Ki-67和PCNA表达与乳腺癌及乳腺癌化疗敏感性的关系

目的:探讨分析乳腺癌组织中核增殖相关抗原(Ki-67)及增殖细胞核抗原(PCNA)表达变化与乳腺癌的关系及其对乳腺癌化疗敏感性的关系,为临床乳腺癌的有效化疗提供理论依据。方法:实验对象取自于近年来我院收治的、经临床检查确诊为乳腺癌患者84例,利用免疫组化方法分别测量其乳腺癌组织中的Ki-67及PCNA的含量,比较不同Ki-67及PCNA表达水平的患者接受化疗疗效的差异。结果:Ki-67阳性例数为52例,PCNA阳性例数为62例。Ki-67阳性率与患者淋巴结转移及肿瘤分型分期呈正相关,差异有统计学意义,P<0.05。而PCNA阳性率与肿瘤淋巴结转移成正相关,P<0.05,与肿瘤临床分型分期无关,P>0.05。Ki-67+总有效率为80.8%明显高于Ki-67-的56.2%,P<0.05。PCNA-有效率为72.7%明显高于PCNA+的45.2%,P<0.05。结论:Ki-67及PCNA表达与乳腺癌临床资料及其化疗敏感性密切相关,可以作为预测化疗疗效的指标。     

p53,Ki-67及E-钙黏蛋白在三阴性乳腺癌中的表达及预后

目的:探讨p53,Ki-67及E-钙黏蛋白(E-cadherin)在三阴性乳腺癌(triple negative breast cancer,TNBC)组织中的表达及预后的关系.方法:采用免疫组织化学法检测52例TNBC和52例非三阴性乳腺癌(non-triple-negative breast cancer,NTNBC)组织中p53,Ki-67及E-cadherin表达情况,观察3个指标与TNBC患者临床病理学特征及预后的关系.结果:TNBC组织中p53,Ki-67及E-cadherin的阳性表达率分别为67.3％,80.8％,26.9％;而在NTNBC组织中为44.2％,61.5％,48.1％(均P＜0.05).在TNBC组织中,p53表达阳性与肿瘤大小、TNM分期及组织学分级有关(均P＜0.05);Ki-67表达阳性与TNM分期、淋巴结转移有关(均P＜0.05);E-cadherin表达阳性与肿瘤大小、TNM分期、淋巴结转移有关(均P＜0.05).在TNBC患者中,p53,Ki-67及E-cadherin表达阳性者与阴性者总体生存率(overall survival,OS)的差异均有统计学意义(P＜0.05).Cox回归分析多因素显示:淋巴结转移、p53、Ki-67及E-cadherin表达是影响TNBC患者总体生存率的独立预后因素(均P＜0.05).结论:TNBC组织中,p53、Ki-67高表达,其表达阳性者预后差,E-cadherin低表达,其表达阳性者预后良好.联合检测p53、Ki-67及E-cadherin表达可为TNBC患者的治疗提供新靶点.     

P57和Ki-67在葡萄胎鉴别诊断中的作用

目的:探讨P57和Ki-67蛋白在完全性和部分性葡萄胎鉴别诊断中的作用.方法:分别收集正常胎盘绒毛、部分性葡萄胎和完全性葡萄胎石蜡标本各12例,应用免疫组织化学方法检测P57和Ki-67蛋白在这些病变中的分布及表达水平.结果:P57蛋白在正常绒毛及部分性葡萄胎组织中主要分布于绒毛的细胞滋养叶细胞及间质细胞,两组间阳性率...     

