Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04637 (p53)
 77,613 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The p53 gene (TP53) is mutated in numerous human cancers. We have used it as a molecular target to characterize the induction of mutations in human skin cancers. About 50% of all skin cancers in normal individuals exhibit p53 mutations. This frequency rises to 90% in skin cancers of patients with the DNA-repair deficiency known as xeroderma pigmentosum (XP). These mutations are characterized by a specific signature, attributed to the ultraviolet uvB part of the solar spectrum. In this review, we will describe different p53 mutation spectra, in relation to the various histopathological types of skin cancers such as basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and malignant melanoma as well as to the DNA repair efficiency of the patients. In particular, different mutational hot spots are found among the various spectra. We have tried to elucidate them in terms of induced DNA lesion hot spots, as well as speed of local nucleotide excision repair (NER) or sequence effects. The molecular analysis of these mutagenic characteristics should help in the understanding of the origin of human skin cancers in the general population.
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PMID:TP53 mutations in human skin cancers. 1261 7

Calpain, also named CAPN (for calcium-activated neutral protease), is a ubiquitous intracellular cytoplasmic non-lysosomal cysteine endopeptidase that requires calcium ions to exert its activity. Two major isoenzymes are known- micro -calpain (CAPN1) and m-calpain (CAPN2)-requiring micromolar and millimolar calcium concentrations for activation, respectively. Many known substrates of the different calpain isoenzymes, such as the transcription factors c-Fos and c-Jun, the tumour suppressor protein p53, protein kinase C, pp60src, or the adhesion molecule integrin, have been implicated in the pathogenesis of various malignancies including squamous (SCC) and basal (BCC) cell carcinomas of human skin, suggesting an important role of the calpain isoenzymes in malignant diseases. We have analysed the expression of CAP1 and CAPN2 protein and mRNA expression in BCCs and SCCs of human skin. Interestingly, CAPN1 immunoreactivity (streptavidin-peroxidase technique) was markedly reduced in BCCs compared to normal human skin or SCCs, while in contrast CAPN1 mRNA levels (determined by real-time PCR) were markedly elevated in BCCs and SCCs compared to normal human skin. No differences were found analysing CAPN2 protein and mRNA expression in normal human skin, BCCs and SCCs. In conclusion, we have demonstrated for the first time alterations in calpain mRNA expression and protein content in malignant skin tumours that may be of importance for the tumorigenesis and growth characteristics of BCCs and SCCs. However, our results do not allow conclusions on the function of CAPN1 and CAPN2 in BCCs and SCCs. It is not known if the CAPN genes in BCCs or SCCs exhibit functionally inactivating mutations or whether decreased CAPN1 protein expression in BCCs and elevated CAPN1 mRNA in BCCs and SCCs reflect a feedback loop coupled with increased degradation or proteolysis of CAPN1 protein.
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PMID:Different expression patterns of calpain isozymes 1 and 2 (CAPN1 and 2) in squamous cell carcinomas (SCC) and basal cell carcinomas (BCC) of human skin. 1263 42

There are over 1 million cases of skin cancer diagnosed yearly in the United States. The majority of these are nonmelanoma (NMSCs) and are associated with chronic exposure to ultraviolet light (UV). Actinic keratosis (AK) has been identified as a precursor for SCC, but not for BCC. AKs are far more common than SCC, making them excellent targets for chemoprevention. Cancer chemoprevention can prevent or delay the occurrence of cancer in high-risk populations using dietary or chemical interventions. We have developed strategies that have rational mechanisms of action and demonstrate activity in preclinical models of skin cancer. Promising agents proceed to phase I-III trials in subjects at high risk of skin cancer. UV light induces molecular signaling pathways and results in specific genetic alterations (i.e., mutation of p53) that are likely critical to skin cancer development. UVB-induced changes serve as a basis for the development of novel agents. Targets include inhibition of polyamine or prostaglandin synthesis, specific retinoid receptors, and components of the Ras and MAP kinase signaling pathways. Agents under study include: epigallocatechin gallate (EGCG), a green tea catechin with antioxidant and sunscreen activity, as well as UVB signal transduction blocking activity; perillyl alcohol, a monoterpene derived from citrus peel that inhibits Ras farnesylation; difluoromethylornithine (DFMO), an inhibitor of ornithine decarboxylase and polyamines; retinoids that target retinoid X receptors and AP-1 activity; and nonsteroidal anti-inflammatory agents that inhibit cylooxygenase and prostaglandin synthesis. We performed a series of Phase I-II trials in subjects with multiple AK. For example, a phase II randomized trial of topical DFMO reduced AK number, suppressed polyamines, and reduced p53 protein. Our goal is to develop agents for use in combination and/or incorporation into sunscreens to improve chemoprevention efficacy and reduce skin cancer incidence.
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PMID:Skin cancer chemoprevention: strategies to save our skin. 1290 51

