Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0596263 (carcinogenesis)
 64,820 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lung cancer is the most common cause of cancer death in Japanese males, the incidence having increased markedly in recent years. Carcinogen exposure such as to tobacco-smoke and air pollution are associated with the probability of developing lung cancer. Aquired somatic mutations play an important role in the pathogenesis of environmentally induced lung cancers. Cytogenetic and molecular analysis of lung tumors has made it possible to examine this hypothesis and to search for candidate genes that may be targeted by chronic exposure to these carcinogens. Early studies implicate several distinct chromosomal loci (3p, 9p, 13q, 17p, and others) and suggest sequential genetic events occur during the initiation and progression of lung carcinogenesis. Several suppressor genes including Rb (13q), P53 (17p), and P16 (9p) have been identified and cloned at these chromosomal loci. The identification of putative tumor suppressor gene at chromosome 3p is still under work. Understanding the interaction of P53, RB, cyclins, and protein kinase inhibitors including P16 will be essential to the development of the next generation of diagnostic and therapeutic studies for lung cancer.
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PMID:Tumor suppressor genes in human lung cancer. 939 13

The fish genus Xiphophorus provides a vertebrate model useful in etiological studies of cancer. Hybrid fish can spontaneously develop melanomas deriving from the inheritance of melanistic pigment patterns and the simultaneous absence of proper genetic regulation. A cyclin-dependent kinase inhibitor gene, termed CDKN2X, was mapped to a genomic region that is implicated in fish melanoma tumor suppression. The related human tumor suppressor locus CDKN2A (P16, INK4A, MTS1) is deleted, mutated or transcriptionally repressed through methylation of cytosine bases within the 5' CpG island in a variety of neoplasms, including melanoma. The fish CDKN2X locus harbors a CpG island within its promoter and first exon, analogous in location to CpG islands in human CDKN2A and CDKN2B loci. The methylation state of individual CpG dinucleotides was investigated in genomic DNA derived from control tissues and melanomas within the CDKN2X 5' CpG island. The studied genomic area was found to be virtually unmethylated in all tested tissues including melanomas. In addition, RNA expression studies of the fish CDKN2X locus revealed that it is significantly overexpressed in melanoma, in contrast to what has been reported for the human CDKN2A locus in melanoma. Such overexpression may be a consequence of the pronounced upregulation of the Xmrk-2 receptor tyrosine kinase oncogene reported in several Xiphophorus melanoma models.
Carcinogenesis 2000 Apr
PMID:Overexpression of a fish CDKN2 gene in a hereditary melanoma model. 1075 92

We observed the relationship between p16 gene and the occurrence, development and prognosis of carcinoma of nasopharynx by means of LSAB immunohistochemistry method and investigated the expression of protein P16 in 73 cases of carcinoma of nasopharynx and 10 cases of epithelia of chronic inflammation of nasopharynx. The results showed that P16 positive rate was 100% for the epithelia of chronic inflammation of nasopharynx. It was significantly higher than the P16 positive rate for the carcinoma of nasopharynx (38.4%, P < 0.01). There was significant difference of P16 positive expression in differentiation of nasopharyngeal carcinoma (poor differentiation versus undifferentiation), clinical staging (I-II versus IV) and grading of tumor (T1-T2 versus T3, T4) (P < 0.01). There was no correlation between P16 expression and metastatic lymph node (P > 0.05). The 3-year survival rates were 88.9% and 72.9% in P16 expression (+) and (-) patients respectively (P < 0.05). These findings suggested that P16 might play an important role in the process of carcinogenesis and development of nasopharyngeal carcinoma, and P16 might be used as a valuable marker for assessment of the biological behavior and prognosis of nasopharyngeal carcinoma.
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PMID:[Relationship between expression of P16 protein and prognosis in carcinoma of nasopharynx]. 1138 49

All authors integrating the known facts into a model of thyroid carcinogenesis concur that two main histotypes of thyroid cancer exhibit different routes of molecular development. RET rearrangements are an initiating event in papillary carcinoma, and simultaneously the most characteristic mutation for this type of cancer. They are followed by further, not well recognized, mutations. RAS mutations are regarded as a crucial event in the development of follicular tumors already at the adenoma step, while in papillary cancer they belong to the spectrum of secondary mutations, enabling tumor progression. Aberrant DNA methylation, causing loss of P16 tumor supressor gene, may be a common event in both types of cancer. Aneuploidy is seen much more frequently in follicular than in papillary cancer, which also exhibits a low rate for loss of heterozygosity and microsatellite instability. Mutations of the P53 tumor supressor gene are a common feature of undifferentiated thyroid cancers and could be responsible for their aggressive phenotype. RET rearrangements have been proposed as identifying fingerprints for irradiation induced thyroid cancer in children. Our own data speak against this hypothesis. We noted a high frequency of RET/PTC3 mutations in a group of Polish children with papillary thyroid carcinoma, regarded as sporadic cancer.
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PMID:Molecular changes in thyroid neoplasia. 1182 Jun 15

