Peroxisome proliferator-activated receptors in squamous cell carcinoma and its precursors

BACKGROUND: Peroxisome proliferator-activated receptors (PPARs) mediate several functions that are of interest in carcinogenesis. Although PPARalpha, PPARbeta, and PPARgamma are expressed in multiple human, their expression has not been investigated in non-melanoma skin cancer. METHODS: We performed a retrospective paired immunohistochemical analysis of normal skin, actinic keratosis (AK), and squamous cell carcinoma (SCC) among 35 individuals. Specimens were considered PPAR immunoreactive when 1% or more of the tumor cells showed clear evidence of immunostaining. Cyclooxygenase-2 (COX-2) expression, the fraction of proliferating endothelial cells, and microvessel density were also evaluated in these samples. RESULTS: PPARalpha immunoreactivity was significantly less likely to occur in SCC and AK than in normal skin of each individual. In contrast to PPARalpha, PPARbeta appeared to be upregulated in (pre)malignant skin lesions. For each individual, the likelihood that normal skin, AK, or SCC was immunoreactive against PPARgamma was comparable. COX-2 immunopositivity was significantly associated with PPARbeta and PPARgamma immunoreactivity. No statistical differences were noted for the angiogenesis parameters and PPARalpha, PPARbeta, or PPARgamma expression, except that the microvessel density was significantly higher among PPARbeta-immunoreactive SCCs compared to that among immunonegative SCCs. CONCLUSION: Although further research is warranted, these results suggest that PPAR ligands such as fibrates and thiazolidinediones may have chemoprophylactic properties in skin carcinogenesis.     

Immunohistochemical study of cyclooxygenase-2 and p53 expression in skin tumors

Overexpression of cyclooxygenase-2 (COX-2) has been demonstrated in various cancers, including experimentally promoted tumors, gastrointestinal cancers, breast tumors and skin tumors. The mechanism that controls COX-2 expression is not yet clear. Currently, it is reported that COX-2 expression is frequently associated with mutated p53 genes. The goal of this study was to evaluate the expression patterns of COX-2 and p53 in several skin tumors and their correlation. An immunohistochemical method was used to investigate the expression of COX-2 and p53 proteins on formalin-fixed, paraffin-embedded tissue specimens of squamous cell carcinomas (SCC), basal cell carcinomas (BCC), Bowen's disease (BD), actinic keratosis (AK) and porokeratosis. The expression of COX-2 increased in 50% (5/10) of SCC, 80% (8/10) of BCC, 40% (4/10) of BD, 50% (5/10) of AK, and 20% (2/10) of porokeratosis cases. The expression of p53 increased in 90% (9/10) of SCC, 70% (7/10) of BCC, 70% (7/10) of BD, 50% (5/10) of AK, and 40% (4/10) of porokeratosis cases. COX-2 positivity rates of the p53-positive skin tumors were 56%, 100%, 57%, 80% and 25% in SCC, BCC, BD, AK and porokeratosis, respectively. However, the correlation between p53 and COX-2 expression in skin tumors was not statistically significant ( P  > 0.05). Our results indicate that skin COX-2 and p53 may play roles in skin tumors, but that there is no apparent correlation between the two markers.     

Increased expression of an epidermal stem cell marker, cytokeratin 19, in cutaneous squamous cell carcinoma

Background Cytokeratin 19 (CK19) has been considered to be a putative marker for epidermal stem cells in the hair follicle bulge. Cumulative reports have shown that epidermal stem cells play an important role in skin carcinogenesis. However, to date there has been no report on the clinical alteration of the stem cells in squamous cell carcinoma (SCC). Objectives To investigate alteration of the stem cells and proliferating cells and to assess their relationship and potential contribution to SCC. Methods Thirty paraffin‐embedded neoplastic skin lesions, consisting of 10 cases each of actinic keratosis (AK), Bowen disease (BD) and SCC, were examined immunohistologically for CK19 and Ki‐67. Results Positive reactivity for CK19 was seen in 30% of AK, 50% of BD and 80% of SCC lesions. There was significantly higher expression levels of CK19 in SCC than in AK and BD (P < 0·05). In addition, BD lesions harboured a significantly higher number of CK19‐positive cells than did AK lesions (P < 0·05). There were significant differences in Ki‐67 labelling indices between AK and BD and between AK and SCC (P < 0·001), but not between BD and SCC (P > 0·05). Furthermore, a serial section comparison study showed that there was a minor population of cells co‐expressing CK19 and Ki‐67 in a subset of the tumour cells of SCC samples. The percentage of CK19+ cells significantly correlated with that of Ki67+ cells in all examined neoplastic skin lesions. Conclusions These results suggest that CK19 expression may be associated with the retention of stem cell characteristics or a state that is uncommitted to terminal squamous differentiation.     