We report a new case of sarcomatoid carcinoma, which showed cellular features of basal cell carcinoma and malignant fibrous myxoid histiocytoma. For this new case and rare neoplasm, we propose the designation of sarcomatoid basal cell carcinoma, as both components were intimately intermingled, the spindle cells seemed to arise from epithelial cells, and both tumoral components showed the same immunohistochemistry expression, cytokeratin and P53 protein, suggesting a monoclonal origin. The epithelial component, a basal cell carcinoma, may have been the first component in the carcinogenesis process.
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PMID:Basal cell carcinoma with sarcomatoid features (sarcomatoid carcinoma): report of a case and review of the literature. 1518 34

The p53-regulated 14-3-3sigma gene encodes an inhibitor of cell cycle progression essential for senescence and clonal evolution of keratinocytes in vitro. Here we analysed the in vivo expression of 14-3-3sigma protein in several skin diseases, which are characterized by hyperproliferative keratinocytes. Unexpectedly, the 14-3-3sigma protein was expressed at high levels in psoriasis (11 of 11 patients), condylomata acuminata (11/11), actinic keratoses (11/11) and squamous cell carcinomas (SCC) (11/11). However, keratinocytes that had undergone transformation to basal cell carcinoma (BCC) showed partial (10 of 41; 24.4%) or complete (19 of 41; 46.3%) loss of 14-3-3sigma protein expression. BCC (5/5), SCC (6/6) and actinic keratoses (7/7) concomitantly expressed the p53-homolog p63 and 14-3-3sigma at high levels, ruling out potential inhibitory effects of p63 isoforms on 14-3-3sigma transcription as the basis for loss of 14-3-3sigma expression. Of 41 BCC samples isolated by laser-capture microdissection, 28 (68.3%) showed CpG-hypermethylation of the 14-3-3sigma promoter combined with reduced or absent 14-3-3sigma protein levels in 22 cases (78.6%). Since it has been reported that BCC retain wild-type p16(INK4A) and here BCC with CpG-methylation of 14-3-3sigma did not show CpG-methylation of p16(INK4A) (0/17), silencing of 14-3-3sigma may contribute to evasion of senescence in BCC. As experimental removal of 14-3-3sigma sensitizes to DNA damage, silencing of 14-3-3sigma may explain the high efficacy of radiation therapy in the treatment of BCC.
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PMID:Analysis of 14-3-3sigma expression in hyperproliferative skin diseases reveals selective loss associated with CpG-methylation in basal cell carcinoma. 1293 12

Basal cell carcinoma (BCC) of the skin is the most common tumor in the white population. A 66-year-old man developed 2 BCCs at the left parietal region of the head and at the helix of the left ear. The 2 lesions matched exactly when pressing the ear against the head, suggesting an implantation metastasis mechanism. Molecular genetic techniques were used to confirm or exclude such a mechanism in this rare clinical constellation. Tumor tissues were precisely microdissected for DNA isolation. Exons 5-9 of the p53 tumor suppressor gene were directly sequenced. In addition, loss of heterozygosity analysis of chromosome 9q was performed using 5 polymorphic microsatellite markers. The BCC of the ear revealed a p53 mutation at codon 273, whereas the other one lacked this mutation. In addition, the smaller BCC of the ear showed loss of heterozygosity at 9q33.3, in contrast with the larger BCC. Interestingly, histologically normal skin of the ear distant from the small BCC had the same deletion, indicating a field defect of this skin patch at 9q33.3. Molecular genetic analysis clearly demonstrated different genetic alterations of the two BCCs and therefore most likely excludes a mechanism of implantation metastasis.
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PMID:Molecular genetic analysis excludes implantation metastasis of basal cell carcinomas. 1294 16

