Expression of cyclins,cyclin-dependent kinases and cyclin-dependent kinase inhibitors in oligodendrogliomas in humans

Cyclins are regulatory proteins of the cell cycle which bind and activate kinases. In gliomas, contrary to many malignancies, cyclin D1 is rarely amplified, but together with other cyclins, it increases with anaplasia. In a series of 23 surgical biopsies of grade II and III oligodendroglioma, cyclin D1, E, A, B1, CDK4-6, CDK2, Cdc2 and p27/Kip.1 have been studied by immunohistochemistry and Western blot. Cyclin D1 and A increased with anaplasia, showing a linear correlation with MIB.1 labeling index and an inverse correlation with p27/Kip.1 expression. Cyclin E and B1 and kinases were almost only expressed in grade III tumors. Normal oligodendrocytes and microglia cells of the cortex and white matter showed a clear positivity for cyclin D1, but not for other cyclins or kinases.     

Inducible nitric oxide synthase expression in benign and malignant cutaneous melanocytic lesions

Nitric oxide (NO) is synthesized by nitric oxide synthases (NOS) and plays an important role in tumour growth. In this study, inducible NOS (iNOS) expression was evaluated by immunohistochemistry in 34 melanocytic naevi (13 common melanocytic naevi, six Spitz naevi, and 15 so-called 'dysplastic naevi'), ten cutaneous melanomas in situ, 50 stage I invasive melanomas, and eight subcutaneous metastases of melanoma. In addition, four samples of melanocytic naevi and four samples of invasive melanomas were collected in order to perform western blot and northern blot analysis. By immunohistochemistry, melanocytic naevi never expressed iNOS. Among cases of melanoma in situ, two were negative, seven displayed staining in less than 20% of melanoma cells, and positivity was observed in 21-50% of melanoma cells in only one case. iNOS expression was detected in 46 out of 50 invasive melanomas (92%). Among these cases, 18 showed positivity in less than 20% of melanoma cells, 18 showed positivity in 21-50% of melanoma cells, and ten showed iNOS expression in more than 50% of cells. Statistical analysis revealed a significant difference in iNOS expression between melanocytic naevi and cutaneous melanomas (p<0.001). In addition, iNOS expression was significantly higher in invasive melanomas than in melanomas in situ (p=0.01). Among primary cutaneous melanomas, no significant correlation was found between iNOS expression and histopathological parameters (histotype, level, thickness and presence of regression/inflammatory infiltrate) and disease-specific survival. In subcutaneous melanoma metastases, iNOS expression was diffuse in more than 50% of cells. Statistical analysis revealed that subcutaneous melanoma metastases showed greater iNOS immunoreactivity than invasive melanomas (p=0.02). Molecular analyses confirmed that iNOS mRNA and protein were highly expressed in melanoma samples. In conclusion, iNOS was constantly absent in melanocytic naevi, whereas it was frequently expressed in melanomas, with up-regulation of the enzyme paralleling tumour progression. These data suggest that iNOS may play a role in the malignant transformation of melanocytes and in tumour growth. In addition, iNOS may be useful as an immunohistochemical marker for malignant melanocytic lesions.     

Reduced expression of p16 and p27 is correlated with tumour progression in cutaneous melanoma

AIMS: To determine if the cyclin dependent kinase inhibitors (CDKIs) p16 and p27 show reduced expression in the progression from benign to malignant melanocytic tumours, and to correlate these findings with patient prognosis. METHODS: Ninety-two melanocytic tumours were assessed for immunohistochemical expression of p16 and p27. These specimens included nine compound naevi, 10 dysplastic naevi, 17 thin (<1 mm) melanomas, 22 thick (>1 mm) melanomas, nine in-transit metastases, 13 lymph node metastases, and 12 soft tissue metastases. Clinicopathological information on the 39 patients with melanoma primaries was obtained from the Sydney Melanoma Unit database. The median follow up period was 43.3 months. RESULTS: A significant loss of expression of p16 and p27 was found with tumour progression. Positive expression of p27 was found in all compound and dysplastic naevi but only 43.6% of melanoma primaries. Expression of p27 was greater in lymph node and in-transit metastases (63.6%), but lower in soft tissue metastases (36.4%). Positive expression of nuclear p16 was evident in 73.7% of benign naevi, 28.2% of primary melanomas and 14.7% of metastatic melanomas. Neither p16 nor p27 expression was significantly correlated with overall survival, disease free survival or other clinicopathological markers. CONCLUSIONS: The CDKIs p16 and p27 are associated with tumour progression in melanoma, but do not reliably predict recurrence or survival.     

