胃肠道间质瘤中p16、p27、Ki-67表达

目的探讨胃肠道间质瘤中p16、p27和Ki67表达与临床预后的关系。方法根据核分裂象的多少、肿瘤体积的大小及有无浸润等将胃肠道间质瘤划分为良性、交界性和恶性,并运用免疫组化SP方法检测p16、p27和Ki67在胃肠道间质瘤中的表达,并统计分析其良性、交界性、恶性和复发死亡病例中的表达差异。结果p16、p27和Ki67的阳性表达率分别为48%、26%和24%。p16在良、恶性中的表达无明显差异,但在良性和交界性中的表达与复发和转移相关;p27低标记指数和Ki67高标记指数与复发和转移相关。结论p16、p27和Ki67在胃肠道间质瘤中的表达对判断预后有价值。     

细胞周期蛋白D1、Ki-67和bcl-2的表达与CD117阳性的胃肠道间质瘤生物学行为的关系

目的 检测细胞周期蛋白D1（cyclin D1）、Ki-67和bcl-2在胃肠道间质瘤（GIST）中的表达,探讨它们在GIST发生、发展中的作用及临床病理意义。方法 59例手术切除GIST标本进行CD117、CD34、平滑肌肌动蛋白（SMA）、结蛋白、S-100、cyclin D1、bcl-2和Ki-67免疫组织化学染色,同时进行病理形态学观察包括形态学类型、肿瘤大小、坏死和核分裂象。所有病例随访2～9年。所有数据进行单因素、多因素和相关分析。结果 随访40例患者一直健在,15例患者死于GIST,4例患者死于其他原因。统计学分析显示肿瘤直径〉5cm、有坏死、核分裂象在每50个高倍视野〉5个、Ki-67增殖指数（LI）〉5％、cyclin D1和bcl-2免疫组织化学染色强阳性都可以作GIST患者手术后的预测指标,且具有统计学意义;核分裂象和Ki-67增殖指数是独立的预测指标;Ki-67 LI≥5％和核分裂象≥5／50 HPF呈正相关（r=0．532,P〈0．01）;cyclin D1与bcl-2强阳性表达呈正相关（r=0.273,P〈0．05）。结论 肿瘤大小、坏死、核分裂象、cyclin D1、Ki-67增殖指数和bcl-2可作为GIST患者临床预测指标;核分裂象和Ki-67增殖指数可作为独立的预测指标;cyclinD1与bcl-2呈明显相关性,Ki-67免疫组织化学染色可以代替核分裂象作为一项很有用的预测指标。     

Immunolocalization of cell cycle proteins (p57, p27, cyclin D3, PCNA and Ki67) in intrauterine growth retardation (IUGR) and normal human term placentas

Placental development involves a series of events that depend on the coordinated action of proliferation, differentiation and invasion of trophoblasts. Studies on cell cycle related proteins controlling these events are fairly limited. It is still not fully determined how placental tissue proliferation is affected by intrauterine growth retardation (IUGR). Information on cell cycle related proteins that control these events is limited and how they are affected in IUGR is not fully understood. The aim of this study was to understand the role of cell cycle regulators in IUGR placentas and to determine the spatio-temporal immunolocalization of these cell cycle regulators in human IUGR and normal term placentas. Placental samples were stained immunohistochemically with PCNA, Ki67, cyclin D3, p27 and p57 antibodies and were examined by light microscopy. In all regions of IUGR placentas, PCNA, Ki67 and cyclin D3 staining intensities were statistically significantly decreased compared to normal controls. p27 staining intensity of the IUGR group was statistically significantly increased in villous parts and chorionic plates in comparison with the normal term placentas. Moreover, p57 staining intensity was statistically significantly increased in all parts of the IUGR group compared to controls. The observed placental abnormalities in IUGR placentas may be associated with arrest mechanisms affecting cell proliferation and cell cycle alterations in IUGR.     