非小细胞肺癌中Ki-67和BCL-2表达的临床意义及预后价值

目的 探讨细胞增殖核抗原Ki-67蛋白及凋亡调节因子BCL-2蛋白在非小细胞肺癌(non-small cell lung carcinoma,NSCLC)中表达.方法 采用组织芯片技术用Ki-67和BCL-2单克隆抗体对261例NSCLC标本进行免疫组化染色.结果 Ki-67增殖指数为61.3%,在8例正常对照组织中呈阴性;Ki-67蛋白表达在高分化组明显低于低分化组、淋巴结转移阳性组明显高于淋巴结转移阴性组,差异均有显著性(P＜0.01);Ki-67表达与患者年龄、性别、组织类型和T分期无关;Ki-67阳性组患者平均存活月数明显低于阴性组,差异有显著性(P<0.01).BCL-2蛋白阳性率为43.68%,对照组阴性;BCL-2在低分化组和淋巴结转移阳性组分别低于高分化组和淋巴结转移阴性组,差异均无显著性(P>0.05);BCL-2阳性组患者平均存活月数高于阴性组患者,差异无显著性(P>0.05);BCL-2蛋白表达与患者年龄、性别、组织学类型、T分期无关;114例BCL-2阳性患者中Ki-67阳性率仅26.88%,而101例Ki-67阴性患者中BCL-2阳性率为70.30%.结论 BCL-2表达与NSCLC临床病理因素无相关性,Ki-67与BCL-2表达呈明显负相关.Ki-67蛋白作为细胞增生标志与NSCLC淋巴结转移相关,Ki-67阳性者预后差,Ki-67可作为判断NSCLC预后的一个有价值的分子标志.     

乳腺癌和非癌组织中Syk、survivin和Ki-67的表达及其相关性

目的 探讨乳腺癌和非癌组织中Syk、survivin和Ki-67的表达及其相互关系.方法 应用免疫组化SP法检测52例乳腺浸润性导管癌和39例非癌组织(包括癌旁乳腺组织17例和乳腺纤维腺瘤组织22例)中Syk、survivin和Ki-67的表达.结果 39例非癌组织中Syk均呈阳性表达,而survivin及Ki-67均呈阴性表达.52例乳腺癌组织中,Syk阳性22例(42.3%),survivin阳性36例(69.2%),Ki-67阳性32例(61.5%).乳腺癌中Syk阳性表达率低于非癌组织(χ2=31.01, P＜0.01);乳腺癌中survivin(χ2=41.82,P＜0.01)和Ki-67(χ2=34.37,P＜0.01)阳性表达率均高于非癌组织.相关分析显示,Syk与survivin的表达呈负相关(r=-0.53,P＜0.01);Syk与Ki-67的表达相关系数呈负值(r=-0.22,P=0.12);survivin与Ki-67的表达呈正相关(r=0.33,P＜0.05).结论 Syk可能有抑制乳腺癌细胞增殖和促进其凋亡的功能,提示Syk可能是一种抑癌基因,可作为乳腺癌新的分子标记物.联合检测Syk、survivin和Ki-67在乳腺癌中的表达,有望成为估价乳腺癌生物学行为的参考指标.     

EGFR和Ki-67在肠癌组织中的表达及临床意义

目的:探讨表皮生长因子受体(epidermal growth factor receptor,EGFR)和Ki-67在结直肠癌(colorectal cancer,CRC)组织中的表达及临床意义.方法:应用免疫组织化学染色检测100例CRC组织中EGFR和Ki-67蛋白的表达,并分析其与临床病理特征的关系.结果:EGFR,Ki-67在CRC中的阳性表达率分别为70.0％,85.0％.EGFR的阳性表达在结直肠癌的不同分化程度和TNM分期中差异有统计学意义(P＜0.05),与淋巴结转移呈正相关(P＜0.05).Ki-67的表达与结直肠癌组织分化程度、淋巴结转移和肿瘤原发部位有关(P＜0.05).在CRC组织中,Ki-67与EGFR蛋白呈显著正相关(r=0.581,P＜0.001).结论:EGFR和Ki-67蛋白的表达与组织分化程度及淋巴结转移密切相关,二者的联合检测有助于结直肠癌恶性程度的判断和预后的估计.     

PCNA和Caspase-3在妊娠滋养细胞疾病中的表达及意义

目的研究PCNA和Caspase-3在妊娠滋养细胞疾病中的表达变化及意义,为妊娠滋养细胞疾病早期诊断、预后判断提供理论依据。方法收集滋养细胞疾病标本50例,其中葡萄胎10例(均为完全性葡萄胎),侵蚀性葡萄胎20例,绒毛膜癌20例。正常早孕绒毛标本10例为对照组。应用免疫组织化学技术检测PCNA和Caspase-3在早孕绒毛、葡萄胎、侵蚀性葡萄胎、绒毛膜癌组织中的表达情况。结果 PCNA在正常早孕绒毛、葡萄胎、侵蚀性葡萄胎和绒癌中的表达分别为10.24%、20.70%、50.92%、53.65%,各组差异有统计学意义(P0.05)。Caspase-3在正常早孕绒毛、葡萄胎、侵蚀性葡萄胎和绒癌中的表达先升高又降低,分别为1.25%、2.60%、6.40%、1.90%,各组差异有统计学意义(P0.05)。结论 PCNA及Caspase-3表达异常,增殖/凋亡失衡是引起GTT的重要因素。     