Cyclin D1 expression in melanocytic lesions of the skin

BACKGROUND: Progression through the cell cycle is controlled by cyclins, cyclin-dependent kinases, and cyclin-dependent kinase inhibitory proteins. The role of cyclin D1 in the development and progression of melanomas is controversial. The goal of this study is to evaluate the role of cyclin D1 in benign and malignant melanocytic lesions of the skin. METHODS: A total of 126 pigmented lesions of the skin including compound nevi (21), intradermal nevi (18), melanoma in situ (28), primary invasive melanomas (30), and metastatic melanoma (29) were evaluated for cyclin D1 expression. The following tiered system was used for scoring: 0% nuclear staining (score 0), 1% to 19% nuclear staining (score 1), 20% to 49% nuclear staining (score 2), and 50% or greater nuclear staining (score 3). RESULTS: Average scores were significantly higher for primary melanomas compared with nevi and for in situ melanomas compared with primary invasive melanomas. The average score for metastatic melanomas was not significantly different compared with primary invasive melanomas. Scores for primary invasive melanomas did not correlate with depth of invasion or presence of metastases. Compound nevi exhibited a slightly higher level of cyclin D1 expression compared with intradermal nevi. CONCLUSION: Although primary melanomas show a higher level of cyclin D1 expression compared with nevi, cyclin D1 appears to have little role in development of a metastatic phenotype. It is not clear why lesions localized near the dermal-epidermal junction express higher levels of cyclin D1. Further studies are indicated to ascertain the biologic role and practical utility of cyclin D1 in melanocytic lesions of the skin.     

Aberrant expression of the Rb pathway proteins in soft tissue sarcomas.

Cell cycle regulation depends on a fine balance between cyclins, cyclin-dependent kinases (CDKs), and cyclin-dependent kinase inhibitors (CKIs) that block the cycle progression. Alterations of the cell cycle regulators are a common feature of many malignant tumors, and some have been shown to have prognostic significance. In this study, 152 cases of different types of soft tissue sarcomas were evaluated for alterations of cell cycle regulator proteins that control the cell cycle progression from G1 to S phase and govern the Rb pathway. Immunohistochemical stains for proteins Rb, E2F1, cyclin D1, CDK4, CDK6, p16, and p27 were carried out on tissue microarrays. The relationship between the expression of these proteins and the histologic grade of the sarcomas was assessed. Altered expression for Rb and p16 proteins was identified in 67.8% and 65.1% of the cases, respectively. Overexpression of E2F1, cyclin D1, CDK4, and CDK6 was detected in 50.7%, 24.3%, 92.1%, and 10.5%, respectively. Overexpression of E2F1 was associated with altered expression of Rb protein. Overexpression of cyclin D1, CDK4, and CDK6 showed an association with normal Rb expression. CDK6 expression revealed a positive correlation with the histologic grade of the sarcoma, and p27 expression was inversely correlated with sarcoma grade. These results suggest that alterations of the Rb pathway proteins are common in soft tissue sarcomas and may participate in their tumorigenesis. CDK6 and p27 showed correlation with the histologic grade of the sarcomas, suggesting that these proteins could be used as prognostic markers.     

