朗格汉斯细胞组织细胞增生症中TP53蛋白表达及基因突变检测

目的检测朗格汉斯细胞组织细胞增生症(LCH)中TP53蛋白表达和TP53基因全外显子突变,以探讨TP53在LCH发生发展中的作用机制。方法应用免疫组化SP法检测38例LCH中TP53蛋白水平;对16例TP53蛋白阳性组织原位提取DNA后PCR直接测序检测TP53基因外显子2～11的变化。结果 38例LCH样本TP53蛋白阳性16例(42.11%)。在16例阳性的平均吸光度比较中,分别为10例广泛型(MS)(0.1206±0.0088),6例局限型(SS)(0.1221±0.0030),二者表达差异无统计学意义(P>0.05)。PCR直接测序16例阳性LCH,2～11号外显子突变未见异常。TP53codon72基因型频率为:LCH组PRO型3例,ARG型5例,PRO/ARG型8例;与40例正常对照相比较分布差异无统计学意义(P>0.05)。LCH组中MS组PRO型2例,ARG型3例,PRO/ARG型5例;SS组PRO型1例,ARG型2例,PRO/ARG型3例。两组频率分布差异无统计学意义(P>0.05)。结论 LCH中有朗格汉斯细胞组织细胞TP53蛋白异常表达,但在临床分型上比较差异无统计学意义;LCH中TP53基因在全外显子无突变。TP53codon72基因型与正常人群一致且与临床分型及预后无相关。在LCH中可能有另一无关基因突变的机制影响了TP53蛋白表达。     

Spiradenocarcinoma with low-grade basal cell adenocarcinoma pattern: report of a case with varied morphology and wild type TP53

We present a patient with a 2-cm spiradenocarcinoma of the left arm resembling low-grade salivary gland basal cell adenocarcinoma. In addition to showing attributes of conventional spiradenoma, the benign component showed prominent areas of cystic change with focal apocrine differentiation, glands with and without mucinous differentiation, clear cell change and focal adenoid cystic carcinoma-like areas. The malignant component was composed of nodules of basaloid cells arranged in sheets with variable tendency to luminal differentiation. The nuclear atypia was low-grade, and the mitotic index was high in the malignant component (to 8/10 high power fields). Immunohistochemically, there was diffuse but variable positivity for cytokeratin 7 in both the benign and malignant components. Epithelial membrane antigen was focally positive, highlighting cells with ductal (luminal) differentiation. Expression of p63 was observed in 50 and 80% of the cells in the benign and malignant components, respectively. Calponin was negative. The proliferative index (MIB-1/Ki-67) was <3% in the benign component and up to 10% in the malignant component. Although the malignant component displayed patchy areas with nuclear p53 immunoreactivity with variable intensity, no mutation in the TP53 gene was identified.     

Somatic mutations in the PTCH, SMOH, SUFUH and TP53 genes in sporadic basal cell carcinomas

BACKGROUND: Basal cell carcinoma (BCC) of the skin is the most common human cancer. The genetic alterations underlying BCC development are only partly understood. OBJECTIVES: To investigate further the molecular genetics of sporadic BCCs, we performed mutation analyses of 10 skin cancer-associated genes in 42 tumours. METHODS: Single-strand conformational polymorphism analysis followed by DNA sequencing was used to screen for mutations in the sonic hedgehog pathway genes PTCH, SMOH, SUFUH and GLI1, in the TP53 tumour suppressor gene, and in the proto-oncogenes NRAS, KRAS, HRAS, BRAF and CTNNB1. Microsatellite markers flanking the PTCH, SUFUH and TP53 loci at 9q22, 10q24 and 17p13, respectively, were studied for loss of heterozygosity (LOH). RESULTS: PTCH mutations were found in 28 of 42 tumours (67%). Microsatellite analysis revealed LOH on 9q22 in 20 of 38 tumours investigated (53%), including 14 tumours with and six tumours without PTCH mutations. SMOH mutations were identified in four of the 42 BCCs (10%) while two tumours demonstrated mutations in SUFUH, including one missense mutation and one silent mutation. None of the BCCs showed LOH at markers flanking the SUFUH locus. Seventeen BCCs (40%) carried TP53 mutations, with only three tumours showing evidence of biallelic TP53 inactivation. TP53 mutations were present in BCCs with and without mutations in PTCH, SMOH or SUFUH. Interestingly, 72% of the TP53 alterations were presumably ultraviolet (UV)-induced transition mutations. In contrast, only 40% of the PTCH and SMOH alterations corresponded to UV signature mutations. No mutations were identified in GLI1, NRAS, KRAS, HRAS, BRAF or CTNNB1. CONCLUSIONS: Our data confirm the importance of PTCH, SMOH and TP53 mutations in the pathogenesis of sporadic BCCs. SUFUH alterations are restricted to individual cases while the other investigated genes do not appear to be important targets for mutations in BCCs.     

