Cyclin D1 gene amplification and overexpression are present in ductal carcinoma in situ of the breast

Cyclin D1 (CCND1) amplification is found in 10–15 per cent of invasive breast carcinomas, but it is not well established whether this gene alteration also occurs in the precursor of invasive breast carcinoma, ductal carcinoma in situ (DCIS). By Southern blot analysis, cyclin D1 gene amplification was detected in 10 per cent (3/32) of DCIS cases. In addition, 15 cases of DCIS were analysed using bright field in situ hybridization (BRISH), of which 11 had already been analysed by Southern blotting. One additional case with gene amplification was found by BRISH. The use of BRISH for the detection of gene amplification is shown to be a novel and reliable in situ method on paraffin-embedded tissue sections. By immunohistochemistry, 147 cases of DCIS were analysed for the expression of cyclin D1. Cyclin D1 overexpression was found in 9 per cent of well-differentiated, 29 per cent of intermediately differentiated, and 19 per cent of poorly differentiated DCIS. No statistically significant association was found between cyclin D1 overexpression and the differentiation grade of DCIS, although 90 per cent of the cases that show overexpression are classified as intermediately and poorly differentiated. An association was found between cyclin D1 overexpression and oestrogen receptor positivity. Cyclin D1 overexpression was found in all four cases with cyclin D1 gene amplification, but was also found in 30 per cent (8/27) of cases without detectable gene amplification. It is concluded that cyclin D1 gene amplification is an early event in the development of breast carcinoma and occurs in poorly differentiated DCIS. Cyclin D1 protein overexpression is also present in tumours without cyclin D1 gene amplification and is seen predominantly in DCIS of intermediately and poorly differentiated histological type and oestrogen receptor positivity. Copyright © 1999 John Wiley & Sons, Ltd.     

Cyclin D1 overexpression lacks prognostic significance in superficial urinary bladder cancer

The biological behaviour of urinary bladder neoplasms cannot be adequately predicted by histological criteria alone. Cyclin D1 is a cell-cycle regulating protein known to be overexpressed in a proportion of bladder carcinomas. To evaluate the prognostic significance of cyclin D1 expression and its relationship with tumour phenotype, 392 bladder carcinomas were analysed by immunohistochemistry. Clinical follow-up information was available in 337 patients with superficial bladder tumours (stages pTa/pT1). Cyclin D1 positivity was seen in 176 of 392 carcinomas. Cyclin D1 overexpression was strongly linked to papillary tumour growth, low stage, and low histological grade (p<0·005 each). Multivariate analysis showed that papillary tumour growth was the only parameter which was independently linked to cyclin D1 positivity. There was no significant difference in proliferative activity (Ki67 labelling index) between cyclin D1-negative and -positive tumours. Cyclin D1 positivity was not linked to the risk of recurrence or tumour progression, either in pTa or in pT1 carcinomas. It is concluded that cyclin D1 positivity distinguishes a large subgroup of papillary bladder tumours, but there is no evidence of prognostic significance for increased cyclin D1 expression. Copyright © 1999 John Wiley & Sons, Ltd.     

Cyclin D1 in invasive breast carcinoma: favourable prognostic significance in unselected patients and within subgroups with an aggressive phenotype

Aims: To study the clinicopathological and prognostic value of cyclin D1 overexpression in patients with breast carcinoma. Methods and results: Immunohistochemistry was performed on paraffin‐embedded tissue specimens from 290 invasive breast carcinomas to detect the proteins cyclin D1, oestrogen receptor (ER), progesterone receptor (PR), p53, c‐erbB2, and topoisomerase IIα (topoIIα). Cyclin D1 staining was quantified using a computerized image analysis method. Cyclin D1 overexpression characterized smaller, ER‐positive and PR‐positive tumours (P = 0.017, P < 0.0001, and P < 0.0001, respectively), of a lower histological and nuclear grade (P = 0.011 and P < 0.0001, respectively), and with reduced expression of topoIIα (P = 0.001) and p53 (P < 0.001). Cyclin D1 was found to have an independent favourable impact on the overall survival of both the unselected cohort of patients (P = 0.011) and of patients with ER‐negative and lymph node‐positive tumours (P = 0.034 and P = 0.015, respectively). In triple‐negative tumours, cyclin D1 overexpression was found to have independent favourable impacts on both overall and relapse‐free survival (P = 0.002 for both). Conclusions: This is the first immunohistochemical study to dissociate the advantageous prognostic effect of cyclin D1 overexpression from its association with ER expression, and to provide evidence that cyclin D1 overexpression may be a marker of prolonged survival in patient subgroups with aggressive phenotypes.     