PCNA和P57^kip2在葡萄胎中表达的研究

目的探讨PCNA（增殖细胞核抗原,proliferation cell nuclear antigen）和P57^kip2在CM（完全性葡萄胎,com-plete hydatidiform mole）及PM（部分性葡萄胎,partial hydatidiform mole）中的表达及意义。方法应用免疫组化的方法检测PCNA及P57^kip2蛋白在CM、PM及HA（水肿绒毛,hydrops trophonema）组织中的表达。结果 PCNA在所有组织切片中均见到。PCNA主要在细胞滋养层细胞及中间型滋养细胞表达。PI在HA中最低,于PM中增高,CM中达到最高。其中CM与PM及与HA之间,差异均有统计学意义（P〈0.05）。而PM与HA之间无显著性差异（P〉0.05）。P57^kip2在30例HA27例呈阳性表达（90%）,30例PM 25例呈阳性表达（83.33%）,28例CM 3例呈阳性表达（10.71%）,并且在CM中的阳性强度均较弱。3种病变P57^kip2染色阳性率统计分析显示CM与PM及HA之间均存在显著性差异（P〈0.01）,而PM与HA之间无显著性差异（P〉0.05）。结论 PCNA与P57^kip2能代表葡萄胎滋养细胞异常增生的客观指标,P57^kip2蛋白的低表达和PCNA的高表达可能在葡萄胎的的发生发展中起重要作用,两者的共同检测对早期CM的发现有重大作用。     

p57和p53蛋白在水肿性流产及葡萄胎鉴别诊断中的作用

目的探讨p57和p53蛋白在水肿性流产、完全性和部分性葡萄胎鉴别诊断中的作用。方法分别收集正常绒毛、水肿性流产、部分性葡萄胎和完全性葡萄胎石蜡标本10、12、23和20例,应用免疫组织化学EnVision法检测p57和p53蛋白在这些组织中的分布及表达水平。结果p57蛋白在正常绒毛、水肿性流产及部分性葡萄胎组织中主要分布于绒毛的细胞滋养细胞及间质细胞,阳性表达比例分别为10/10、12/12和100％( 23/23),各组间相比差异无统计学意义(P＞0.05)。在完全性葡萄胎中细胞滋养细胞及间质细胞p57表达缺失,与部分性葡萄胎相比,差异有统计学意义(P＜0.05)。p53蛋白主要表达于完全性和部分性葡萄胎的细胞滋养细胞及中间滋养细胞。在正常绒毛中p53蛋白呈阴性表达,水肿性流产中仅1例p53蛋白呈阳性表达(1/12),部分性葡萄胎和完全性葡萄胎中p53蛋白的阳性率分别为60.9％( 14/23)和85.0％ (17/20);p53蛋白的阳性率,部分性葡萄胎较水肿性流产明显增加,完全性葡萄胎较部分性葡萄胎也明显增加,差异均有统计学意义(均P ＜0.05)。结论p57蛋白免疫组织化学检测可辅助鉴别完全性和部分性葡萄胎,而p53蛋白的检测则有助于鉴别水肿性流产和部分性葡萄胎。     

子宫内膜癌中Rb2/P130、PTEN及Ki-67的表达及意义

目的 探讨正常子宫内膜、子宫内膜增殖症及内膜癌组织中Rb2/P130、PTEN及Ki-67的表达以及与子宫内膜癌发生的关系.方法 应用免疫组化SP法检测30例正常子宫内膜组织、32例单纯型增生过长、31例复杂型增生过长、36例不典型增生、64例子宫内膜癌组织中Rb2/P130、PTEN和Ki-67的表达.结果 Rb2/P130、PTEN蛋白在正常子宫内膜、单纯性增生过长、复杂型增生、不典犁增生、子官内膜癌组织中的阳性表达率依次递减,而Ki-67的阳性表达率依次递增,子宫内膜癌和不典型性增生中Rb2/P130、PTEN阳性表达率明显低于正常增生期子宫内膜和单纯性增生,差异均有显著性(P均<0.01),而Ki-67的阳性表达率明显高于正常增牛期子宫内膜和单纯性增生过长,差异均有显著性(P均<0.01).Rb2/P130、PTEN阳性表达缺失与组织学分级有关(P均<0.01)、与子宫肌层浸润程度无关,Rb2/P130阳性表达缺失与淋巴结转移无关,PTEN阳性表达缺失与淋巴结转移有关(P<0.05),而Ki-67阳性表达与组织学分级、临床分期及淋巴结转移有关(P<0.01,P<0.05,P<0.01),与子宫肌层浸润程度无关.Rb2/P130、PTEN蛋白表达与Ki-67呈负相关(P<0.003.P<0.000).结论 Rb2/P130、PTEN蛋白与Ki-67的异常表达与子宫内膜癌的发生相关,有可能成为子宫内膜组织早期癌变的有用标记物.     