变性梯度凝胶电泳和单链构象多态性分析检测皮肤癌p16、p53基因突变

目的：探讨p16、p53基因突变在皮肤癌发生中的作用并比较变性梯度凝胶电泳(DGGE)和单链构象多态性分析(SSCP)检测基因突变的敏感性。方法：分别采用聚合酶链反应(PCR)-DEEG和PCR—SSCP，对40例皮肤癌患者手术切除组织的p16基因1、2外显子和p53基因5～8外显子进行突变检测。结果：仅2例鳞状细胞癌(SCC)出现p16基因外显子2突变，皮肤癌p16基因1、2外显子的突变率为5％。p53基因5—8外显子的突变率为35％，其中SCC的突变率为36％，基底细胞癌(BCC)为33％，采用DGGE检测的突变率为33％，SSCP检测的突变率为25％。结论：p16、p53基因突变参与皮肤癌的发病机制；p16基因的突变率低于p53基因；DGGE检测基因突变的敏感性高于SSCP；DGGE结合SSCP有助于提高突变检出率。     

Next-generation sequencing revealing TP53 mutation as potential genetic driver in dermal deep-seated melanoma arising in giant congenital nevus in adult patients: A unique case report and review of the literature

Melanoma in giant congenital nevus (M-GCN) is a rare and potentially lethal neoplasm. In children, M-GCN appears as a dermal/deep-seated melanoma (DDM-GCN) with histopathologic features difficult to distinguish from proliferative nodules (PNs-GCN). DDM-GCN in adults is an anecdotal entity and only 8 cases have been described and genetically characterized. We report the first case of DDM-GCN in a 34-year-old man characterized with a large-panel next-generation sequence (NGS) highlighting a TP53 mutation with a UV-signature (C>T substitution) in DDM but not in PNs-GCN and GCN. Curiously, DDM showed an aberrant p16 overexpression without detection of CDKN2A mutation at NGS. In line with previous studies, it supports a different pathway in children and adults: UV-induced mutations may be involved in the latter not only by CDKN2A but also by TP53 mutations, with a potentially confusing overexpression of p16 protein. While these data need to be confirmed in larger cases series, our results show that NGS could be an additional genetic diagnostic tool in DDM-GCN.     

p53 gene mutations in human skin cancers

Abstract: The p53 gene is mutated in numerous human cancers. We used it as a molecular target to characterize and try to understand the induction of mutations in human skin cancers. About 40–50% of all skin cancers in normal individuals and 60–80% of the DNA-repair-deficient xeroderma pigmentosum patients exhibit p53 mutations. Among these tumors, the melanomas are the less mutated ones. These mutations are characterized by specific signatures believed to be due to the UVB part of the solar spectrum. Different mutation spectra and different hot spots of mutations are found according to histopathological types of skin cancer. These data are interpreted in term of hot spots for DNA lesion induction, speed of local repair or sequence effects. The molecular analysis of these mutagenic characteristics should help us to understand the origin of human skin cancers in the general population.     

Multiple genetic copy number alterations in oral squamous cell carcinoma: study of MYC,TP53, CCDN1, EGFR and ERBB2 status in primary and metastatic tumours