表皮肿瘤中COX-2与P53的检测

目的了解表皮肿瘤组织环氧合酶-2(COX-2)与P53的表达情况。方法免疫组化法检测脂溢性角化病(SK)15例、Bowen’s病(BD)15例、基底细胞上皮瘤(BCE)20例、鳞癌(SCC)20例COX-2和P53的表达。结果所检测的各肿瘤组织标本均有COX-2的表达,分别为SCC95%,BD73.3%,SK46.6%,BCE68.0%,表达强度以SCC最为显著,周围正常组织未见表达。突变型P53在SCC(80.0%),BCE(75.0%),BD(33.3%)肿瘤组织的阳性率较高,而在SK(13.3%)中基本不表达。SCC和BCECOX-2表达阳性者其突变型P53表达的阳性率较COX-2表达阴性者高(P<0.05)。结论表皮肿瘤存在COX-2的过表达;P53的突变与COX-2的过表达有关,p53突变可能是通过上调COX-2水平发挥抗凋亡作用,从而促进SCC,BCE的形成和发展。     

Raptor、Rictor和磷酸化Akt在日光性角化病、Bowen病及鳞状细胞癌中的表达

目的:检测Raptor、Rictor和磷酸化Akt(p-Akt)在日光性角化病、Bowen病和鳞状细胞癌中的表达。方法:采用免疫组化法检测Raptor、Rictor及p-Akt(Ser473)在20例正常皮肤、20例日光性角化病、20例Bowen病及40例鳞状细胞癌中的表达。结果:Raptor在鳞状细胞癌、Bowen病和日光性角化病中的阳性表达率分别为87.50%、70.00%和60.00%,均高于正常皮肤的25.00%(均P0.05);其中低分化鳞状细胞癌中Raptor的阳性表达率为100%,高于高分化鳞状细胞癌的阳性表达率75%(P0.05)。Rictor在鳞状细胞癌、Bowen病和日光性角化病中的阳性表达率分别为80.00%、70.00%及55.00%,均高于正常皮肤阳性表达率的20%(均P0.05);p-Akt(Ser473)在鳞状细胞癌、Bowen病和日光性角化病中的阳性表达率分别为77.50%、65.00%及50.00%,而正常皮肤阳性表达率为0。鳞状细胞癌、Bowen病和日光性角化病中Rictor的阳性表达水平和p-Akt(Ser473)的阳性表达水平均呈正相关(均P0.05)。结论:Raptor、Rictor和p-Akt(Ser473)的高表达可能与日光性角化病、Bowen病和鳞状细胞癌的发生发展有关。     

蛋白激酶D1及其磷酸化位点在皮肤鳞状细胞癌、Bowen病及光线性角化病组织中的表达

目的 探讨蛋白激酶DI(PKD1)及其磷酸化位点pPKD1-tyr463和pPKD1-ser916在鳞状细胞癌(SCC)、Bowen病和光线性角化病(AK)中的表达及意义.方法 收集新鲜SCC、Bowen病、AK及正常皮肤组织各10份,RT-PCR法检测各组样本中PKD1在基因水平的表达,Western印迹法检测各组样本中PKD1及其磷酸化位点在蛋白水平的表达.另收集蜡块组织SCC 50份、Bowen病20份、AK 20份及正常表皮组织10份,免疫组化检测PKD1、pPKD1-tyr463及pPKD1-ser916的表达情况.结果 正常皮肤组织、SCC、Bowen病和AK组织中PRKD1 mRNA的表达量分别为0.64±0.09、5.37±1.06、2.69±0.72和2.43±0.46,4组间差异有统计学意义(F=21.37,P＜0.05),且SCC、Bowen病和AK组织的表达水平均显著高于正常组织(P＜0.05),SCC组织又显著高于AK和Bowen病组织(均P＜ 0.05),而Bowen病与AK组织的表达量差异无统计学意义(P＞0.05).PKD1总蛋白及pPKD1-tyr463在SCC和Bowen病组织中主要表达在棘层细胞及异形细胞的细胞质和细胞膜,且阳性表达率均显著高于正常皮肤组和AK组(均P＜0.01);pPKD1-ser916仅在部分高分化SCC癌巢中少量表达,而低分化鳞癌、AK、Bowen病及正常皮肤组织中均未见表达;SCC组中PKD1阳性表达率随鳞癌病理分级的提高而增加,且PKD1与pPKD1-tyr463的表达呈正相关(rcc=0.479,P＜0.05).Western印迹检测结果与免疫组化检测结果大致相符.结论 PKD1及其磷酸化位点Tyr463可能参与复层鳞状上皮来源的皮肤肿瘤的形成和进一步发展分化,在皮肤SCC形成进程中PKD1可能通过Tyr463位点活化而发挥促进作用.     