Use of proliferation cell nuclear antigen immunoreactivity for distinguishing hydropic abortions from partial hydatidiform moles.

AIMS: To determine whether the expression of proliferating cell nuclear antigen (PCNA) in villous cytotrophoblast could distinguish between placental tissue from a hydropic abortion and that from a partial hydatidiform mole. METHODS: Tissue from 18 partial hydatidiform moles, 15 hydropic abortions, five normal first trimester placentas and five normal full term placentas were immunostained for expression of PCNA, using the monoclonal antibody PC10. RESULTS: PCNA immunoreactivity was very much higher in the cytotrophoblast of normal first trimester placentas than in normal term placentas. Villous tissue from partial hydatidiform moles showed, on average, less immunoreactivity for PCNA than did villous tissue from hydropic abortions. CONCLUSIONS: Immunostaining for PCNA is of no value for differentiating between partial hydatidiform moles and hydropic abortions. The findings indicate that trophoblastic proliferation or hyperplasia is not a feature of partial hydatidiform moles.     

Minichromosome maintenance protein 7 expression in gestational trophoblastic disease: correlation with Ki67, PCNA and clinicopathological parameters

AIMS: To assess the proliferative activity of gestational trophoblastic disease (GTD) using one of the novel proliferation markers (MCM7) and to determine its prognostic value in hydatidiform mole (HM). METHODS AND RESULTS: Immunohistochemical staining for MCM7 was performed on 122 samples of paraffin-embedded trophoblastic tissues including 22 normal first-trimester placentas, 12 term placentas, 12 spontaneous miscarriages (SM), 21 partial moles (PM), 44 complete hydatidiform moles (CM), and 11 choriocarcinomas (CCA). The correlations between the proliferative indices assessed by MCM7, proliferating cell nuclear antigen (PCNA) and Ki67 (MIB1) immunoreactivity as well as clinical progress were assessed. MCM7 immunoreactivity was found predominantly in the nuclei of cytotrophoblast and intermediate trophoblast and decreased with placental maturation. MCM7 expression was highest in CCA, followed by CM, PM, normal first-trimester placenta, SM and term placenta. MCM7 index was significantly higher in PM and CM than in SM (P = 0.007, P < 0.001) but not between PM and CM themselves (P = 0.560). Eighteen of the 65 patients with HM developed persistent trophoblastic disease (PTD) requiring chemotherapy. There was no significant difference in MCM7 indices between the patients who developed PTD and those who did not (P = 0.312). MCM7 indices correlated well with Ki67 (P = 0.002) but not with PCNA (P = 0.054) indices. MCM7 indices demonstrated less variability than PCNA and Ki67 and may be a better proliferation marker than the latter two. CONCLUSIONS: We conclude that MCM7 is useful in differentiating molar and non-molar gestations but is not helpful in discriminating PM from CM or in predicting PTD.     

The Journal of Histotechnology Volume 9, March 1986 – December 1986

Abstract

We analyzed the relationship between tumor proliferation and expression of PCNA, whose role as a proliferative marker remains controversial. Bivariate DNA/PCNA flow cytornetric analysis of both clonogenic cell lines and several human tumor and normal samples were compared to Ki-67 immunostaining. Because there are 2 populations of PCNA in cells, a replicon-bound and a free nucleoplasmic form, PCNA labeling was strongly affected by the cell fixation procedure used: poor with paraformaldehyde, strong and uniform with methanol, and variable with acetone1 methanol. Only the acetonelmethanol fixation demonstrated good correlation between S-phase specificity and cell proliferation marker. Cells blocked in specific cell cycle phases were distinguished by different staining levels; PCNA expression was detectable from early G1, increased in late G1, reached a maximum in S, and remained high in G2M. Because of its long half-life, residual levels of PCNA were still detectable in G0, whereas expression of the proliferative marker Ki-67, expressed later in the cell cycle than PCNA, was very weak or even undetectable in G0 cells and in early G1 cells. Staining levels of PCNA in tumor cells were always higher than in normal cells whatever their origin. Similarly, resting normal lymphocytes displayed lower PCNA levels than those observed in leukemia lymphoblasts. Fewer normal cells stained with Ki-67: PCNA labeling tended to give an overestimation of the growth fraction. Comparison between PCNA and Ki-67 labeling showed a linear correlation; but when compared in S-phase fraction, Ki-67 performed better than PCNA. PCNA may be used with caution and attention to fixation. It may be difficult to distinguish between proliferative and newly quiescecnetl ls, because of its residual prolonged expression. (The J Histotechnol 22:287, 1999)     