Intratumoral heterogeneous expression of p53 correlates with p53 mutation,Ki-67, and cyclin A expression in endometrioid-type endometrial adenocarcinomas

To further elucidate the significance of p53 mutation in endometrial carcinoma, we investigated it in endometrioid-type endometrial carcinomas showing intratumoral heterogeneous p53 expression. In addition, we also examined the correlation of p53 mutation and cyclin A expression, because we previously reported a topological correlation between the expression of p53 and cyclin A. The p53 mutation in exons 5–8 in 54 cases of endometrial carcinoma showing immunohistochemical expression of p53 was examined using microdissected tissue DNAs. Of the 54 p53-positive endometrial carcinomas, 23 (43%) had p53 mutation with a tendency in histologically higher grade tumors. Ten of the 54 showed a heterogeneous p53 expression, and in 9 of the 10 cases, p53 mutation was present only in p53-positive sites, which were often found in histologically less differentiated areas with elevated Ki-67 in the same tumor. Cyclin A expression was topologically observed in p53-positive areas; however, it was noted in both tumors with (12/23, 52%) and without (18/31, 58%) p53 mutation. These results suggest that p53 mutation is a late event and plays an important role in the acquisition of malignant potentials in endometrioid-type endometrial adenocarcinomas. Unexpectedly, accumulation of the p53 protein itself may be important in cyclin A overexpression.     

Bottom-up cell proliferation with cyclin A and p27Kip1 expression in ulcerative colitis-associated dysplasia

To analyze the cell kinetics of ulcerative colitis (UC)-associated dysplasia, cyclin A, cyclin D1, cyclin E, cdk2, cdk4, p21(Waf1), and p27(Kip1) were immunohistochemically examined, in comparison with sporadic tubular adenomas. Immunohistochemical labeling indices for each marker in formalin-fixed paraffin-embedded tissue sections were assessed in a total of 23 low-grade dysplasias, 27 high-grade dysplasias, and 14 invasive adenocarcinomas associated with UC. For comparison, 21 sporadic tubular adenomas with low-grade dysplasia, 33 with high-grade dysplasia, and 21 invasive adenocarcinomas were also examined. In UC-associated dysplasias, cyclin A and p27(Kip1) were located in the lower parts of the crypts and p21(Waf1) in the upper regions. In tubular adenomas, cyclin A, cdk4, p27(Kip1), and p21(Waf1) were all expressed in the upper parts of the crypts. The expression levels of cyclin D1, cyclin E, and cdk2 were low. The cell proliferation zone in UC-associated dysplasia is located towards the bases of the crypts with the strong expression of cyclin A and p27(Kip1), in contrast to tubular adenomas, which have their cell proliferation zone in the upper parts of neoplastic crypts. It is considered that tumorigenesis with UC-associated dysplasia is of the bottom-up type, related to altered expression of cyclin A and p27(Kip1).     

Cyclin D3与Ki67在非霍奇金淋巴瘤中的表达及其意义

目的：探讨cyclinD3和Ki67在我国非霍奇金淋巴瘤(non-Hodgidn’s lymphoma，NHL）中的表达及其意义。方法：采用免疫组织化学方法检测114例IXTIL和20例反应性增生淋巴结中cyclinD3及Ki67的表达情况。结果：cyclin D3在反应性增生淋巴结(不包括生发中心)中的阳性率明显低于NHL。随着肿瘤侵袭性的增加，cyclinD3表达水平升高。Ki67在反应性增生淋巴结和NHL中的表达情况与cyclin D3一致。NHL中cyclinD3的阳性率与Ki67的表达水平呈明显正相关。结论：cyclinD3和Ki67的表达与NHL的细胞增殖活性和恶性程度密切相关，提示cyclin D3在淋巴瘤的恶性增殖过程中发挥重要作用，为淋巴瘤的诊治提供新的依据和靶点。     

Cyclin D1和p16、p27在脑胶质瘤中的表达及其与PCNA的相关性

目的 :检测CyclinD1 和p16、p2 7以及PCNA在脑胶质瘤中的表达状况 ,以探讨不同病理类型脑胶质瘤中各自的表达及其相关性。方法 :应用免疫组化S P法 ,检测 12例正常脑组织、5 8例脑胶质瘤组织中CyclinD1 、p16、p2 7及PCNA表达及其特征。结果 :CyclinD1 在由低度恶性胶质瘤向高度恶性胶质瘤转化中阳性表达逐渐增强 (χ2 检验 ,P <0 0 0 5 ,χ2 =5 1 6 7) ;而p16、p2 7阳性表达却是随着胶质瘤恶性程度的升高而降低 (χ2 检验 ,P值均 <0 0 0 5 ,χ2 分别为 15 4 1和 12 81)。CyclinD1 与PCNA呈正相关 ,rs =0 74 5 ;p16和p2 7与PCNA呈负相关 ,rs分别为 - 0 5 6 6和 - 0 6 12。结论 :脑胶质瘤中CyclinD1的表达程度对胶质瘤的细胞增殖活性起促进作用 ,而p16、p2 7的表达则起抑制作用。     