The p16(INK4A-ARF) locus plays a crucial role in the control of cellular proliferation via both the Rb and P53 pathways. We previously demonstrated that this locus is altered in human skin carcinomas. In the present study we have studied the expression of the p16(INK4A-ARF) locus following UVB irradiation of normal human keratinocytes both at the mRNA (RT-PCR) and at the protein (Western blotting) levels. Our data confirmed that P16(INK4A) protein is induced by UVB at low (30 mJ cm(2)) and high (100 mJ cm(2)) doses and is observed after a single or repeated exposure implying that this response is involved in both the immediate and adaptative response to UVB. The apparent absence of induction p16(INK4A) mRNA suggested that P16(INK4A) protein is upregulated at the post-transcriptional level. Analysis by flow cytometry and BrdU staining indicated that the highest protein level of P16(INK4A) in the cells was associated with a G(2) cell cycle arrest. Comparative analysis of P16(INK4A) and P53 showed that they were differentially modulated in keratinocytes according to the UVB dose and regimen. Low, acute or repeated UVB exposures led to accumulation of both P16(INK4A) and p53, whereas at high UVB doses, P53 and P53-dependent genes were not induced or even downregulated and only a slight but reproducible stabilization of P16(INK4A) protein was observed. In our conditions, P14(ARF) did not seem to participate in the UV response in these cells as P14(ARF) protein did not vary. These results infer that P16(INK4A) plays a role in cell cycle regulation of keratinocytes submitted to UVB irradiation. They also reinforce our previous demonstration of the importance of inactivation of this gene in UV-induced skin carcinogenesis.
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PMID:P16(INK4A) is implicated in both the immediate and adaptative response of human keratinocytes to UVB irradiation. 1196 38

P16 protein is a cell cycle regulator involved in the genesis of many types of tumors. In order to study the significance and expression of P16 protein in liver tissue of viral hepatitis, 48 patients with viral hepatitis and 7 cases with hepatocarcinoma were investigated by immunohistochemistry. The results showed that the positive rate of P16 protein expressed in the liver tissues of mild (85.0%) and moderate (91.66%) chronic viral hepatitis were significantly higher than that in liver cirrhosis and hepatocarcinoma (P < 0.01, 0.001), this suggest that the expression of P16 plays an important role in the carcinogenesis.
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PMID:[Study on expression of P16 protein in the liver tissue of viral hepatitis]. 1251 87

Energy restriction (ER) results in a profound inhibition of chemically induced mammary carcinogenesis. The cancer inhibitory activity of ER has been shown to be associated with lower rates of cell proliferation during both premalignant and malignant stages of this disease process. Moreover, inhibition of carcinogenesis and suppression of cell proliferation occur in animals in which plasma concentrations of insulin-like growth factor (IGF)-I are reduced, and plasma corticosterone levels are increased concomitantly. Given the role of both hormones in signal transduction pathways that can modulate cell cycle progression, albeit via different regulatory mechanisms, we report experiments conducted to determine whether hypothesized effects of changes in plasma levels of IGF-I and corticosterone on cell cycle regulation could be detected in mammary carcinomas occurring in 40% ER rats in comparison to ad libitum fed control rats or 40% ER rats that were energy repleted for 7 days (ER-REP). As determined by appropriate combinations of immunoprecipitations, Western blots, and kinase activity assays, it was found that levels of phosphorylated retinoblastoma and E2F-1 were significantly reduced by ER (approximately 40 and 75%, respectively; P < 0.01), an effect that was partially reversed by ER-REP. Reductions in cyclin-dependent kinase (CDK)2 (82%) and CDK4 (77%) kinase activity in ER carcinomas were likely to account for the observed effects on retinoblastoma and E2F-1. Both Cip1/p21 and Kip1/p27 and levels of these proteins complexed with CDK2 were significantly elevated in ER carcinomas (P < 0.01), and levels of cyclin E were reduced. On the other hand, regulation of CDK4 kinase activity by ER was likely attributable to effects on cyclin D1 as well as increased binding of P16 and P19 to CDK4. The majority of changes induced by ER were reversed by ER-REP. These observations are consistent with the hypothesis that ER exerts its profound cancer inhibitory activity, in part, by multifaceted regulation of cell cycle machinery, possibly via concomitant changes in corticosterone and IGF-1 metabolism, although the role of other hormones and growth factors should not be dismissed.
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PMID:Effect of energy restriction on cell cycle machinery in 1-methyl-1-nitrosourea-induced mammary carcinomas in rats. 1264 81