线粒体铁蛋白过表达抑制神经肿瘤细胞的增长与细胞铁代谢及细胞周期蛋白表达相关

目的 探讨过表达线粒体铁蛋白（MtFt） 抑制成神经母细胞瘤SH-SY5Y细胞的增殖机制。方法 以过表达MtFt的成神经母细胞瘤细胞MtFt-SY5Y为实验模型,野生型SH-SY5Y和pcDNA3.1-SY5Y（空质粒对照）为实验对照,运用流式细胞术、Western blotting技术等检测了MtFt对SH-SY5Y肿瘤细胞增殖的影响及铁代谢相关蛋白转铁蛋白受体1 （TfR1）,铁蛋白和细胞周期相关蛋白（cyclin）及其依赖性激酶（CDK）、cyclinD1、CDK4、cyclinE、CDK2的表达变化。结果 MtFt过表达通过调节细胞内铁代谢显著抑制了神经肿瘤细胞SH-SY5Y的增殖,与对照组相比,MtFt-SY5Y细胞增殖速度慢了近4倍。MtFt造成了细胞质内铁缺乏, TfR1表达显著上调,而铁蛋白H 亚基（H-ferritin）显著下调。同时 cyclinD1与CDK2蛋白表达显著降低,cyclinE蛋白表达显著上升,CDK4蛋白表达无显著性差异。结论 MtFt过表达能够显著抑制神经肿瘤细胞的生长,其机制可能是通过调节细胞内铁代谢,从而影响细胞周期相关蛋白及其周期蛋白激酶的表达。     

Cell Cycle Regulatory Proteins p27(kip), Cyclins Dl and E and Proliferative Activity in Oncocytic (Hurthle Cell) Lesions of the Thyroid

Cyclins are prime cell-cycle regulators central to the control of cell proliferation in eukaryotic cells. The formation of cyclin/cyclin-dependent kinases (CDK) complexes activates the kinases and initiates a cascade of events, which directs cells through the cell cycle. CDK inhibitors (CDKIs) such as p27^kip1 inhibit cyclin-CDK complexes and function as negative regulators of the cell cycle. Previous studies have shown that p27^kip1 is decreased in malignant relative to benign thyroid tumors, but its role and interaction with other cell cycle regulatory proteins have not been well established in oncocytic lesions of the thyroid. We studied the expression of p27^kip1, cyclins D1 and E, and Ki67 in 20 cases of oncocytic adenoma (AD), 6 cases of oncocytic carcinoma (CA), 8 cases of Hashimoto’s thyroiditis (HT), and 9 cases of nodular goiter with oncocytic change (NG) by immunohistochemistry. In the latter two lesions only oncocytic cells were evaluated. The positive staining was stratified into four groups. Statistical analysis was done using the Kruskal-Wallis one-way analysis of variance test, and, when significant, the Dunn multiple-comparisons procedure was used to determine pairwise differences. All 20 AD were p27^kip1 positive, 10 were 4+, 2 were 3+, and the remaining 8 were 1+. In contrast all 6 CA showed 4+ p27^kip1 staining, of the 8 HT, 2 were 4+, two 3+, three 1+, and 1 was negative. All 9 NG were p27 positive, 7 showed 4+, one 3+, and one 1+ staining. On pairwise comparison differences in p27^kip1 staining between AD and CA and between HT and CA were statistically significant (p=0.0243 and p=0.0142, respectively). In all but one case Ki67 expression was either very low (<3%) or negative. No significant differences were seen in the expression of cyclin D1 or cyclin E among the groups observed. In conclusion, the increased p27^kip1 expression in malignant oncocytic tumors relative to benign oncocytic lesions is unlike any other malignant progression reported in the thyroid and other organ systems in the body. This may reflect on the biologic nature of the oncocytic cells of the thyroid and the significance of this finding remains to be established. Proliferative activity as studied by Ki67 immunostaining was not helpful in distinguishing benign from malignant oncocytic tumors.     