Correlation of enhanced cell turnover with prognosis of gastrointestinal stromal tumors of the stomach: relevance of cellularity and p27kip1

The aim of the present study was to determine whether expression of molecules associated with cell cycle regulation and apoptosis might reflect tumor grade and patients' prognosis of gastrointestinal stromal tumor (GIST). Forty-nine cases of gastric GIST were divided into three grades; low, intermediate, and high risk. Ki-67, cyclin A, cyclin D1, cyclin E, p16(Ink4), p21(Waf1), p27(Kip1), cyclin-dependent kinase (cdk)2, cdk4 and single-strand DNA (ssDNA) were immunohistochemically stained and assessed. Ki-67, ssDNA, cyclin A and cdk2 had higher labeling indices (LI) in high-risk than in low-risk cases. Cyclin E expression was greater in the intermediate- than in the low-risk grade. On Kaplan-Meier analysis, tumor size, necrosis, cellularity, Ki-67, ssDNA, and cyclin A LI were significantly correlated with disease-free survival. Necrosis, cellularity, and Ki-67 LI were significant as prognostic factors on univariate, and Ki-67 LI on multivariate Cox hazard tests. Within the high-risk grade, high cellularity and low p27(Kip1) subgroups had the worst prognosis. The histological grade is related to cell turnover, assessed in terms of Ki-67, ssDNA, cyclin A, cyclin E, and cdk2 levels. Ki-67, ssDNA, and cyclin A are useful for prediction of prognosis, with cellularity and p27(Kip1) expression as further prognostic factors in high-risk cases.     

beta-catenin nuclear expression correlates with cyclin D1 overexpression in sporadic desmoid tumours

The immunohistochemical expression of beta-catenin, cyclin D1, Ki-67 and PCNA was Examined in 38 cases of sporadic extra-abdominal or abdominal-wall desmoid tumours without familial adenomatous polyposis (FAP), to evaluate the hypothesis that the accumulated beta-catenin within the nuclei could affect the regulation of the cyclin D1 gene. There was a statistically significant correlation between beta-catenin accumulation and cyclin D1 overexpression (p=0.029). Each group with beta-catenin accumulation or cyclin D1 overexpression showed a higher PCNA-LI than those without, the difference being statistically significant (p=0.007, p=0.004, respectively). Differential PCR was also performed to detect amplification of the cyclin D1 gene and mutational analysis was undertaken for exon 3 of the beta-catenin gene. Amplification of the cyclin D1 gene was observed in 13 out of 22 cases (59.1%). There were nine-point mutations in 7 out of 18 cases (38.9%). The distribution of beta-catenin mutation fell within a wide range, from codon 21 to codon 67. In conclusion, beta-catenin nuclear expression correlated with cyclin D1 overexpression in sporadic desmoid tumours, which could be an in vivo model system for the APC-beta-catenin-Tcf pathway. In addition, beta-catenin mutations in desmoid tumours occurred at an unusually wide range of sites within the gene.     

肾癌中cyclinD1和p27kip1的表达及其意义

目的探讨cyc lin D1、p27k ip1在普通型肾细胞癌(renal cell carc inom a,RCC)发生、发展中的作用。方法用半定量RT-PCR方法检测25例普通型RCC和10例肿瘤远端的正常肾组织中cyc lin D1的mRNA含量,用免疫组化方法检测76例普通型RCC中cyc lin D1和p27k ip1蛋白的表达,并对cyc lin D1、p27k ip1蛋白表达与临床病理参数的关系进行分析。结果普通型RCC中cyc lin D1的mRNA含量0.488±0.399,高于正常对照组0.089±0.066(P<0.01)。cyc lin D1的表达与肿瘤体积大小有关,体积大者cyc lin D1高表达(P<0.05)。普通型RCC中p27k ip1表达低于正常对照组,随着p27k ip1表达的降低,肿瘤的细胞核Fu-hrm an分级、TNM分期增高。结论cyc lin D1高表达和p27k ip1的低表达与普通型RCC的发生有关;p27k ip1的低表达可能促进肿瘤的演进,p27k ip1的表达可作为评价普通型RCC预后的参考指标。     