Gestational trophoblastic diseases: update on new immunohistochemical findings

Recent advances in the immunohistochemical analysis of gestational trophoblastic diseases allow pathologists to classify more accurately specific types of gestational trophoblastic lesions. The morphologic features of some forms of gestational trophoblastic tumours are dependent on the parental origin of the genetic contributions. Genomic imprinting results in the production of certain protein products based on the parental genetic origin. By analysing the protein product of an imprinted gene, such as p57^kip2, a hydatidiform mole may be classified as complete or partial. In addition, we review CD 34, p53, bcl-2, Bax, p21^waf1/cip1 and PCNA immunohistochemical expression in complete hydatidiform moles. A similar immunohistochemical review is performed for partial hydatidiform moles. We discuss the implications of various immunohistochemical findings in the nonvillous trophoblastic tumours: placental site trophoblastic tumour, epithelioid trophoblastic tumour and choriocarcinoma. Specific antibodies reviewed in detail for these lesions include inhibin-alpha, CK 18, MIB-1 (Ki-67), Mel-CAM, cyclins A, B, D1 and E, cdk 2 and 4, and p53. In summary, advances in immunohistochemistry aid the histopathologist in correctly classifying gestational trophoblastic tumours.     

Expression of c-myc and c-fms oncogenes in trophoblastic cells in hydatidiform mole and normal human placenta.

AIMS: To compare the expression of c-myc and c-fms proto-oncogenes in the placenta and hydatidiform mole. METHODS: Twelve hydatidiform moles and six induced abortion cases were collected. c-myc and c-fms proto-oncogene expression was analysed by northern blot hybridisation and immunohistochemical staining. RESULTS: The results of northern blot hybridisation analysis showed that c-fms was expressed more strongly in hydatidiform moles compared with normal placenta of similar gestational age. Moreover, c-fms mRNA concentrations increased with more advanced gestational age in moles but not in normal placentas. c-myc expression was very low in hydatidiform moles and normal placentas. Both oncogenes, however, had no direct correlation with the clinical course of the molar pregnancies. CONCLUSION: The difference in c-fms expression between hydatidiform moles and normal placentas suggests that c-fms may have a role in the development of molar pregnancies.     

The significance of proliferating cell nuclear antigen in human trophobiastic disease: an immunohistochemical study

The expression of proliferating cell nuclear antigen (PCNA) in human trophobiastic disease was assessed immunohistochemically in tissue from 29 spontaneous abortions, 33 partial moles, 40 complete moles and 23 chorio carcinomas using the monoclonal antibody PC ID. PCNA immunoreactivity occurred predominantly in the cytotrophoblasts in each of the four types of tissues. Quantitative analysis showed that the choriocarcinoma group gave a statistically significant higher PCNA index than the other three. There was no significant difference between the groups of spontaneous abortion, partial or complete mole. Sixteen of the 73 patients with partial and complete moles developed persistent gestational trophobiastic disease and there was no significant difference between the patients requiring chemotherapy and those who did not. We conclude that choriocarcinoma has a significantly higher PCNA proliferative index whilst hydatidiform moles cannot be distinguished from abortions by such analysis. The PCNA index does not appear to be useful in predicting the progression of molar pregnancies to persistent trophobiastic diseases.     

Immunohistochemical expression of cell cycle proteins E2F-1, Cdk-2, Cyclin E, p27(kip1), and Ki-67 in normal placenta and gestational trophoblastic disease.