原发性肝细胞癌中5种细胞周期蛋白的表达及其临床意义

目的探讨原发性肝细胞癌中5种细胞周期蛋白(cyclin)的表达及其与肝癌细胞的增殖状态、侵袭转移和乙型肝炎病毒(HBV)感染的相关性。方法应用Instrumedics公司生产的组织芯片制作仪,将273例原发性肝癌组织、144例癌旁肝组织和10例尸检非肝病死亡肝组织制成组织芯片,取样针直径2．0am,采用免疫组织化学方法分别检测了cyclin A、cyclin B、cyclin D1、cyclin D3及cyclin E在肝癌、癌旁肝及尸检肝组织的表达率,并分析了肝癌、癌旁肝组织中HBV感染与这5种cyclin表达间的相关性。结果共获得3个肝癌组织芯片蜡块,分别含136、143和148个位点。在273例肝癌组织标本中5种cyclin的阳性表达率分别为cyclin A 52．7％、cyclin B 45．4％、cyclin D1 35．9％、cyclin D3 44．3％和cyclin E 23．1％;在144例癌旁肝组织中分别为8．3％、5．6％、4．9％、6．3％和1．4％;10例尸检肝组织除1例cyclin D1阳性外,其余均为阴性。5种cyclin在肝癌组织中的阳性表达率均显著高于癌旁肝组织(P＜0．01);组织学分级为Ⅱ、Ⅲ级的肝癌组织5种cyclin的表达高于Ⅰ级(P＜0．05);除cyclinA外,伴有门静脉癌栓组的阳性率高于无癌栓组(P＜0．01);HBV感染与cyclin的表达无明显相关性(P＞0．05)。结论各个cyclin在肝癌细胞中呈不同程度的高表达,使癌细胞周期缩短,处于细胞增殖活跃状态,并有利于肝癌细胞的侵袭转移;未发现与HBV感染有关。     

Inverse correlation between high level expression of cyclin E and proliferation index in transitional cell carcinoma of the bladder.

BACKGROUND/AIMS: Overexpression of the G1 cyclins, D1 and E, and/or downregulation of p27(Kip1) allow uncontrolled tumour cell proliferation. This study investigated the relation between these three cell cycle proteins and tumour proliferation in bladder cancer. METHOD: Nuclear expression of cyclin D1, cyclin E, and p27(Kip1) was determined immunohistochemically in 52 primary transitional cell carcinomas, and the Ki-67 proliferation marker was also assessed. For each protein, the percentage of positive tumour cell nuclei was determined and analysed as a continuous variable. RESULTS: Advancing tumour grade and pathological stage were accompanied by increasing proliferation indices, but decreasing p27(Kip1) and cyclin D1 expression, with no significant change in cyclin E expression. Overall, cyclin D1 and E expression did not correlate with proliferation. However, in cyclin D1 overexpressing tumours (> or = 5% nuclei positive), the level of cyclin D1 expression positively correlated with proliferation. The correlation between cyclin E expression and proliferation changed from positive to negative with increasing levels of cyclin E expression, accompanied by a coordinate increase in p27(Kip1) expression. Overall, there was an inverse association between p27(Kip1) expression and proliferation. However, a subset of tumours displayed high proliferation indices despite high p27(Kip1) expression. The G1 cyclin index (sum of the level of expression of cyclins D1 and E) correlated positively with proliferation in superficial but not muscle invasive tumours. This correlation was stronger when the G1 cyclin index was adjusted for p27(Kip1) expression. CONCLUSION: These findings support a role for these proteins in the proliferation, differentiation, and progression of bladder transitional cell carcinomas.     