Expression of granulocyte colony-stimulating factor and its receptor in epithelial skin tumors

Granulocyte colony-stimulating factor receptors (G-CSFR) have been observed on the surface of not only hematopoietic cells but also several cancer cells. In the present study, we investigated the expression of G-CSFR or G-CSF in epithelial skin tumors by immunohistochemical staining. The assessments were defined by the percentage of G-CSFR or G-CSF positive cells and expressed as G-CSFR and G-CSF scores. The G-CSFR score in SCC (77.6+/-20.0%) was significantly higher than that in Bowen's disease (BD) (51.0+/-35.6%), actinic keratosis (AK) (49.3+/-34.6%) or normal skin (30.0+/-32.1%) (P=0.0004, P=0.0003, P<0.0001, respectively). The mean G-CSF score in SCC (56.7+/-27.4%) or in BD (44.1+/-31.4%) was higher than that in normal skin (24.9+/-25.8%) (P=0.0075, P<0.001, respectively). G-CSF expression in AK (29.8+/-31.2%) was lower than that in SCC (P=0.0037). There was significant positive correlation between the G-CSFR score and the G-CSF score (gamma=0.274, P=0.0107) in skin tumors. These findings suggested that the assessment of G-CSFR expression might be associated with carcinogenesis of skin tumors.     

环氧化酶-2在表皮肿瘤中的表达

目的 探讨环氧化酶-2在不同表皮肿瘤中的表达及意义。方法 选择鳞状细胞癌8例、基底细胞上皮瘤10例、Bowen病8例和脂溢性角化病12例,运用免疫组化方法观察肿瘤细胞中环氧化酶-2的表达。结果 与正常表皮相比,环氧化酶-2在鳞状细胞癌、Bowen病、基底细胞上皮瘤中的表达明显上调,尤其以鳞状细胞癌中的表达最强。而环氧化酶-2在脂溢性角化病中的表达与正常人皮肤的表达近似。结论 环氧化酶-2表达的上调可能在表皮肿瘤的发生发展中发挥一定作用。     

NUAK2 localization in normal skin and its expression in a variety of skin tumors with YAP

BackgroundNUAK2 is a critical gene that participates in the carcinogenesis of various types of cancers including melanomas. However, the expression patterns of NUAK2 in normal skin and in various types of skin tumors have not been fully elucidated to date.ObjectivesTo elucidate the distribution and localization of NUAK2 expression in normal skin, and characterize the expression patterns of NUAK2 and YAP in various types of skin tumors.MethodsIn this study, we characterized the expression of NUAK2 in tissues by developing a novel NUAK2-specific monoclonal antibody and using that to determine NUAK2 expression patterns in normal skin and in 155 cases of various types of skin tumors, including extramammary Paget’s disease (EMPD), squamous cell carcinoma (SCC), Bowen’s disease (BD), actinic keratosis (AK), basal cell carcinoma (BCC) and angiosarcoma (AS). Further, we analyzed the expression patterns of YAP and p-Akt in those tumors.ResultsOur analyses revealed that NUAK2 is expressed at high frequencies in EMPD, SCC, BD, AK, BCC and AS. The expression of p-Akt was positively correlated with tumor size in EMPD (P = 0.001). Importantly, the expression of NUAK2 was significantly correlated with YAP in SCC (P = 0.012) and in BD (P = 0.009).ConclusionsOur results suggest that the YAP-NUAK2 axis has critical importance in the tumorigenesis of SCC and BD, and that therapeutic modalities targeting the YAP-NUAK2 axis may be an effective approach against skin tumors including SCC and BD.     