Background Oncogenesis in the oral cavity is believed to result from genetic alterations that cause a stepwise transformation of the mucosa to invasive carcinoma. In oral squamous cell carcinoma (OSCC) multiple cytogenetic abnormalities have been reported, but their practical significance remains uncertain. Objective To evaluate the usefulness of the assessment of CCND1, MYC, EGFR, ERBB2 and TP53 in OSCC and lymph node metastases. Methods Fifty‐one consecutive samples of OSCC, nine lymph node biopsies showing metastatic spread from OSCC, 16 biopsies diagnosed as oral leucoplakia (OLK), 13 samples corresponding to oral lichen planus (OLP) and 14 samples from normal oral mucosa were included in the study. Clinical and histopathological characteristics were reviewed. The genetic and protein status of the CCND1, MYC, EGFR, ERBB2 oncogenes and the TP53 tumour suppressor gene were assessed by fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC). The obtained results were compared with the clinical characteristics and the outcome of the OSCCs. Results TP53 gene losses and MYC, ERBB2, CCND1 and EGFR copy number gains and amplifications were detected in a higher proportion in OSCC and lymph node samples than in OLK and OLP samples (P < 0·005). Overexpression of p53, Myc, Cyclin D1, c‐erbB‐2 and epidermal growth factor receptor (EGFR) was more prevalent in malignant samples than benign samples (P < 0·05). Correlation between FISH and IHC results was demonstrated in MYC, EGFR and CCND1 studies. The presence of two or more genetic abnormalities in the studied loci was exclusively detected in primary and metastatic OSCC. Conclusions In our series, genetic abnormalities in TP53, MYC, CCND1, ERBB2 and EGFR detected by FISH were absent in inflammatory lesions, infrequent in precursor lesions and common in tumoral lesions. Evaluation of the genetic status of TP53, MYC, CCND1, ERBB2 and EGFR may be an additional diagnostic tool in distinguishing benign from malignant oral lesions in histopathologically challenging cases.     

Cutaneous pleomorphic fibromas arising in patients with germline TP53 mutations

Pleomorphic fibromas are rare benign cutaneous neoplasms associated with deletion/loss of chromosomes 13q and 17p, where RB1 and TP53 are located, respectively. Herein, we report five cases of pleomorphic fibroma arising in patients with germline TP53 mutations, suggesting a potential link with Li-Fraumeni syndrome. All three patients were female and young (mean age 27) with a strong personal and/or family oncologic history and confirmed pathogenic germline TP53 mutations. In two patients, multiple pleomorphic fibromas were diagnosed. Clinically, the lesions arose at various cutaneous sites and were small (≤2 cm) and raised (4/5). Histopathologically, the tumors were paucicellular, composed of atypical spindled to stellate cells with hyperchromatic and variably pleomorphic nuclei. Mitotic activity was exceedingly low, although rare atypical mitotic figures were seen in one case. Immunohistochemically, the tumor cells were diffusely positive for p16 (3/3) and showed loss of Rb expression (5/5). All cases showed aberrant p53 expression (overexpression in 4, complete loss in 1). The tumors have followed a benign clinical course with no evidence of progression or recurrence. In conclusion, the development of multiple pleomorphic fibromas in a young patient may be a clue to an underlying genetic cancer syndrome involving TP53.     

The Association Between TP53 Arg72pro Polymorphism and Non-Melanoma Skin Cancer Risk: A Meta-Analysis Including 7,107 Subjects

Background:

The p53 gene is a critical molecular in the protection of cells from DNA damage due to Ultraviolet (UV) exposure, and TP53 mutation is very common in non-melanoma skin cancer.

Objectives:

To assess the association between the TP53 Arg72Pro polymorphism and non-melanoma skin cancer (NMSC) risk.

Methods:

We performed this meta–analysis with 13 case-control studies involving 3,520 cases and 3,587 controls.

Results:

Our meta-analysis showed that TP53 Arg72Pro polymorphism was not associated with non-melanoma skin cancer susceptibility in overall population.(for Arg/Arg vs. Pro/Pro: OR 0.98, 95% CI 0.80-1.19; for Arg/Pro vs. Pro/Pro: OR 0.99, 95% CI 0.84-1.17; for the recessive model Arg/Arg vs. Arg/Pro + Pro/Pro: OR 1.10, 95% CI 0.89-1.35; for the dominant model Arg/Arg + Arg/Pro vs. Pro/Pro: OR 1.00, 95% CI 0.85-1.18). We also detected no effect of this polymorphism on any subtype of non-melanoma skin cancer, such as squamous cell carcinoma (SCC), and basal cell carcinoma (BCC). Furthermore, no significant association in any subgroup was detected in stratified analyses according to ethnicity. However, in the stratified analysis by sample collection resources, Arg/Arg carriers from tumor tissue subgroup had 3.42 times risk of cancer (95% CI, 1.19 to 9.84) as compared with the variant type Pro/Pro in NMSC.