Ultraviolet (UV) radiation is a prevailing factor implicated in the etiology of keratinocytic intraepidermal neoplasia (KIN) and squamous cell carcinomas (SCCs), as evidenced by the high frequency of UV-related mutations in the p53 and p16 tumor suppressor genes. In renal transplant recipients (RTRs), immunosuppression is considered another important risk factor in the enhanced carcinogenesis in these patients. So far, effects of UV and immune status on p53 and p16 immunoexpression in SCCs and precursors have not been studied. The aims of this study were to assess (1) the relation between risk factors for carcinogenesis, sun exposure and immune status, and p16 or p53 expression, and (2) to assess differences in p16 and p53 expression between KINs and SCCs. Immunostaining for p16 and p53 was performed on paraffin-embedded sections of 23 low-grade KIN (LKIN) lesions, 28 high-grade KINs (HKINs), and 35 SCCs from 44 RTRs and 42 immunocompetent controls (ICIs). In 74/86 lesions (86%), p53 was expressed, and in 63/86 (76%) lesions, p16 expression was present. Negativity for both p16 and p53 was found in 4/86 (5%) cases, whereas combined p53/p16 staining was most prevalent (55/86 lesions, 64%). P16 staining proved independent of p53 expression (P =.8), and immune status, sun exposure, and histological diagnosis (LKIN-HKIN-SCC) had no influence on this independence. Transplantation was associated with p53 expression in SCCs (P =.02; power = 34%) caused by higher prevalence of p53-negative SCCs in RTRs than in ICIs (30% versus 0). In HKINs, p16 was more frequently positive than in LKINs (P =.003; power = 49%) and SCCs (P =.03; power = 53%). HKINs showed more frequent transepidermal p16 and p53 staining than LKIN lesions (P <.001; power >/= 99%). This study demonstrates that in KIN lesions and cutaneous SCCs, p16 expression is independent of p53 expression, and immune status, sun exposure, and histological diagnosis have no influence on this independence. Furthermore, HKIN lesions express significantly more p16 than LKINs and SCCs.
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PMID:P16 and p53 expression in (pre)malignant epidermal tumors of renal transplant recipients and immunocompetent individuals. 1367 50

The UVB component of the solar spectrum induces DNA lesions that, in the absence of error-free DNA repair, may give rise during DNA replication to mutations in caretaker and gatekeeper genes. The DNA repair genes are the best candidates for caretaker genes as exemplified by the human hereditary xeroderma pigmentosum (XP) syndrome. Cultured XP cells are hypermutable after UVB irradiation. This increased mutation frequency is also found in gatekeeper genes, which govern signalling pathways implicated in the control of cellular proliferation, differentiation and survival of human epidermal keratinocytes. We describe and discuss the role of mutated gatekeeper genes in five specific signalling pathways which have been implicated in skin carcinogenesis. The pathways we focus on in this review are: (i) P16(INK4A)-CDK4/6-RB; (ii) P14(ARF)-HDM2-P53; (iii) Sonic hedgehog (SHH)/GLI; (iv) WNT/beta-catenin; and (v) Bone Morphogenetic Protein (BMP)/SMAD. 70-80% of XP skin cancers exhibit one or several mutations in the P53, PTCH-1, SMO or CDKN2A genes, the type and frequency of mutated genes being different between squamous cell (SCCs) and basal cell carcinomas (BCCs). In XP cancers, the typically UVB-induced CC to TT tandem transitions represent approximately 60% of total mutations compared to 10-15% in skin tumours from DNA repair-proficient patients. Acquired activation of the pathways described herein can alter proliferation and differentiation of keratinocytes, allowing a damaged cell to replicate and give rise to mutated daughter cells, then eventually to the development of the carcinogenic process following clonal selection.
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PMID:UVB-induced mutations in human key gatekeeper genes governing signalling pathways and consequences for skin tumourigenesis. 1452 Dec 17

Understanding of molecular genetic mechanisms underlying prostate carcinogenesis would be greatly advanced by in vitro models of prostate tumors representing primary tumors. We have successfully established a neoplastic immortalized human prostate epithelial (HPE) clonal culture derived from a primary tumor of a prostate cancer patient (RC-58T) with hTERT, the catalytic subunit of telomerase. The early passage RC-58T cells derived from a radical prostatectomy specimen of a 52-year-old white male patient was transduced through infection with a retrovirus vector expressing the hTERT for the establishment of the RC-58T/hTERT cell line. One clonal line, soft-agar derived from the RC-58T/hTERT cell line, was isolated and further characterized phenotypically and genetically. These clonal (RC-58T/hTERT SA#4) cells are currently growing well at passage 70 and exhibit transformed morphology. The RC-58T/hTERT SA#4 line expressed a high level of telomerase activity and showed anchorage-independent growth in soft agar. The clonal line like the untransduced RC-58T cells (passage 3) expressed prostate specific antigen (PSA), androgen receptor (AR), prostate stem cell antigen (PSCA), and an androgen-regulated prostate specific gene NKX3.1, P16, and cytokeratin (CK) 8. Growth is slightly stimulated by dihydrotestosterone (DHT), and lyates are immunoreactive with AR antibody by Western blot analysis. More importantly, this clonal line produced adenocarcinomas when transplanted into SCID mice. A number of chromosome alterations were observed including the loss of chromosome Y, 1q, 2p, 3p, 4q, 8p, 11p, 14p, 17p and 18q. Our results demonstrate that this primary tumor-derived HPE cell line retained its neoplastic phenotypes and its prostate specific markers and should allow elucidating molecular and genetic alterations involved in prostate cancer. This is the first documented case of an AR and PSA expressing telomerase established human prostate cancer cell line with neoplastic phenotypes from a primary tumor of a prostate cancer patient.
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PMID:A telomerase-immortalized primary human prostate cancer clonal cell line with neoplastic phenotypes. 1537 56


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