26% of the cases (19 of 72 adenomas, 7 of 23 from group I and 12 of 49 from group II). In the majority of the cases, p53 positive foci in the adenomas occurred in the most dysplastic areas, although focal positivity was detected in glands that were histologically normal. Expression of p53 protein was also detected in 21 of 30 (70%) colorectal carcinomas of group II. In two cases focal positive staining was observed in the polyps but not in the concurrent carcinomas. Non-neoplastic colonic mucosa and stromal lymphoid cells were negative in all cases examined. Over-expression of p53 in neoplastic tissues detected by immunocytochemistry is generally believed to correlate with the presence of mutation in the gene. This may not be an absolute rule, because in some hemopoietic malignancies, there is evidence that p53 protein may be detectable in the absence of an underlying mutation. These findings therefore represent the highest incidence in colorectal adenomas of abnormalities in the p53 protein expression, probably largely due to underlying mutations. This study also suggests that immunocytochemical demonstration of p53 protein may be a suitable method for the routine detection of subpopulations of cells which, by clonal expansion, could acquire a growth advantage within an adenoma during the neoplastic process.     

MDM-2 protein expression in nasopharyngeal carcinomas. Comparative study with p53 protein expression

Aims—To investigate the immunohistochemical expression of MDM-2 protein in comparison with that of p53 protein in nasopharyngeal carcinomas.     

腰椎肥厚黄韧带中细胞凋亡及凋亡因子caspase-3、fas、p53的表达

文题释义： 黄韧带：由左右两部分组成,韧带上下分别附着于上位椎板的前下方,下位椎板的上缘,连接椎弓板,参与围成椎管,控制脊柱过度前屈,维持脊柱稳定。黄韧带肥厚可造成椎管管腔减小及椎间孔狭窄,硬膜囊和脊神经根的压迫,从而产生临床症状。 免疫组织化学技术：是用标记的特异性抗体(或抗原)对组织内的抗原(或抗体)的分布进行定位、定性、定量检测,经过组织化学呈色反应在组织原位显示抗原(或抗体),如各种蛋白质、多肽、磷脂和多糖等成分的一门技术。 背景：腰椎管狭窄症是造成老年人步态紊乱和腰腿痛的关键原因之一,黄韧带肥厚是导致腰椎管狭窄症的主要病理机制,目前关于黄韧带的影像学及病理研究较多,关于细胞凋亡的研究较少。                                                   目的：检测肥厚黄韧带组织中的细胞凋亡率及凋亡因子caspase-3、fas、p53的表达,为深入了解黄韧带退变的机制提供实验依据。          方法：实验组50个经MRI及术后测量证实肥厚黄韧带标本(L₂-S₁)来自50例腰椎管狭窄症行后路减压手术自愿捐赠的患者,男22例,女28例,年龄32-74岁,平均54.46岁;对照组30个经MRI及术后测量证实非肥厚黄韧带标本(L₂-S₁)来自30例腰椎间盘突出症行手术及腰椎爆裂骨折行手术患者,男19例,女11例,年龄19-67岁,平均47.27岁。采用TUNEL染色法检测黄韧带中的凋亡细胞率,用SP免疫组织化学法检测caspase-3、fas、p53的表达。研究通过了新疆医科大学第六附属医院伦理委员会批准,伦理编号为LFYLLSJ2016007。                                           结果与结论：①TUNEL染色示实验组的平均凋亡细胞率高于对照组[(37.80±3.04)%,(13.18±1.34)%,t=41.83,P < 0.001];②SP免疫组织化学染色示实验组caspase-3、fas、p53阳性表达率均为100%,对照组caspase-3、fas、p53阳性表达率为13.3%,16.7%,10%,两组比较差异均有统计学意义(P < 0.001)。结果表明,腰椎肥厚黄韧带组织中细胞凋亡增加,肥厚黄韧带中细胞凋亡与caspase-3、fas、p53的表达上调具有一定的相关性。 ORCID: 0000-0002-0539-5510(张方新) 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

Bcl-2 and p53 protein expression, apoptosis, and p53 mutation in human epithelial ovarian cancers

Bcl-2 and p53 gene products have been both linked to cell death by apoptosis. In the present study, we examined the relationship of Bcl-2 and p53 protein expression, p53 mutation and apoptosis in normal human ovaries and different types of human ovarian epithelial tumors by immunohistochemical localization, in situ terminal transferase-mediated dUTP nick end labeling and polymerase chain reaction-single strand conformation polymorphism. It was found that Bcl-2 expressed strongly in the surface epithelium of normal ovaries and benign and borderline ovarian tumors but weakly in the malignant tumors. On the contrary, strong protein expression of p53 was found in 54% (25/46) of the malignant epithelial tumors examined but similar expression of p53 was not observed in borderline and benign tumors and normal ovarian surface epithelium. A significant inverse correlation between Bcl-2 and p53 expression was found in the malignant ovarian tumors examined. p53 gene mutation at exons 5-11 was however not a pre-requisite for p53 expression in both borderline and malignant tumors. Apoptotic activities, as reflected by apoptotic indices, were low in normal ovarian surface epithelium and benign tumors but were increased in borderline and malignant tumors, with the highest average apoptotic index found in grade III malignant tumors. Statistical analyses showed a positive correlation between apoptosis and p53 expression, but similar correlation was not found between apoptosis and Bcl-2 expression. Our results also indicate that although expression of Bcl-2 is important during ovarian carcinogenesis, the Bcl-2 protein may have other roles to play apart from being a modulator of apoptosis in human ovarian epithelial cancers.