To distinguish the infiltrative from the non-infiltrative basal cell carcinoma (BCC), cell cycle markers are being used to supplement histopathological assessment, and proliferation markers are proving particularly useful. A successful radical therapeutic intervention depends on a clear histopathological diagnosis, especially for the tumour margins. For this purpose we investigated whether proof of telomerase activation is a suitable adjunctive molecular marker. We were also interested in the telomerase activity (TA) of BCC-free margin tissues as a prognostic parameter of relapse. Using PCR-ELISA kits, we found TA in 26/30 (87%) BCC tissues and in 8/25 (32%) of the tumour-free surgical margin tissues. Telomerase levels and the incidence of telomerase-positive tumour tissues are not always associated with positive p53 immunoreactive scores in BCC tissues. But telomerase levels correlate significantly with p53 expression levels. In the Kaplan-Meier curve, patients with telomerase-positive tumour-free surgical margin tissues showed significantly shorter relapse-free periods than patients with telomerase-negative tumour-free margin tissues.
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PMID:Clinical significance of telomerase activity in basal cell carcinomas and in tumour-free surgical margins. 1453 81

Keloids are benign mesenchymal tumours, usually present at and extending beyond the margins of sites of previous injury. It is reported that keloids display aberrant expression of apoptotic genes: TGFB1 is activated, whereas caspase 8 and 3 are not, thus indicating a block upstream in the apoptosis cascade in keloids. Interferon-alpha 2b normalizes the excessive synthesis of collagen, glycosaminoglycans and collagenase by keloidal fibroblasts, reduces recurrences following keloid excision, and enhances the expression of native p53 and apoptosis. Imiquimod, a rapid and potent inducer of interferons locally at the site of application to the skin, reduces recurrences following keloid excision and alters gene expression of markers of apoptosis in basal cell carcinoma cells. We investigated the effects with respect to the expression of apoptotic genes in keloidal tissue compared with nontreated controls of imiquimod 5% cream applied topically to keloids. Total RNA was extracted from excised keloidal tissue, cDNA probes synthesized and then hybridized to gene-specific cDNA fragments spotted on membranes. The expression levels of 96 genes involved in apoptosis, relative to cyclophilin expression, were compared in the imiquimod-treated and untreated groups. The mean ratio of expression, relative to cyclophilin of caspase 3 and DFFA were significantly enhanced. Caspase 3 was significantly downregulated and DFFA was significantly upregulated in the group of imiquimod-treated keloids (P < 0.05) compared with the untreated group of keloids. Although imiquimod is capable of altering the expression of these markers of apoptosis in keloids, their role, if any, in the therapeutic response of keloids to imiquimod requires further investigation.
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PMID:Topical application of imiquimod 5% cream to keloids alters expression genes associated with apoptosis. 1461 55

The malignant tumours of the lip account for nearly 1-2% of the cervicofacial neoplasms. These lesions are frequently spinous cell carcinomas and basal cell carcinomas (25% of all oral cancers). The spinous cell carcinoma is mainly located in the lower lip, the basal cell carcinoma is more common in the upper lip. The incidence of lip cancer in males is much high than in females. The etiopathogenesis of these lesions is connected with exposure to sun, smoking, genetics predisposition (mutation of the p53 suppressor factor) and with the evolution of precancerous lesions (radiodermatitis, chronic cheilitis, xeroderma pigmentosum). Some Authors emphasized the viral etiopathogenesis: HPV16, HPV24, HSV1, HSV2. The treatment of lip carcinoma is surgical: excision and reconstruction. The numerous reconstructive techniques are mostly the cutaneous local sliding flaps and the rotation flaps. The lip reconstruction require a remarkable diligence for preserve, as much possible, the shape and functions of lip. The Authors report their experience about the surgical treatment of 19 patients with lip carcinoma (16 spinous cell carcinomas, 3 basal cell carcinomas) and describe the main surgical reconstructive techniques to preserve the feeding, phonation and mimic expression.
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PMID:[Surgical treatment of malignant lip tumors. Personal experience]. 1472 93

Cancers of the skin encompass the first and second most common neoplasms in the United States, epidermal basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), respectively, as well as the melanocytic malignancy, malignant melanoma (MM). Recently identified alterations in the function of specific genes in these cancers provide new potential therapeutic targets. These alterations affect conserved regulators of cellular proliferation and viability, including the Sonic Hedgehog, Ras/Raf, ARF/p53, p16(INK4A)/CDK4/Rb and NF-kappaB pathways. New modalities designed to target these specific proteins may represent promising approaches to therapy of human skin cancers.
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PMID:Targets for molecular therapy of skin cancer. 1475 36


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