Conclusions:

TP53 Arg72Pro polymorphism may have little involvement in the pathogenesis of NMSC, regardless of type, including SCC, and BCC.     

Cyclobutane pyrimidine dimer formation and p53 production in human skin after repeated UV irradiation

Substantial differences in DNA damage caused by a single UV irradiation were found in our previous study on skin with different levels of constitutive pigmentation. In this study, we assessed whether facultative pigmentation induced by repeated UV irradiation is photoprotective. Three sites on the backs of 21 healthy subjects with type II-III skin were irradiated at 100-600 J/m(2) every 2-7 days over a 4- to 5-week period. The three sites received different cumulative doses of UV (1900, 2900 or 4200 J/m(2)) and were biopsied 1 day after the last irradiation. Biomarkers examined included pigment content assessed by Fontana-Masson staining, melanocyte function by expression of melanocyte-specific markers, DNA damage as cyclobutane pyrimidine dimers (CPD), nuclear accumulation of p53, apoptosis determined by TUNEL assay, and levels of p21 and Ser46-phosphorylated p53. Increases in melanocyte function and density, and in levels of apoptosis were similar among the 3 study sites irradiated with different cumulative UV doses. Levels of CPD decreased while the number of p53-positive cells increased as the cumulative dose of UV increased. These results suggest that pigmentation induced in skin by repeated UV irradiation protects against subsequent UV-induced DNA damage but not as effectively as constitutive pigmentation.     

Immunophenotypic analysis of the p53 gene in non-melanoma skin cancer and correlation with apoptosis and cell proliferation

BACKGROUND: Sunlight precipitates a series of genetic events that lead to the development of skin cancers such as basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). The p53 tumour suppressor gene, which plays a pivotal role in cell division and apoptosis, is frequently found mutated in sunlight-induced skin tumours. OBJECTIVE: To investigate the immunoreactivity of the p53 gene in non-melanoma skin cancers and to correlate its expression with apoptotic and cell proliferation markers. METHODS: We analysed 35 non-melanoma tumours including 19 BCCs and 16 SCCs from sun-exposed skin areas. p53 protein expression was studied immunohistochemically using the DO7 monoclonal antibody against wild-type and mutant p53 forms. The percentage of p53-immunopositive nuclei was measured by image analysis. Cell proliferation and apoptosis were also assessed by image analysis following Ki-67 immunostaining and application of the TUNEL method on paraffin sections, respectively. RESULTS: The percentage of p53-expressing cells varied from 3.5 to 90 in BCCs (median value 54.4%) and from 3.7 to 94 in SCCs (median value 40.3%). The mean value of Ki-67-positive cells was comparable in both groups of tumours with a mean value of 40.6% in BCCs and 34.6% in SCCs. Conversely, the TUNEL assay showed sporadic staining of apoptotic cells within the tumours with a mean value of 1.12% in BCCs and 1.8% in SCCs. p53 protein expression was correlated positively with cell proliferation (r = 0.75, P = 0.000001) and negatively with apoptosis (r = -0.23, P = 0.05). CONCLUSION: p53 immunoreactivity was high in the majority of the skin carcinomas examined and correlated positively with cell proliferation and negatively with apoptosis. The p53 protein overexpression appears to be related to an inactivated protein resulting from mutations of the p53 gene or other unclear molecular mechanisms.     

EGCG对中波紫外线诱导HaCaT细胞p53基因和蛋白表达的实验研究

目的:研究表没食子儿茶素没食子酸酯(EGCG)对中波紫外线(UVB)照射诱导永生化角质形成细胞株-HaCaT细胞的p53 mRNA和p53蛋白表达的影响。方法:以一定剂量UVB照射HaCaT细胞,并以200μg/mL EGCG处理照射后的HaCaT细胞,分别用RT-PCR法和Western blot方法检测各处理条件下p53 mRNA和/或p53蛋白的表达水平。结果:30 mJ/cm2的UVB照射后HaCaT细胞的p53 mR-NA和p53蛋白表达逐渐增加,4 h达到峰值,4 h后随照射剂量增加而增加,24 h后有所恢复;加入EGCG可下调UVB诱导的表达作用。结论:UVB照射对HaCaT细胞p53 mRNA和p53蛋白的诱导表达有时效性与量效性,EGCG可下调UVB照射的这种诱导作用。     