Immunohistochemistry of cyclin D3 in pulmonary carcinomas

Cyclin D3, a cell cycle regulator, is encoded in the 6q21 chromosome region. Abnormalities of this gene and its protein product have not been found in normal tissues or in malignancies from human subjects. The expression of cyclin D3 was studied immunohistochemically in archival formalin-fixed, paraffin-embedded specimens from normal organs obtained from three autopsy cases and 237 human primary pulmonary carcinomas. In normal organs, nuclear positivity for cyclin D3 was observed in reactive type-2 pneumocytes, islets of Langerhans, lymphocytes from lymph nodes, superficial cells of transitional epithelium, epithelium of oesophagus, stomach, small intestine and gallbladder, endothelium, smooth muscles, and brain. Proliferating cells such as lymphocytes in the germinal centres and non-proliferating cells such as neurons both demonstrated cyclin D3 immunoreactivity. Cyclin D3 showed obvious nuclear immunoreactivity in 168 pulmonary carcinomas (71%). The proportion of tumour cells that were cyclin D3-positive ranged from 1% to 73% (median, 16%). There was no relationship between cyclin D3 immunoreactivity and histological typing, tumour differentiation, or pathological TNM staging. In pulmonary carcinomas, distinct expression of the cyclin D3 protein is unlikely to be implicated in tumorigenesis, because of its expression in only a small fraction of cancer cells. It may relate to cancer progression. The distribution of cyclin D3 reactivity in the normal tissues suggests that cyclin D3 affects other processes than cell cycle regulation in a lineage-specific manner.     

Differential expression of p16/p21/p27 and cyclin D1/D3, and their relationships to cell proliferation, apoptosis, and tumour progression in invasive ductal carcinoma of the breast

In order to understand the intricate relationship of cell proliferation and apoptosis in tumour development, proliferation markers (Ki-67 and c-myc), apoptosis, cell-cycle inducers cyclin D1 and D3, and cell-cycle inhibitors p16(INK4), p21(CIP1), and p27(KIP1) were evaluated in ductal breast carcinoma. The heterogeneous nature of breast tumours provides a system by which the changes in cell-cycle genes can be explored under a wide range of proliferation and apoptotic indices. To address the above issues, immunohistochemical studies were conducted in 40 pairs of tumours and adjacent normal ductal tissues. The TUNEL method was used to identify apoptotic cells. Except for p27/KIP1, the proliferation (Ki-67, c-myc) and the apoptotic indexes together with levels of p16/INK4a, p21/CIP1, cyclin D1, and cyclin D3, were clearly elevated among tumour tissues, while absent in the adjacent normal tissues. Spearman correlation analysis indicated strong associations among apoptotic index, Ki-67, c-myc, and tumour grade. In addition, p21/CIP1 and cyclin D3 were positively correlated, while p16/INK4a, p27/KIP1, and cyclin D1 were negatively correlated with tumour grade. There was clear decoupling between p21 and p27, as well as decoupling between cyclin D1 and cyclin D3, in terms of their relationship to cell proliferation and apoptosis, indicating differential roles in tumour progression.     

Expression of cyclins,p53, and Ki-67 in cervical squamous cell carcinomas: overexpression of cyclin A is a poor prognostic factor in stage Ib and II disease

We previously reported the overexpression of cyclins in uterine cervical carcinoma; however, their clinicopathological significance remained undetermined. In the present study, we examined the immunohistochemical expression of cyclins (D1, E, A, B1), p53 and Ki-67 in squamous cell carcinoma (stage Ib+II; 80 cases, stage III+IV; 23 cases). Correlations between the expression of cyclins and clinicopathological parameters and patient survival were statistically evaluated. The results indicated that in the normal squamous epithelium, the expression of cyclins and Ki-67 was sporadically observed in the parabasal layer. Of the 103 cervical carcinomas, overexpression of cyclins D1, E, A, B1 and p53 was observed in 13 (13%), 23 (22%), 25 (24%), 18 (18%) and 23 (22%) cases, respectively, with a slight predominance in advanced stage tumors. The expression of cyclin D1, E, A and p53 significantly correlated with that of Ki-67 (Spearmans rank correlation). Univariate and multivariate analyses revealed that lymph node metastasis and cyclin A overexpression were independent prognostic factors for unfavorable outcomes in stage Ib+II patients. These findings suggest that the overexpression of various cyclins is involved in the acquisition of the vigorous growth potential of cervical carcinoma cells, and that cyclin A is an independent prognosticator of cervical carcinoma in early stages.     