Cyclin D3 expression in primary Ta/T1 bladder cancer

Cyclin D3 deregulation has recently been reported in bladder cancer but its prognostic significance remains uncertain. A cohort of 159 patients with stage Ta or T1 primary bladder tumours was investigated to determine the significance of cyclin D3 expression in association with other G1-S phase regulators of the cell cycle (p53, p21Waf1, p27kip1, cyclin D1), including tumour proliferation (ki67-MIB1); its association with conventional clinicopathological parameters; and the relationship between cyclin D3 and loss of heterozygosity (LOH) at the 9p21 (p16INK4a locus) chromosome region. The end point of the study was progression-free survival. Cyclin D3, other G1-S phase regulators, and tumour proliferation were investigated by immunohistochemistry and measured by the grid-counting method. To validate the immunohistochemical expression, cyclin D3 was additionally assessed by western blotting in selected cases. LOH at the 9p21 chromosome region (marker D9S171) was assessed in 125 cases using an AB Prism 310 genetic analyser and a set of microsatellite fluorescence-labelled primers. Cyclin D3 overexpression was related to larger tumour size (>5 cm; p < 0.0001) and high tumour proliferation (>10%; p = 0.025). Mean cyclin D3 expression increased with 2004 WHO grading categories in stage Ta (p = 0.035, ANOVA) and stage T1 (p = 0.047, t test) tumours. Cyclin D3 was not related to other clinicopathological parameters, G1-S phase modulators, or 9p21 LOH. Cox's multivariate analysis selected cyclin D3 as an independent predictor of progression-free survival (p = 0.0012, relative risk (RR) = 5.2366) together with tumour size (p = 0.0115, RR = 4.4442) and cyclin D1 (p = 0.0065, RR = 3.3023). Cyclin D3 expression had the highest risk ratio. Our results suggest that expression of cyclin D3 is relevant to the progression-free survival of patients with Ta/T1 bladder carcinomas.     

Cyclin E gene (CCNE) amplification and hCDC4 mutations in endometrial carcinoma

Cyclin E overexpression occurs in a subset of endometrial carcinomas (ECs), but the molecular mechanisms underlying this alteration remain to be established. The present study has analysed amplification of the cyclin E gene (CCNE) and mutation in hCDC4, the gene coding for the F-box protein, which tags phosphorylated cyclin E for proteosomal degradation, to ascertain whether these alterations might be responsible for cyclin E overexpression in ECs. Cyclin E and p53 expression was studied by immunohistochemistry in eight atypical endometrial hyperplasias (AEHs), 51 endometrioid endometrial carcinomas (EECs), and 22 non-endometrioid endometrial carcinomas (NEECs). CCNE amplification was analysed by fluorescence in situ hybridization (FISH). Mutations in exons 2-11 of the hCDC4 gene were screened by PCR-SSCP-sequencing. Finally, the polymorphic marker D4S1610 was used to assess loss of heterozygosity (LOH) in the hCDC4 gene. Cyclin E overexpression was found in 26/81 (32%) cases and was associated with the histological type of the lesion, since it was not found in any AEHs but was present in 27% of EECs and 54.5% of NEECs (p=0.035). Cyclin E overexpression was associated with histological grade (p=0.011) and p53 immunostaining in EECs (p=0.033). CCNE amplification was found in 6 of 37 (16%) ECs examined. There was a significant association between CCNE amplification and the histological type of the lesion, since five (83%) of the six cases with amplification were NEECs (p=0.008). One EEC harboured an hCDC4 mutation: a CGA to CAA (Arg/Gln) change at codon 479. In addition, D4S1610 LOH was found in 7 of 23 (30%) informative cases analysed, but no correlation with cyclin E overexpression was found. However, the tumour with hCDC4 mutation also showed LOH. This is the first study demonstrating that cyclin E overexpression is associated with gene amplification in ECs, these alterations being more frequent in NEECs. Although hCDC4 exhibits a low mutation frequency in ECs overexpressing cyclin E, it seems to function as a tumour suppressor gene that is involved in endometrial carcinogenesis.     