Hay‐Wells syndrome in a child with mutation in the TP73L gene

Hay‐Wells syndrome is a rare form of ectodermal dysplasia, also known as AEC syndrome (Ankyloblepharon filiforme adnatum, Ectodermal effects, Cleft lip/palate). It is inherited in an autosomal dominant fashion with variable expression, featuring congenital abnormalities of skin, hair, teeth, nail, eccrine and mucous glands. We present a three‐month‐old boy, born to unaffected parents, with typical clinical findings of AEC syndrome. In this boy, a mutation Ile537Thr (c.1610C>T) in the sterile alpha motive (SAM) domain of the TP73L (p63) gene was detected. Because of the broad spectrum of related syndromes such as Rapp‐Hodgkin syndrome, Bowen‐Armstrong syndrome, CHAND syndrome and epidermolysis bullosa hereditaria, the diagnosis of AEC should be base don both clinical findings and genetic analysis.     

p53基因沉默对HaCaT细胞MicroRNA表达谱的影响

目的 研究p53基因沉默前后HaCaT细胞microRNA（miRNA）的差异表达谱并进行相关功能分析。方法 利用慢病毒介导的RNAi对培养的HaCaT细胞株进行p53基因沉默,通过Trizol法抽提细胞总RNA,PEG（聚乙二醇）方法分离miRNA,T4RNA连接酶荧光标记后进行miRNA芯片杂交,利用Genepix 4000B 图像分析软件和Genepix Pro 6.0软件进行数据分析,生物信息学方法检索出p53基因沉默前后HaCaT细胞差异表达的miRNA调控的靶基因,选取每个miRNA调控的前20个靶基因进行靶基因功能及KEGG分析。结果 p53基因沉默前后HaCaT细胞中发现53个差异表达的miRNA,其中41个表达上调,12个下调（差异 ＞ 2倍）。上调超过200倍的miRNA有：hsa-miR-141-3p、hsa-miR-15a-5p、hsa-miR-27a-3p、hsa-miR-130b-3p、hsa-miR-19a-3p;下调超过75%的miRNA有：hiv1-miR-TAR-3p、hsa-miR-630、hsa-miR-1246、hsa-miR-1275。靶基因预测和靶基因KEGG分析结果显示,部分靶基因与MAPK信号通路、代谢通路、肿瘤侵袭等有关。结论 hsa-miR-141-3p等9个miRNA及其调控的靶基因可能参与p53的分子调控。 【关键词】 基因,p53; 角蛋白细胞; 微RNAs; 基因沉默; 芯片分析技术     

TP53 and ATM mRNA expression in skin and skeletal muscle after low-level laser exposure

Low-level lasers are widespread in regenerative medicine, but the molecular mechanisms involved in their biological effects are not fully understood, particularly those on DNA stability. Therefore, this study aimed to investigate mRNA expression of genes related to DNA genomic stability in skin and skeletal muscle tissue from Wistar rats exposed to low-level red and infrared lasers. For this, TP53 (Tumor Protein 53) and ATM (Ataxia Telangiectasia Mutated gene) mRNA expressions were evaluated by real-time quantitative PCR (RT-qPCR) technique 24 hours after low-level red and infrared laser exposure. Our data showed that relative TP53 mRNA expression was not significantly altered in both tissues exposed to lasers. For ATM, relative mRNA expression in skin tissue was not significantly altered, but in muscle tissue, laser exposure increased relative ATM mRNA expression. Low-level red and infrared laser radiations alter ATM mRNA expression related to DNA stability in skeletal muscle tissue.     

p53在2例良性皮肤病恶变过程中的表达及临床意义探讨

以ＤＯ－１鼠单克隆抗体进行免疫组化染色，检测２例患者从良性病变发展为恶性肿瘤过程中不同皮损的ｐ５３表达。结果良性损害为ｐ５３阴性，继发癌前期损害和恶性肿瘤则ｐ５３表达阳性，提示ｐ５３突变可能参与了表皮恶性肿瘤的发生和演变。