Correlation of cyclin D1 and E1 expression with bladder cancer presence, invasion, progression, and metastasis

The objective of this study was to determine the correlation of the expression of cyclin D1 and E1 with the expression of commonly altered cell cycle regulators and bladder cancer presence, staging, and clinical outcomes. We performed immunohistochemical staining for cyclin D1, cyclin E1, p53, p21, p27, and retinoblastoma protein (pRB) on serial cuts from normal urothelium from 9 controls, radical cystectomy specimens from 226 consecutive patients with advanced transitional cell carcinoma, and lymph nodes with metastasis from 50 of the 226 cystectomy patients. Cyclin D1 and E1 immunoreactivity were considered low when samples demonstrated less than 10% and 30% nuclear reactivity, respectively. Normal bladder urothelium from all 9 control patients showed uniformly intense expression of cyclin D1 and E1. Cyclin D1 expression was low in 99 (43.8%) of 226 cystectomy specimens and 25 (50.0%) of 50 metastatic lymph node specimens. Cyclin D1 immunoreactivity was not associated with any pathologic characteristics or clinical outcomes. Cyclin E1 expression was low in 125 (55.3%) of 226 cystectomy specimens and 22 (44.0%) of 50 metastatic lymph node specimens. Low cyclin E1 expression was significantly associated with advanced pathologic stage, lymphovascular invasion, and lymph node metastases. In multivariate analyses, low cyclin E1 expression was significantly associated with bladder cancer-specific mortality (P = .048), but not disease recurrence (P = .056). Low cyclin E1 expression was significantly associated with altered expression of pRB, p27, and cyclin D1. Low cyclin D1 expression was significantly associated with altered expression of pRB, p21, and cyclin E1. Cyclin E1 expression stratifies patients with bladder transitional cell carcinoma into those with more "indolent" behavior and those with features of biologically and clinically aggressive disease.     

p16、Rb和cyclin D1蛋白在横纹肌肉瘤中的表达及其意义

目的：探讨细胞周期相关蛋白表达异常与横纹肌肉瘤（RMS）的关系。方法：应用S－P免疫组化方法观察p16,Rb和cyclinD1蛋白在RMS中的表达状态。结果：p16,Rb和cyclinD1蛋白表达阳性率分别为55．3％,61．7％和51．1％,在胚胎性横纹肌肉瘤（ERMS）,p16和Rb蛋白表达阳性率为75．0％（21／28）和67．9％（19／28）,明显高于在腺泡状横纹肌肉瘤（ARMS）中的表达（P＜0．05）,p16蛋白阳性率在I,Ⅱ级横纹肌肉瘤分别为75．0％和73．3％,高于Ⅲ级横纹肌肉瘤（45．0％）;p16蛋白阴性及cyclinD1蛋白过表达组,局部浸润,复发或转移发生率高于p16蛋白阳性及cyclinD1蛋白阴性组;11／47例（23．4％）出现两种以上蛋白表达异常。结论：P16,Rb和cyclinD1蛋白异常可能与部分横纹肌肉瘤发生发展有关,且横纹肌肉瘤的发生可能涉及两种以上基因异常。     

Elevated levels of p27, p21 and cyclin D1 correlate with positive oestrogen and progesterone receptor status in node-negative breast carcinoma patients

The search for better prognostic indicators and new treatment modalities in node-negative breast carcinoma patients is important. The aim of this study was to determine the immunohistochemical expression of central cell regulator proteins in relation to hormone receptor status, tumour-cell differentiation and prognosis. We investigated the immunoreactivity of p27, p21, cdk4, cyclin D1 and p53 in 77 node-negative breast carcinomas, with long-term follow-up (mean 163 months; range 20−227). Nuclear staining for p27 was seen in 87% of the carcinomas, for cdk4 in 92%, for p21 in 68%, for cyclin D1 in 58% and for p53 in 18%. Oestrogen receptor (ER) and progesterone receptor (PgR) nuclear staining was seen in 69% and 65% of the tumours, respectively. No correlation between the levels of p21 and p53 was observed. P21 overexpression was, however, associated with positive ER status. Elevated levels of p27 and cyclin D1 correlated with positive hormone status (both ER and PgR). We did find a significant correlation between p27 and cyclin D1 and histological grade of the tumours, with extensive positive immunostaining of p27 and cyclin D1 in well-differentiated carcinomas. The only significant prognostic factor in our series was histological grading. Ten-year relapse-free survival was significantly prolonged in patients with histological grade I tumours versus histological grade II and III tumours. Our results suggest that the expression of p27 and cyclin D1 is closely linked to hormone receptor status in breast carcinomas and to tumour differentiation, a finding that may be of importance in the treatment of hormone-dependent tumours. Received: 26 March 1998 / Accepted: 29 April 1999     