Immunohistochemical expression of cyclin D1, E2F-1, and Ki-67 in benign and malignant thyroid lesions

Cyclin D1 and E2F-1 proteins are essential for the regulation of the G1/S transition through the cell cycle. Cyclin D1, a product of the bcl-1 gene, phosphorylates the retinoblastoma protein, releasing E2F-1, which in turn activates genes involved in DNA synthesis. Expression patterns of E2F-1 protein in thyroid proliferations have not been reported. This study used monoclonal antibodies for cyclin D1 and E2F-1 proteins to immunostain sections of normal thyroid, hyperplastic (cellular) nodules, follicular adenomas, follicular carcinomas, and papillary carcinomas. The proliferation rate was examined using an antibody specific for the Ki-67 antigen. Fluorescence in situ hybridization (FISH) methods and chromosome 11-specific probes were also employed to determine chromosome copy number and to assess for evidence of amplification at the 11q13 locus in papillary and follicular carcinomas with cyclin D1 overexpression. Concurrent overexpression of Ki-67, cyclin D1, and E2F-1 was found in the majority of benign and malignant thyroid lesions, compared with normal thyroid tissue. Cyclin D1 up-regulation was not due to extra copies of chromosome 11, or bcl-1 gene amplification. Malignant tumours showed the highest expression for all three markers, particularly papillary carcinomas. E2F-1 was detected at the same or slightly lower levels than cyclin D1. It was only found when cyclin D1 was overexpressed. Because cyclin D1 normally activates E2F-1, up-regulation of cyclin D1 may lead to E2F-1 overexpression in benign and malignant thyroid lesions.     

Cyclin D1 is frequently overexpressed in microsatellite unstable colorectal cancer, independent of CpG island methylator phenotype

Aims: Cyclin D1 and cyclin‐dependent kinases are commonly activated in colorectal cancer. Microsatellite instability (MSI) and CpG island methylator phenotype (CIMP) are important molecular classifiers in colorectal cancer. The aim was to clarify the relationship between cyclin D1, MSI and CIMP. Methods and results: Among 865 colorectal cancers with MSI and CIMP data, 246 tumours (28.4%) showed cyclin D1 overexpression by immunohistochemistry. DNA methylation in p14 and eight CIMP‐specific promoters (CACNA1G, CDKN2A (p16), CRABP1, IGF2, MLH1, NEUROG1, RUNX3 and SOCS1) was quantified by real‐time polymerase chain reaction (MethyLight). Both MSI‐high and CIMP‐high were associated with cyclin D1 overexpression (P < 0.0001). After tumours were stratified by MSI and CIMP status, the relationship between MSI‐high and cyclin D1 persisted (P ≤ 0.02), whereas the relationship between CIMP‐high and cyclin D1 did not. Cyclin D1 overexpression was correlated with BRAF mutation (P = 0.0001), p27 loss (P = 0.0007) and p16 loss (P = 0.02), and inversely with p53 expression (P = 0.0002) and p21 loss (P < 0.0001). After stratification by MSI status, the inverse relationship between cyclin D1 and p21 loss still persisted (P < 0.008). Conclusions: Cyclin D1 activation is associated with MSI and inversely with p21 loss in colorectal cancers. Cyclin D1 may play an important role in the development of MSI‐high tumours, independent of CIMP status.     