TETRANECTIN AND PLASMIN/PLASMINOGEN ARE SIMILARLY DISTRIBUTED AT THE INVASIVE FRONT OF CUTANEOUS MELANOMA LESIONS

The induction of expression of the components of the proteolytic plasminogen activation system in cutaneous melanocytic tumour progression has previously been reported. Plasminogen activators, their inhibitors, and the receptor for urokinase were present only in advanced primary melanomas and melanoma metastases. The present study reports on the presence of tetranectin and plasmin/plasminogen, two proteins connected with plasminogen activation, in cutaneous melanocytic lesions. The distribution of tetranectin and plasminogen was studied by immunohistochemistry in 105 freshly frozen melanocytic lesions of common naevocellular naevi ( n =24), atypical naevi ( n =14), early ( n =12) and advanced ( n =20) primary melanomas, and melanoma metastases ( n =35). Both tetranectin and plasminogen were detected in a variety of tissue components. In all stages of melanocytic tumour progression, tetranectin was found in endothelium, perivascular dendritic cells, and leukocytes. Plasminogen was present in endothelium and in the basal layer of the normal skin. Tetranectin and plasminogen staining of fibroblastic cells at the invasive front and of extracellular matrix was, however, restricted to malignant lesions. Co-localization of tetranectin and plasminogen was found in 50 per cent of the early primary melanomas and in more than 75 per cent of the advanced melanomas and melanoma metastases. These results suggest a coordinated role for tetranectin and plasminogen at the invasive front of melanomas. Tetranectin-bound plasminogen may facilitate the migration of tumour cells.     

Determination of proliferating fractions in malignant melanomas by anti-PCNA/cyclin monoclonal antibody

An immunohistochemical study of melanocytic tumours using 19A2, a monoclonal antibody against proliferating cell nuclear antigen (PCNA/cyclin), was performed on tissues routinely processed with formalin fixation and paraffin embedding. In normal skin, keratinocytes of the suprabasal region in epidermis, the papillae and outer root sheath of hair follicles and the basal cells lining the lobules of sebaceous glands were stained in the nucleus. Other skin components, including basal and follicular melanocytes, did not demonstrate nuclear labelling. In addition, expression of PCNA/cyclin in keratinocytes was higher in sun-exposed skin compared with unexposed skin. In melanocytic lesions, PCNA/cyclin positive tumour cells increased in number and staining intensity according to the following progression: common melanocytic naevi; dysplastic naevi; primary melanomas; and metastatic melanomas. Expression of PCNA/cyclin, therefore, provides a useful marker for proliferation and tumour progression in skin.     

Expression of cyclin E and cyclin-dependent kinase 2 correlates with metastasis and prognosis in colorectal carcinoma

The expression of cyclin E and cyclin-dependent kinases 2 (CDK2) in metastatic foci, the relationship of their expression with some clinicopathologic characteristics, and the correlation of their expression with prognosis remain unclear. To examine the roles of their expression in the progression of colorectal carcinoma, 21 normal mucosa, 9 hyperplastic polyps, 58 adenomas, 17 adenocarcinoma in adenomas, 203 primary cancers, 21 lymph node metastases, and 10 hepatic metastases were immunohistochemically stained with anti-cyclin E, anti-CDK2, and anti-Ki67 antibodies. In the carcinogenic process, both cyclin E and CDK2 expressions increased significantly. From the primary to the lymph node-metastatic foci, cyclin E protein remained unchanged, but CDK2 increased significantly. From the primary to the liver-metastatic foci, cyclin E apparently decreased, and CDK2 was reduced almost to zero. In primary carcinomas, the reduction of cyclin E was significantly associated with large tumor size, mucinous type, venous invasion, deep infiltration, lymph nodal metastasis, peritoneal metastasis, advanced stage, and poor prognosis. Decreased CDK2 was obviously correlated with large tumor size, venous invasion, deep infiltration, hepatic metastasis, advanced stage, and poor prognosis. Increased cyclin E protein was related to elevated CDK2, which was further linked to higher Ki67. Thus, CDK2 overexpression could facilitate lymph node metastasis. The overexpression of cyclin E and CDK2 may mainly promote the progression of early cancer. Anti-cyclin E or anti-CDK2 chemotherapy should be targeted to the cancers with such overexpression.     