结直肠癌中cyclin D1和p27蛋白的表达及其意义

目的　研究cyclinD1和p2 7蛋白在结直肠癌发生、发展中的作用及其与结直肠癌临床病理特征关系。 方法　收集5 8例手术切除的结直肠癌标本 ,同时取距癌灶 >5cm的正常组织 ,应用免疫组化S P法检测癌组织及正常组织中cyclinD1和p2 7蛋白的表达。结果　cyclinD1蛋白在结直肠癌的表达阳性率为 5 5 17%,正常组织无表达 (P <0 0 1) ;cyclinD1蛋白的表达阳性率在 6 0岁以上年龄组高于 6 0岁以下年龄组 (P <0 0 5 ) ;cyclinD1蛋白的表达与肿瘤组织分化程度负相关 (P <0 0 1)。p2 7蛋白在结直肠癌的表达阳性率为 5 5 17%,在结直肠正常组织的表达阳性率为 96 5 5 %(P <0 0 1) ;p2 7蛋白的表达与肿瘤组织分化程度负相关 (P <0 0 1)。cyclinD1和p2 7蛋白在结直肠癌的表达呈正相关 (r =0 5 82P <0 0 1)。 结论　cyclinD1蛋白过表达与 p2 7蛋白失活可加速细胞周期转化 ,促进结直肠癌的发生 ,cyclinD1和 p2 7蛋白的检测可作为评价结直肠癌恶性程度和判断预后的重要指标。     

Cyclin D1, p16INK4A and p27Kip1 in pancreatic adenocarcinoma: assessing prognostic implications through quantitative image analysis

The prognostic significance of cyclin D1, p16^INK4A and p27^Kip1 expression has been documented in several human malignancies; however, their prognostic potential in pancreatic adenocarcinoma is still unclear. This study aimed to assess the correlation of the aforementioned molecules with clinicopathological parameters and prognosis. Sixty patients with pancreatic ductal adenocarcinoma underwent surgical resection at a single institution; immunohistochemical staining of the studied markers was quantified by Ιmage analysis system. Cyclin D1 overexpression was positively associated with grade, neural infiltration and vascular invasion, whereas p27 positively correlated with age. Higher cyclin D1 expression indicated poorer survival (adjusted HR = 9.75, 95%CI: 1.48–64.31, p = 0.018, increment: one unit in H‐score), whereas a marginal trend toward an association between p16 positivity and improved survival was observed (adjusted HR = 0.58, 95%CI: 0.32–1.05, p = 0.072 regarding positive vs negative cases). No significant association with overall survival was noted regarding p27. In conclusion, cyclin D1 overexpression and possibly p16 loss of expression in pancreatic adenocarcinoma seem to be adverse prognostic factors, whereas p27 expression did not seem to possess such prognostic properties. Further validation of the present findings in studies encompassing larger samples seems to be needed.     

Cyclin D3 immunoreactivity in gastrointestinal stromal tumors is independent of cyclin D3 gene amplification and is associated with nuclear p27 accumulation.

An abnormal expression of cyclin D3, a key regulator of the cell cycle, has been documented in a variety of human malignancies, and the cyclin D3 gene, mapping to 6p21, may be deregulated in human tumors as a result of the t(6;14)(p21.1;q32.3) translocation or gene amplification. In the current study, we for the first time investigated by immunohistochemistry and fluorescence in situ hybridization (FISH) the prevalence of cyclin D3 abnormalities in gastrointestinal stromal tumors (GISTs), comparing the results with traditional pathological characteristics, p27 immunoreactivity (IR), and Ki-67 labeling index (LI). All the tumors showed nuclear cyclin D3 IR, with a percentage of immunostained neoplastic cells ranging from 10 to 95% (mean, 67.3 +/- 22.9%). In 4 (40%) of the 10 cases analyzed by FISH, cyclin D3 extrasignals were detected. Cohybridization with probes specific for the centromeric region and the long arm of chromosome 6 indicated trisomy in one case, whereas in the remaining three cases the pattern was highly suggestive for the occurrence of an isochromosome 6p. There was no association between the cyclin D3 gene copy number and IR for the encoded protein. Cyclin D3 IR was positively associated with p27 IR (P =.004) but not with Ki-67 LI or tumor malignant potential. On the contrary, p27 IR was inversely associated with Ki-67 LI (P =.004) and was more prevalent in tumors of low or intermediate malignant potential, though at a borderline level of statistical significance (P =.066) only. These data suggest that cyclin D3 expression in GISTs is independent of gene amplification and that this protein may be involved in the pathogenesis of GISTs by counteracting the inhibitory activities of p27.