Molecular cytogenetic identification of cyclin D1 gene amplification in a renal pelvic tumor attributed to phenacetin abuse

Despite extensive epidemiologic evidence of phenacetin abuse as a risk factor for renal pelvic carcinomas, genetic alterations in the resultant tumors remain largely unclear. In this report, a phenacetin-associated renal pelvic carcinoma (histologically a transitional-cell carcinoma) from an 80-year-old female patient was evaluated by molecular cytogenetic methods. Fluorescence in situ hybridization was used to identify chromosome gains or losses for the cyclin D1, p53, Rb and c-myc genes and the ploidy of their respective chromosomes. Cyclin D1 gene amplification, but normal copy numbers of p53, Rb and c-myc, and normal ploidy of chromosomes 8, 11, 13 and 17 were observed. Expression of cyclin D1 protein was confirmed by immunohistochemistry. In the absence of p53, Rb or c-myc abnormalities, the results suggested that cyclin D1 gene amplification and its protein overexpression may be involved in the genesis of renal pelvic carcinomas associated with phenacetin abuse.     

Correlation of cyclin D1 and Rb gene expression with apoptosis in invasive breast cancer.

BACKGROUND: In vitro studies have shown that amplification and overexpression of the cyclin D1 gene can accelerate the progress of cells through the G1 phase. Therefore, cyclin D1 may have an apoptosis inhibiting effect. The retinoblastoma (Rb) gene was shown recently to be an important regulator of apoptosis. AIMS: To evaluate whether expression of the cyclin D1 and Rb genes correlated with apoptotic counts in a group of 97 invasive breast cancers. METHODS: Expression of the cyclin D1 and Rb genes was detected by standard immunnohistochemistry using paraffin wax embedded sections. Apoptotic cells were counted according to a strict protocol, in 10 fields of vision systematically spread over the most poorly differentiated area of the tumour, at a magnification of x630. Apoptotic cells counts were expressed as apoptotic cells/mm2. RESULTS: Cyclin D1 overexpression was found in 49% of cases. Loss of Rb expression was found in 44% of cases, and occurred particularly in poorly differentiated tumours. Cyclin D1 and Rb expression showed a positive correlation (p = 0.003). Apoptotic counts varied from 1 to 62/mm2. There were no significant correlations between cyclin D1 overexpression and apoptotic counts in the total group or in the retinoblastoma protein (pRb) positive tumours. Loss of Rb expression also showed no correlation with apoptotic counts. CONCLUSIONS: Cyclin D1 is frequently overexpressed in pRb positive tumours, but no evidence has been found for an anti-apoptotic effect of cyclin D1 overexpression or Rb expression in invasive breast cancer.     

Cyclin D1 overexpression in colorectal carcinoma in vivo is dependent on beta-catenin protein dysregulation,but not k-ras mutation

Cyclin D1 protein overexpression is commonly found in colorectal carcinomas (CRCs) and is associated with a poorer prognosis, but the mechanism underlying overexpression remains uncertain. Both dysregulation of beta-catenin protein expression and k-ras mutation have recently been shown to promote cyclin D1 expression in human in vitro and rodent in vivo studies. In this study, 53 sporadic CRCs were examined by immunohistochemistry for cyclin D1 and beta-catenin protein expression, and with PCR and direct DNA sequencing for k-ras gene status. The study also addressed whether cyclin Dl overexpression might associate with poorer prognosis because of a relationship with poorer response to 5-fluorouracil (5FU) chemotherapy. Cyclin D1 overexpression was demonstrated in 34/53 (64%) CRCs, was significantly associated with higher Dukes' stage, and was particularly prominent at the invasive edges of carcinomas. Furthermore, cyclin D1 overexpression was always and only seen in association with nuclear expression of beta-catenin. There were no significant associations between cyclin D1 overexpression and k-ras mutation or response to 5FU. Amongst 17 microsatellite unstable CRCs, a smaller proportion of tumours showed cyclin D1 overexpression (18%), but again cyclin D1 overexpression was only seen in cases showing nuclear beta-catenin expression. In conclusion, beta-catenin protein dysregulation, but not k-ras mutation, appears to be required for cyclin D1 overexpression in colorectal carcinoma in vivo.     