An assessment of the malignant potential of actinic keratoses and Bowen's disease: p53 and PCNA expression pattern correlate with the number of desmosomes

Actinic keratoses (AK) and Bowen's disease (BD), both intraepidermal skin tumors, have a potential progression to squamous cell carcinoma (SCC). To evaluate the malignant potential of AK and BD, the expression pattern of p53 protein and proliferating cell nuclear antigen (PCNA) were examined in five types of AK and BD by immunohistochemistry. The ultrastructural difference of epidermal cells between AK and BD lesions was investigated. In the study of p53 and PCNA expression, the atrophic and acantholytic types of AK showed lower positive rates compared to others. These two types did not demonstrate all layers expression pattern. The number of desmosomes of the epidermal cells was significantly reduced in BD, and in the bowenoid and hypertrophic types of AK compared with other types of AK The number of hemi-desmosomes showed greatest reduction in BD and the bowenoid type of AK On the basis of our findings, it is hypothesized that atrophic and acantholytic types of AK may have the lowest, and the bowenoid type of AK and BD may have the highest, malignant potential.     

Lamin expression in normal human skin,actinic keratosis,squamous cell carcinoma and basal cell carcinoma

BACKGROUND: Aberrant expression patterns of nuclear lamins have been described in various types of cancer depending on the subtype of cancer, its aggressiveness, proliferative capacity and degree of differentiation. In general, the expression of A-type lamins (lamins A and C) has been correlated with a non-proliferating, differentiated state of cells and tissues. OBJECTIVES: To establish and compare the expression patterns of lamins in normal human skin, actinic keratosis (AK), squamous cell carcinoma (SCC) and basal cell carcinoma (BCC). METHODS: Expression patterns of the individual lamin subtypes were studied immunohistochemically. The proliferation capacity of the tumour cells was detected using a specific antibody to Ki-67, and was related to the A-type lamin expression patterns. RESULTS: In normal skin, lamin A was expressed in the suprabasal cell compartment of the epidermis, whereas the basal cells were mostly unstained. BCCs and SCCs stained positive in most cells, while the epidermis overlying BCC and SCC and the epidermis in AK stained homogeneously and strongly in the basal cells in addition to the suprabasal cells. Lamin C was expressed in some basal cells of normal epidermis while the suprabasal cells stained strongly positive. Both BCCs and SCCs stained strongly positive for lamin C, with the difference that in BCC the staining was predominantly present in nucleolar structures with occasional staining of the nuclear envelope. The epidermis overlying SCC showed strong positivity in the lamina of virtually all cells. The expression of lamin C in the basal cells of AK resembled the expression pattern seen in the epidermis overlying BCC, i.e. a nucleolar staining next to nuclear envelope staining. Lamin B1 and B2 were found in virtually all cells in normal epidermis, AK, BCC, SCC and the epidermis overlying cancer. The percentage of Ki-67-expressing cells was highest in BCC (45%), and gradually decreased via epidermis overlying BCC, AK, SCC, and epidermis overlying SCC, to normal skin (11%). Simultaneous expression of A-type lamins and Ki-67 occurred in approximately 50% of the proliferating (Ki-67 positive) cells in BCC and SCC. CONCLUSIONS: Significant changes occur in the expression patterns of A-type lamins in both premalignant and malignant lesions of the skin. The profound overlap of lamin A and Ki-67 staining patterns indicates that the proliferating tumour cells may obtain a certain degree of differentiation. Finally, lamin A expression in the basal cell layer of the apparently normal epidermis overlying BCC may suggest its involvement in the primary process.     