Expressions of cyclin E, A, and B1 in Hodgkin and Reed–Sternberg cells: Not suppressed by cyclin-dependent kinase inhibitor p21 expression

p21 Is involved in the control of the mammalian cell cycle through the binding and inhibition of cyclin-dependent kinases. The cyclins are dependent on the phases of the cell cycle, and divided into two classes: mitotic cyclins (A, B1, B2) and G1 cyclins (C, D1, D2, D3, E). The product of the p21 gene is a potent downstream effector of the p53 tumor-suppressor gene function. The Hodgkin and Reed- Sternberg (H & RS) cells in Hodgkin's disease are reported to frequently express p53, p21, and nuclear proliferative activity (Ki-67). To clarify the relationship of p21, p53 and cyclins, we performed the immunohistochemistry of p53, p21, Ki-67, cyclin D1, cyclin E, cyclin A and cyclin B1, using 11 cases with Hodgkin's disease. In addition, we performed p53 gene sequencing of exon 5-8, and in situ hybridization of Epstein-Barr virus (EBV) EBER-1 region, whose products have reported to induce the expression of cyclin D. In this study, in all cases, Ki-67 was expressed in almost all H & RS cells, and p53 and p21 were expressed in H & RS cells. No p53 gene mutations were detected in any case, and p53 protein overexpression did not correlate with p53 gene mutations. The number of p21-positive H & RS cells was significantly related with that of the p53-positive cells. The cyclins E, A, B1 and D1 were also expressed in H & RS cells. Unexpectedly, the expression of the cyclins was not suppressed by p21 and p53 expression. In addition, the existence of EBV was not related to the expression of cyclins. It is considered that H & RS cells are, indeed, in cell cycle and commonly express the cell cyclins, and that the cell cycle of H & RS cells may not be specifically fixed in the G1, S, G2 or M phases.     

Cyclin A expression in superficial spreading malignant melanomas correlates with clinical outcome.

The present study analysed by immunohistochemistry the protein level of cyclin A and Ki-67 in a panel of paraffin-embedded tissue obtained from 172 primary (110 superficial and 62 nodular) and 73 metastatic melanomas, and ten benign naevi. Since cyclin A exists in the same quaternary complex in the S-phase of the cell cycle as the cdk inhibitor p21WAF1/CIP1, the levels of the two proteins were compared. Cyclin A and Ki-67 were heterogeneously expressed in the malignant tumours, whereas in benign naevi, only rare positive cells were detected. In superficial spreading melanomas, the cyclin A level was related to tumour thickness, with less expression in thinner lesions (p<0.00001), and to Ki-67 (p<0.00001) and p21WAF1/CIP1 (p=0.01) scores. Multivariate analysis showed that in addition to the depth of the primary tumour, the protein level of cyclin A was an independent indicator of relapse-free period (thickness, p<0.00001; cyclin A, p=0.0003). In contrast, in nodular melanoma, the cyclin A level was associated with Ki-67 expression, but neither cyclin A nor Ki-67 was related to tumour thickness (cyclin A, p=0.06; Ki-67, p=0.61) and neither had any impact on relapse-free (cyclin A, p=0.64; Ki-67, p=0.32) or overall (cyclinA, p=0.94; Ki-67, p=0.45) survival. In conclusion, the results indicate that cyclin A is a strong prognostic factor for patients with superficial spreading melanomas. In nodular melanomas, the proliferation rate seems to have little impact on disease progression.     

Alterations in cadherin and catenin expression during the biological progression of melanocytic tumours.

AIMS: Compelling evidence from cell culture studies implicates cadherins in the neoplastic progression of melanocytic tumours but few reports describe the expression of cadherins and the related transmembrane proteins, catenins, in a full range of benign and malignant excised melanocytic tumours. METHODS: Using immunohistochemistry and western blotting after tissue fractionation, the pattern of expression of cadherins/catenins was studied in a range of surgically excised melanocytic tumours, from dysplastic naevi to stage III cutaneous metastatic malignant melanoma. RESULTS: Appropriate membranous expression of E-cadherins and P-cadherins is seen in dysplastic naevocytes with an epithelioid phenotype and is largely maintained with malignant transformation to radial growth phase melanoma and primary vertical growth phase malignant melanoma. Loss of membranous E-cadherin is seen in a small number of vertical growth phase melanomas only when metastasis has occurred. However, there is a concomitant dramatic loss of membranous P-cadherin expression in all melanomas at the same stage. A minority of metastatic melanomas show de novo membranous N-cadherin expression in comparison with dysplastic naevi and primary melanoma. Membranous expression of the desmosomal cadherin, desmoglein, was not seen in any tumour studied. Frequently, beta catenin is aberrantly produced in the cytoplasm of cells in dysplastic naevi and metastatic malignant melanoma, with an implied compromise to adhesive function. Furthermore, membranous gamma catenin expression was not seen in any of the 70 melanocytic tumours studied, implying obligatory transmembrane binding of cadherins to beta catenin for maintenance of adhesive function. CONCLUSIONS: The most important alterations in membranous cadherin and catenin expression are seen late in the biological progression of melanocytic tumours at the stage of "in transit" or regional lymph node metastasis, with implications for tumour growth, invasion, and dissemination.     