p21WAF1/Cip1 is associated with cyclin D1CCND1 expression and tubular differentiation but is independent of p53 overexpression in human breast carcinoma

p21^WAF1/Cip1 is an inhibitor of cdk/cyclin complexes, and thus regulates the cell cycle. p21 is also related to cell differentiation and is regulated by wild-type p53, although p53-independent regulatory pathways have been proposed. In order to analyse p21 expression as well as its relationship with p53 in human breast cancer, an immunohistochemical analysis was undertaken of 77 breast carcinomas, 16 of them with an in situ component; 30 adjacent normal tissue samples; and five non-neoplastic specimens. Forty-four infiltrating carcinomas (57 per cent) were p21-positive. Expression of p21 was also observed in pre-invasive lesions, whereas normal ducts were negative or focally and weakly positive. p21 expression was associated with high histological grade (II+III) (P-0·017) and poor tubule formation (P-0·002), and was significantly less frequent in lobular carcinomas (P-0·0001). p21 positivity also correlated with increased proliferation, but this seemed to be dependent on the histological grade. Twenty carcinomas (26 per cent) showed p53 overexpression, but this was not associated with p21 negativity, suggesting the existence of p53-independent mechanisms for p21 regulation in vivo. Cyclin D1^CCND1 expression was analysed in the same series and an association between p21 and cyclin D1 expression was found, since 23 of 26 cyclin D1-positive carcinomas were p21-positive (P<0·001 …). In conclusion, p21 is frequently overexpressed in breast carcinomas and this occurs in the early stages of neoplastic progression. This overexpression seems to be independent of p53 status and might be involved in cyclin D1 modulation. © 1998 John Wiley & Sons, Ltd.     

Absence of CCND1 gene amplification in breast tumours of BRCA1 mutation carriers.

BACKGROUND/AIMS: It was recently reported that significantly fewer breast tumours of BRCA1 mutation carriers overexpressed cyclin D1 and HER2 protein than tumours of age matched breast cancer cases unselected for family history. This study aimed to examine the genetic basis of this reduction by determining the frequency of tumours within this cohort showing DNA amplification of these genes. METHODS: Paraffin wax embedded sections of breast tumours from BRCA1 mutation carriers and age, grade, histological type, and tumour size matched non-familial controls that had previously been stained for cyclin D1 and HER2 protein overexpression were analysed for CCND1 and HER2 gene amplification using fluorescence in situ hybridisation. RESULTS: CCND1 amplification was detected in none of the 30 tumours of the BRCA1 mutation carriers and in 19 of 74 tumours of the matched controls. Of those samples previously determined to overexpress the HER2 protein, HER2 amplification was detected in one of three tumours from BRCA1 mutation carriers and in 13 of 17 tumours of the age matched non-familial cases. CONCLUSION: None of the tumours of BRCA1 mutation carriers showed CCND1 amplification and only one tumour showed HER2 amplification. In contrast, a large proportion of cyclin D1 and HER2 overexpression in tumours of non-familial breast cancer cases could be accounted for by amplification of these genes. These data suggest that breast tumorigenesis in BRCA1 mutation carriers occurs by a molecular mechanism distinct from that of age matched non-familial cases.     

Cyclin alterations in giant cell tumor of bone.