Activation of fibroblast growth factor receptor 3 and oncogene-induced senescence in skin tumours

Background  The activation of oncogenes is an important step in tumorigenesis, and recently, oncogene-induced senescence (OIS) was proposed as a critical barrier against malignant transformation in normal primary cells.
Objectives  The aim of this study was to examine the activation of fibroblast growth factor receptor 3 (FGFR3) as an oncogene product and OIS in human skin tumours.
Methods  We investigated the activation of FGFR3 and OIS by mutation and immunohistochemical analysis in skin tumours, including seborrhoeic keratosis, actinic keratosis (AK), Bowen's disease (BD), basal cell carcinoma (BCC) and squamous cell carcinoma (SCC).
Results  Activated point mutations of FGFR3 were identified in four of 22 cases (18%) of seborrhoeic keratosis, but no mutation was detected in the other skin tumours. Twenty-seven of 31 cases (87%) of seborrhoeic keratosis showed moderately to strongly positive expression of the FGFR3 protein, but almost all the other skin tumours were negative. On the other hand, almost all the seborrhoeic keratoses showed negative immunoreactivity for antiphoshohistone H2AX (γ-H2AX) as a marker of OIS, but 17 of 22 cases (77%) of AK were moderately to strongly positive. Immunoreactivity for γ-H2AX was significantly greater in AK than in seborrhoeic keratosis, BD, BCC and SCC.
Conclusions  The activation of FGFR3 might be a common feature in the tumorigenesis in seborrhoeic keratosis, although the activation does not induce a typical oncogenic signal in keratinocytes. In addition, OIS due to some oncogenic signals rather than activation of FGFR3 might be involved in the early skin carcinogenesis related to chronic ultraviolet radiation exposure.     

环氧合酶-2和血管内皮生长因子mRNA在皮肤鳞状细胞癌组织中的表达

目的 探讨环氧合酶-2(COX-2)、血管内皮生长因子(VEGF)mRNA在皮肤鳞状细胞癌(SCC)和正常人皮肤组织中的表达以及它们之间相互关系。方法 应用逆转录-聚合酶链反应(RT-PCR)方法,检测24例SCC和10例正常人皮肤组织中COX-2和VEGF mRNA的表达。结果 RT-PCR结果显示,在正常人皮肤组织中COX-2和VEGF mRNA呈较弱表达或无表达,吸光度平均值分别为(0.01±0.01)和(0.02±0.02);有79.2%(19/24)SCC组织中COX-2 mRNA表达水平增高,平均值为(0.56±0.48),与正常皮肤组织比较差异有统计学意义(P<0.05);VEGF mRNA在SCC组织中全部高表达(24/ 24,100%),平均值为(0.66±0.35),与正常人皮肤组织比较差异有统计学意义(P<0.05)。经相关性分析两者之间的表达呈明显正相关(r=0.86)。结论 COX-2可能与SCC血管形成有关,且其作用可能通过上调VEGF通道来发挥作用。     

Cyclin A and beta-catenin expression in actinic keratosis, Bowen's disease and invasive squamous cell carcinoma of the skin