The role of cell cycle protein expression in gestational trophoblastic disease is poorly understood. In this study we investigated the immunostaining patterns of G(1) restriction point and G(1)-S regulatory proteins E2F-1, Cdk2, cyclin E, p27(kip1), and the proliferation marker Ki-67 on routinely processed sections of 29 hydatidiform moles (10 partial moles and 19 complete moles, including 9 persistent moles), 7 choriocarcinomas, and 7 normal placentas. Ki-67 trophoblast staining decreased with increasing gestational age of the placenta, and showed maximal expression in gestational trophoblastic disease. Cyclin-dependent kinase activity, as reflected by Cdk2 expression patterns, also decreased with placental maturation. E2F-1 was uniquely expressed by trophoblasts of moles and choriocarcinoma. Cyclin E was maximally expressed by complete moles and choriocarcinomas, and showed an inverse relationship with the cyclin-dependent kinase inhibitor p27(kip1). Abnormal trophoblastic proliferations may be mediated through interactions of Cdk-2, E2F-1, cyclin E, and p27(kip1). Overexpression of cyclin E was associated with more aggressive forms of gestational trophoblastic disease. However, we did not find distinguishing features between complete moles that spontaneously resolved after evacuation and persistent moles that required chemotherapy. The different expression patterns of cyclin E and E2F-1 in partial and complete moles may be useful in distinguishing these two entities. Furthermore, loss of p27(kip1) in malignant trophoblast may represent a necessary step in the development of choriocarcinoma.     

Expression of proliferating cell nuclear antigen,Ki-67 antigen,estrogen receptor protein,and tumor suppressor p53 gene in cytologic samples of breast cancer: An immunochemical study with clinical,pathobiological, and histologic correlations

Sixty-six unselected breast cancers were analyzed in cytologic smears and histologic sections for the expression of Ki-67, proliferating cell nuclear antigen (PCNA). estrogen receptor protein (ERP), and p53 protein using a standard immunochemical method. The results, expressed as both positive cases and labelling index (LI), were compared with clinical and pathobiological variables. Ki-67 and PCNA immunostaining was seen in all cases, whereas ERP was detectable in 46/63 cases and p53 protein in 20/66 cases. The expression of these markers was generally lower in cytology than in histology, though the differences were not statistically significant. PCNA-LI and Ki-67-LI were closely correlated (P < 0.001), the mean PCNA:Ki-67 ratio being 0.92 ± 0.57. Occasional discrepancies, however, were found. PCNA and Ki-67 expression was associated with an increase in histologic grade and a decrease in ERP content of tumors, whereas p53 was statistically associated with no clinical or pathobiological variables. The data suggest that proliferative activity and oncogene overexpression may be reliably evaluated in breast cancer by FNA cytology, though PCNA is not a suitable indicator for cell proliferation. The results do not resolve the issue as to whether immunostaining for p53 protein constitutes a dedifferentiation product of the tumor, or is a fundamental aspect of the malignant progression. Survival studies in a larger series of tumors are thus needed to elucidate this point. Diagn Cytopathol 1994; 11:131–140. © 1994 Wiley-Liss, Inc.     

Immunogold labelling of PCNA and Ki-67 antigen at the ultrastructural level in laryngeal squamous cell carcinoma and its correlation with lymph node metastasis and histological grade

Streptavidin-gold was used for the immunolocalization of PCNA and Ki-67 antigen at the ultrastructural level with a postembedding technique in biopsies of 15 patients with laryngeal squamous cell carcinoma. Positive immunoelectron staining was obtained in 9 cases for PCNA (60%) and in 8 cases for Ki-67 (53%). PCNA was predominantly found in heterochromatin of the nucleus of laryngeal carcinoma cells in a granular pattern. Positivity for PCNA was not found in nucleoli. In 4 cases, positive staining was observed both in nucleus and cytoplasm. In the cytoplasm, it was found to be present on the endoplasmic reticulum and on ribosomes throughout the cytoplasm. Ki-67 antigen was localized in the nucleus where it was associated with heterochromatin and euchromatin. It was also observed in nucleoli in all cases. Cytoplasmic localization of Ki-67 antigen was similar to that of PCNA. All 8 cases that were positive for Ki-67 were also positive for PCNA. Control incubations did not result in labelling with steptavidin-gold particles for both antigens. A significant correlation between PCNA and Ki-67 expression in association with pathological characteristics such as nodal status and histological grade was not found. Our data indicate that Ki-67 antigen staining correlates with PCNA labelling, whereas a relationship between proliferation markers and tumour progression was not found.