Cyclins play an important role in regulating the passage of dividing cells through critical checkpoints in the cell cycle. Because alterations of several cyclins, especially cyclin D1, have been implicated in the development of many human neoplasms, we examined 32 cases of giant cell tumor of long bones for cyclin D1 gene amplification and protein overexpression using differential polymerase chain reaction and immunohistochemistry, respectively. In addition, the expression of cyclin D3, cyclin B1, and the proliferation-associated antigen Ki-67 (MIB-1) was assessed immunohistochemically. Low-level cyclin D1 gene amplification was detected in 61% of giant cell tumor cases. All tumors showed cyclin D1, cyclin D3, cyclin B1, and Ki-67 (MIB-1) staining; however, the distribution was very characteristic. Cyclin D1 protein expression was seen predominantly in the nuclei of the giant cells, with occasional mononuclear cells staining. There was no correlation between cyclin D1 gene amplification and protein overexpression. Cyclin D3 staining showed a similar distribution, with 88% of cases showing protein overexpression. Cyclin D1 and/or D3 staining in the giant cells was never associated with staining for either cyclin B1 or Ki-67 (MIB-1), as the expression of the latter two proteins was restricted to the mononuclear cells. Cyclin B1 overexpression was seen in 44% of cases. Ki-67 (MIB-1) staining was present in all cases, and between 10 to 50% of the mononuclear cells were positive. These results suggest that alterations in cyclin D1 and/or D3 might play a role in the pathogenesis of giant cell tumor of bone.     

Lack of cyclin D1 overexpression in gastric carcinogenesis

AIMS: Cyclin D1 overexpression was examined in early gastric carcinomas and precursor lesions with the following aims; (1) to assess the chronology of cyclin D1 overexpression in various stages of gastric carcinogenesis, (2) to correlate cyclin D1 overexpression with the Lauren type, the grade of differentiation and the type of growth pattern of the tumours and (3) to correlate cyclin D1 overexpression with clinical parameters, in particular lymph node metastasis and overall prognosis. METHODS AND RESULTS: Forty-five paraffin-embedded gastrectomy specimens from early carcinomas were examined for the presence of various precursor lesions. The Lauren type, the grade of differentiation and the type of growth pattern were reassessed for all early carcinomas. Cyclin D1 overexpression was examined using the monoclonal antibody DCS-6. Cyclin D1 overexpression was absent from all precursor lesions. Ten early carcinomas (22%) were cyclin D1 positive without significant differences when stratified according to Lauren type, grade of differentiation, type of growth pattern or lymph node status. Univariate analysis failed to show a significant difference in 5-year surival rate between cyclin D1 positive and negative early carcinomas (90% vs. 94%). CONCLUSIONS: Cyclin D1 protein overexpression does not play a role in the progression from normal to neoplastic gastric mucosa and does not discriminate between intestinal and diffuse type early gastric carcinomas of Caucasian origin. Moreover, mechanisms other than cyclin D1 protein overexpression underlie the reported difference in biological behaviour of early gastric carcinomas with different types of growth pattern. Finally, although it appears that cyclin D1 does not have prognostic significance, studies on larger numbers, including advanced carcinomas, are warranted.     

p53 Alterations in thymic epithelial tumours

 The prognosis of thymic epithelial tumours depends on malignant behaviour that cannot always be predicted on histological grounds. This study aimed at identifying a molecular marker that would be useful in overcoming the drawbacks of histopathology. Forty-four thymic epithelial tumours were analysed for alterations of the tumour suppressor gene p53 using immunohistochemistry (antibodies D0-1 and CM-1) and PCR-based single-strand conformation polymorphism and DNA sequencing. Histological and clinical evaluation and also p53 analysis revealed three major tumour groups: non-organotypic thymic carcinomas with frequent p53 alterations (7/9) and occurrence of p53 gene mutations (2/9); malignant thymomas with frequent p53 alterations but without p53 gene mutations (11/18); and benign thymomas with rare p53 alterations and without p53 gene mutations (2/17). In non-organotypic thymic carcinomas p53 was detected with both antibodies. In contrast, thymomas lacked immunoreaction with D0-1 suggesting alteration of the antibody-binding site. Overall immunohistochemical results correlated with clinical stages (P < 0.01), pathohistology (P < 0.01), and survival times (P < 0.05). We consider immunohistochemical p53 detection to be a useful new prognostic factor for the evaluation of thymic epithelial tumours. Received: 5 September 1996 / Accepted: 17 February 1997     

Lowp53 protein expression in salivary gland tumours compared with lung carcinomas