BACKGROUND: Actinic keratosis (AK) has been defined as a precancerous lesion or an early phase in the evolution of squamous cell carcinoma (SCC) and histological changes seen in the individual cells of an AK are indistinguishable from those seen in SCC, which invade the dermis. Cyclin A is an increasingly utilized proliferation marker that has functions in both S phase (DNA replication) and initiation of mitosis, whereas alterations of beta-catenin, the molecule involved in cell-cell adhesion and in signalling transduction, could promote invasive and proliferative capacities of malignant tumours. OBJECTIVES: To determine cyclin A and beta-catenin expression pattern in cutaneous SCC and in in situ lesions classified as keratinocytic intraepidermal neoplasia (KIN) and, using traditional terms, as AK and Bowen's disease (BD), and to analyse it in relation to SCC differentiation, diameter and thickness. METHODS: Immunohistochemical staining was performed on 110 formalin-fixed paraffin-embedded tissue samples with the streptavidin-biotin technique using antibodies to cyclin A and beta-catenin. On histological examination, 53 lesions were diagnosed as AK, 16 as BD and 41 as SCC-11 well differentiated (WD), 16 moderately differentiated (MD) and 14 poorly differentiated (PD). Using KIN classification, 22 lesions were KIN1, 23 were KIN2 and 24 were KIN3. For cyclin A, distribution and labelling index (LI), and for beta-catenin, level of membranous staining and presence of aberrant (nuclear/cytoplasmic) localization were examined. RESULTS: Diffuse cyclin A presence was observed more frequently in BD than in AK (P < 0.0001) or SCC (P = 0.0002), and in SCC-PD compared with SCC-WD (P < 0.0001) or SCC-MD (P = 0.0003). Differences between KIN3 and KIN2, as well as KIN3 and KIN1 lesions, were statistically significant (P < 0.0001), and the same result appeared when KIN1 and KIN2 cases were grouped and compared with those of KIN3 (P < 0.0001). Cyclin A LI was significantly lower (P < 0.05) in AK than in BD or SCC, but no difference between BD and SCC was found, and LI in BD was even higher than in SCC-WD or SCC-MD, while analysis regarding SCC differentiation and KIN classification revealed the same correlation as for the cyclin A distribution. Reduced or absent beta-catenin membranous staining was found in 90 cases (81.8%), more often in SCC than in AK (P = 0.03) or in AK and BD grouped together (P = 0.02). There was no statistical difference between SCCs of various level of differentiation, or between different KIN grades. Diffuse loss of membranous beta-catenin staining showed 36 lesions (32.7%), more frequently SCC than AK (P = 0.003) or AK and BD grouped (P = 0.006), as well as SCC-PD compared with SCC-WD (P = 0.01) and SCC-MD (P = 0.03), whereas all KIN comparisons remained nonsignificant. Aberrant beta-catenin cellular localization demonstrated 28 lesions (25.5%), most often in the basal or peripheral parts and in the lesions with diffuse beta-catenin loss (P = 0.009), but revealed no correlation with the histological type, SCC level of differentiation or KIN grades. Diffuse loss of membranous beta-catenin staining was found to be significantly more frequent in SCC thicker than 4 mm (P = 0.03), while all other comparisons between cyclin A or beta-catenin with the tumour size remained nonsignificant. Cyclin A LI was higher in cases with diffuse loss of membranous staining (P = 0.001) or with aberrant cellular localization of beta-catenin (P = 0.002). CONCLUSIONS: Cyclin A LI showed greater difference between AK and BD than between BD and SCC, suggesting that increased proliferation (measured by cyclin A LI) characterizes progression of in situ lesions from AK to BD, whereas reduced beta-catenin expression separates more clearly SCC from the in situ lesions. Diffuse pattern of loss of membranous beta-catenin staining correlated better with the type of lesion, SCC differentiation and tumour size than reduced expression in general or aberrant cellular localization of beta-catenin. KIN classification does not seem to be supported by our findings, except when KIN1 and KIN2 lesions (in situ, partial thickness) are grouped.     

p21 WAF1/cip1expression in non-melanoma skin tumors

Abnormal control of the cell cycle is closely linked to carcino-genesis. p21^WAF1/CIP1 protein is a universal inhibitor of Gl cyclin-dependent kinase and is induced by p53-dependent and -independent pathways. In order to elucidate the role of p21^WAF1/CIP1 in human skin carcinogenesis, protein expression in squamous cell carcinoma (SCC), basal cell carcinoma (BCC), Bowen's disease (BD), actinic keratosis (AK), keratoacanthoma (KA), seborrheic keratosis (SK), and normal skin was examined using an immunohistochemical method. In normal skin, a few positive cells were seen in some cases in the upper spinous layer of the epidermis; sebaceous glands also had positive cells. In cases of SK and KA, positive cells were found in the basal and suprabasal epidermal layers (proliferation pattern), and in cases of BD and AK, positive cells were seen mainly in the upper spinous layer (differentiation pattern). Cases of SCC had more positive cells and showed two staining patterns: proliferation, or mixed. Cases of BCC had no positive cells. p21^WAF1/CIP1 has some unidentified role in keratinocyte tumorigenesis, which may not be related directly to carcinogenesis.     

GLUT-1、Ki-67在皮肤肿瘤中的表达及意义

目的：探讨葡萄糖转运蛋白-1（GLUT-1）在脂溢性角化病（SK）、日光性角化病（AK）、Bowen病（BD）、鳞状细胞癌（SCC）中的表达及其与细胞增殖因子Ki-67之间的关系。方法：采用免疫组化法检测了95例不同皮肤肿瘤GLUT-1及Ki-67的表达。结果：GLUT-1及Ki-67在SK及正常皮肤都不表达,在AK、BD及SCC表达上调,并且二者的阳性表达强度间具有正相关性。结论：GLUT-1在恶性皮肤肿瘤中表达上调,与肿瘤的侵袭和转移有关。其表达强度可作为判断皮肤肿瘤恶性程度的检测指标,对诊断及鉴别诊断具有参考价值。     