Alterations in cadherin and catenin expression during the biological progression of melanocytic tumours.

AIMS: Compelling evidence from cell culture studies implicates cadherins in the neoplastic progression of melanocytic tumours but few reports describe the expression of cadherins and the related transmembrane proteins, catenins, in a full range of benign and malignant excised melanocytic tumours. METHODS: Using immunohistochemistry and western blotting after tissue fractionation, the pattern of expression of cadherins/catenins was studied in a range of surgically excised melanocytic tumours, from dysplastic naevi to stage III cutaneous metastatic malignant melanoma. RESULTS: Appropriate membranous expression of E-cadherins and P-cadherins is seen in dysplastic naevocytes with an epithelioid phenotype and is largely maintained with malignant transformation to radial growth phase melanoma and primary vertical growth phase malignant melanoma. Loss of membranous E-cadherin is seen in a small number of vertical growth phase melanomas only when metastasis has occurred. However, there is a concomitant dramatic loss of membranous P-cadherin expression in all melanomas at the same stage. A minority of metastatic melanomas show de novo membranous N-cadherin expression in comparison with dysplastic naevi and primary melanoma. Membranous expression of the desmosomal cadherin, desmoglein, was not seen in any tumour studied. Frequently, beta catenin is aberrantly produced in the cytoplasm of cells in dysplastic naevi and metastatic malignant melanoma, with an implied compromise to adhesive function. Furthermore, membranous gamma catenin expression was not seen in any of the 70 melanocytic tumours studied, implying obligatory transmembrane binding of cadherins to beta catenin for maintenance of adhesive function. CONCLUSIONS: The most important alterations in membranous cadherin and catenin expression are seen late in the biological progression of melanocytic tumours at the stage of "in transit" or regional lymph node metastasis, with implications for tumour growth, invasion, and dissemination.     

Expression and gene amplification of primary (A, B1, D1, D3, and E) and secondary (C and H) cyclins in colon adenocarcinomas and correlation with patient outcome

BACKGROUND/AIMS: Deregulation of cell cycle control is a hallmark of cancer. The primary cyclins (A, B1, D1, D3, and E) are crucial for cell cycle progression. Secondary cyclins (C and H) have putative indirect effects on cell cycle progression and have not previously been evaluated in colon cancer. This study examined cyclin protein expression and gene amplification in colon adenocarcinoma and the correlation with patient outcome. METHODS: Immunohistochemistry and real time quantitative polymerase chain reaction were used to determine cyclin expression and gene amplification in 219 tumours. The results were compared with clinical variables and patient outcomes. RESULTS: Cyclin H was overexpressed in all tumours, cyclin C in 88%, cyclin B1 in 58%, cyclin A in 83%, cyclin D3 in 36%, cyclin E in 25%, and cyclin D1 in 11% of the tumours. Extra gene copies of cyclin A were seen in 6.2% of the tumours, cyclin B1 in 9%, cyclin C in 26.9%, cyclin D1 in 55%, cyclin D3 in 20.5%, cyclin E in 19.1%, and cyclin H in 5.1%. A significant correlation between protein overexpression and gene amplification was seen for cyclin C only. High expression of cyclin A was independently associated with improved survival. Amplification of cyclin C was independently associated with an unfavourable prognosis. CONCLUSIONS: Amplification of the cyclin C gene was related to an unfavourable prognosis and high protein expression of cyclin A was associated with a better outcome in colon adenocarcinoma.