Summary Fifty-one salivary gland tumours (23 pleomorphic adenomas, 5 Warthin's tumours, 12 mucoepidermoid carcinomas, 7 adenoid cystic carcinomas, 3 undifferentiated carcinomas and 1 acinic cell tumour) and 27 lung carcinomas (18 squamous cell carcinomas, 6 adenocarcinomas and 3 small cell carcinomas) were analysed immunohistochemically for the expression ofp53 nuclear phosphoprotein. Eight out of 51 (16%) salivary gland tumours werep53 positive. Three of these were benign and 5 malignant. All 3 benign salivary gland tumours were pleomorphic adenomas and expressed only occasional nuclear positivity with less than 1% of tumour cells positive. Of the 5p53-positive malignant tumours, 3 were mucoepidermoid carcinomas and 2 undifferentiated carcinomas. The malignant salivary gland tumours expressed more than 1% of positive nuclei in every case. Seventeen lung carcinomas werep53 positive (63%). Thirteen of these were squamous cell carcinomas, 3 were adenocarcinomas and 1 small cell lung carcinoma. The results show that mutations of thep53 gene may be infrequent in salivary gland tumours when compared with lung carcinomas. The relatively indolent course of some histological types of malignant salivary gland tumours could be associated with the preservation of the non-mutatedp53 gene in most of these tumours. The presence ofp53 positivity in some pleomorphic adenomas might, on one hand, suggest thatp53 gene alterations are also present in these tumours; on the other hand, the accumulation of thep53 protein in these tumours might also be due to some unknown mechanism, not necessarily related top53 gene mutation.     

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     

Cyclin E overexpression and amplification in human tumours

Cyclin E amplification and overexpression have recently been described in several tumour types. However, many tumour entities have never been examined for cyclin E alterations. Numerous and time-consuming experiments were previously required to determine the significance of potential oncogenes across different tumour types. To overcome this problem, tissue microarrays (TMAs) consisting of 3670 primary tumours from 128 different tumour types, 709 metastases, and 354 normal tissues were generated. Cyclin E alterations were then analysed by fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC). Cyclin E gene amplification was observed in 15 different tumour types and subtypes, ie rhabdomyosarcoma, urinary bladder cancer (three subtypes), ovarian cancer (two subtypes), malignant fibrous histiocytoma, adenocarcinoma of the small intestine, medullary breast cancer, gall bladder adenocarcinoma, phaeochromocytoma, gastric adenocarcinoma, squamous cell carcinoma of the uterine cervix, colonic adenocarcinoma, and endometrial carcinoma. Cyclin E protein accumulation was found in 48 different tumour types. The use of TMA technology has enabled us to expand considerably our knowledge of cyclin E alterations in human tumours. The occurrence of amplification and overexpression in many different tumour types suggests that cyclin E plays an important role in tumour biology.     

CYCLIN D1 OVEREXPRESSION IN NON-SMALL CELL LUNG CARCINOMA: CORRELATION WITH Ki67 LABELLING INDEX AND POOR CYTOPLASMIC DIFFERENTIATION

Cyclin D1 is part of the molecular system regulating the cell cycle G1 to S transition point. Its overexpression, a common finding in carcinomas of the breast, oesophagus, and head and neck, has also been demonstrated in a high percentage of non-small cell lung carcinomas (NSCLCs). The role of cyclin D1 in NSCLC has been studied by correlating its immunoreactivity with the Ki67 labelling index in paraffin-embedded, autoclaved surgical samples of 56 NSCLC cases. In addition, flow cytometric determination of ploidy and cell cycle status was carried out on 172 fresh tumour samples from the same cases. Twenty-four (42·8 per cent) NSCLCs showed positive cyclin D1 immunostaining, a finding which showed no relationship to ploidy pattern, cell cycle phase, histological subtype, or lymph node metastasis, but was significantly associated with the Ki67 labelling index ( P =0·03) and with poor cytoplasmic differentiation ( P =0·01). Cyclin D1-positive nuclei were abundant in poorly differentiated zones and absent in the best differentiated areas, particularly in heavily keratinized fields. These data indicate that in NSCLC, cyclin D1 overexpression is not only associated with a high cell proliferation rate, but also seems to play a role in the process of tumour differentiation.