Less expression of cyclin E in cutaneous squamous cell carcinomas than in benign and premalignant keratinocytic lesions

In a previous study, we showed that overexpression of cyclin D, a G1 cyclin, is frequently associated with keratinocyte carcinogenesis as an early event. Another G1 cyclin, cyclin E, was recently suggested to be a prognostic marker for breast cancer. In order to evaluate the role of cyclin E in human keratinocyte carcinogenesis, we analysed the expression of cyclin E by immunohistochemistry in normal skin, seborrheic kaeratosis (SK), keratoacanthoma (KA), actinic keratosis (AK), Bowen's disease (BD), basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Positive cells were seen rarely in normal epidermis, in 9 of 20 cases of SK, in 5 of 6 cases of KA, in 9 of 13 cases of AK and in all 27 cases of BD. Some of the cases of AK and BD had positive cells in the superficial epidermis, where atypicality is less obvious. In contrast, positive cells were seen in 4 of 25 cases of SCC and none of 15 cases of BCC. These results suggest that expression of cyclin E plays a role in the formation of benign and premalignant keratinocytic tumors, whereas down-regulation of cyclin E expression may be involved in carcinogenesis in human keratinocytes.     

Expression of bcl-2, p53 and Ki-67 in arsenical skin cancers

To investigate the regulation of apoptosis and proliferation in arsenic-induced skin cancers, we examined the expression of bcl-2. p53, and Ki-67 using immunohistochemical staining. Thirty patients with Bowen's disease (BD), ten with basal cell carcinoma (BCC), eight with squamous cell carcinoma (SCC) and eleven of perilesional normal skin (PLN) of the non-sun exposure sites from endemic area were examined. The results showed that: 1) bcl-2 was expressed in all of the BCC homogeneously, in none of the SCC, and in 12/30 of the BD focally or homogeneously; 2) p53 was expressed in all of the arsenical skin cancers with a labelling index of 75±14% of BD, 50±17% of BCC. 61±15% of SCC, and also in all of the perilesional normal skin with a labelling index of 55±24%; 3) Ki-67 was expressed in all of the skin cancers with labelling index of 58±17% of BD. 12±7% of BCC, 47±21% of SCC, and in 9/11 of PLN with a labelling index of 41±24%. Expression of bcl-2 in BCC or BD is related to the phenotype of germinative basal cell. The constant expression of bcl-2 i early dysplastic cells of BD and the earliest expression of P53 in the basal cells of perilesional normal skin indicate that the initial step of arsenic-induced carcinogenesis is from the basal germinative cells. There is no mutual relationship between bcl-2, p53 or Ki-67 expression in any type of the arsenical skin cancers, but there is a positive correlation between p53 and Ki-67 expression identified in perilesional normal skin. BD had the highest labelling index of p53 and Ki-67.     

Expression of RPE65, a putative receptor for plasma retinol-binding protein, in nonmelanocytic skin tumours

BACKGROUND: In a recent report we described RPE65, a protein originally characterized in retinal pigment epithelium, to be expressed in normal human epidermis. RPE65 is suspected to be involved in cellular uptake of retinol which is transported in the bloodstream complexed with plasma retinol-binding protein. OBJECTIVES: To evaluate protein and mRNA expression of RPE65 in actinic keratosis (AK), squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) compared with normal skin. METHODS: RPE65 mRNA expression in skin tumours relative to normal skin of the respective donor was studied by real-time polymerase chain reaction in AK (n = 15), invasive SCC (n = 30) and BCC (n = 18). A peptide-specific anti-RPE65 antibody was used for immunohistochemical staining of formalin-fixed and paraffin-embedded tissue sections of the respective tumours. RESULTS: RPE65 mRNA expression was reduced in AK. A highly significant reduction of RPE65 mRNA was observed in invasive SCC relative to normal skin of the respective donors. Immunohistochemistry revealed a continuous staining of basal and suprabasal keratinocytes in normal human epidermis. RPE65 in AK shown by immunohistochemical staining was reduced and quite irregular, whereas invasive SCC revealed no staining of tumour cells with the anti-RPE65 antibody. RPE65 mRNA values were elevated, whereas immunohistochemical staining for RPE65 protein was heterogeneous in BCC. CONCLUSIONS: These results suggest progressive downregulation of RPE65 from AK to invasive SCC.