Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C1140680 (ovarian cancer)
 28,141 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Genetic alterations of various cancers have been clarified by recent development of molecular biology. Multiple genetic alterations occur through the development of cancer. Both activation of proto-oncogenes and inactivation of tumor suppressor genes are important for the development of cancer. Alterations of oncogenes such as K-ras, c-erbB-2/HER-2/neu and c-myc, and those of tumor suppressor genes such as p53, RB and DCC have been reported in ovarian cancer. Allelic losses of the specific chromosomes, which suggest the existence of tumor suppressor genes on those chromosomes, also have been reported in ovarian cancer. Further studies on genetic alterations of ovarian cancer will clarify the mechanisms for the development of ovarian cancer and also will develop new methods for prevention, diagnosis and treatment in clinical.
 ...
PMID:[Genetic alterations in the genesis and development of ovarian cancer]. 135 31

Tumorigenesis is a multistep process involving mutations of dominantly acting proto-oncogenes and mutations and loss-of-function mutations of tumor suppressor genes. Some of these mutations may be inherited, but most of them are acquired. Models for the sequential steps of the genetic changes involved in tumor development have been proposed for certain cancers, such as colon cancer. In the case of ovarian cancer, relatively little is known about the genetic events associated with the initiation or subsequent progression and metastases of the tumor. Cytogenetic analysis has revealed a high incidence of both structural and numerical chromosome changes, and the extent of these changes seems to increase with tumor progression. Oncogene activations of the proto-oncogenes K-ras, c-myc and c-erbB-2 have been found more frequently in aggressive ovarian tumors and may be associated with poor survival. Tumor-specific allele loss involving putative tumor suppressor genes has been observed for loci at chromosomes 11p, 17p, and 17q,--loci commonly deleted in other cancers too. A relatively high incidence of allelic loss on chromosome 6q appears to be specific to ovarian carcinoma. Familial breast/ovarian cancer has been suggested to map to chromosome 8q. Recently we have found a germ-line mutation in the tumor suppressor gene p53 in a family with breast- and ovarian cancers, indicating that this is the predisposing gene in this family. Genetic changes important for the etiology of ovarian cancers seem to involve both somatic mutations of oncogenes and somatic or germ-line inactivation of tumor suppressor genes.
 ...
PMID:Oncogenesis in ovarian cancer. 150 89

It is difficult to identify early ovarian cancer at present. However, some tumor markers (CA125, CA19-9, CEA) and soon imaging system (MRI, CT, UT) and some oncogenes are available for diagnosis of ovarian cancer recently. Multivariate analysis of tumor markers has a possibility of stage I cancer. MRI is very useful to identify some cystic and hemorrhagic lesions. Amplifiers of N-myc and K-ras may be applied to diagnose ovarian cancer. In future, these new technologies may identify early ovarian cancer.
 ...
PMID:[New technology of diagnosis of ovarian cancer]. 284 69

The usefulness of prognostic factors in gynecological cancer was evaluated using the oncogenes, tumor suppressor genes and DNA viruses detected with the molecular biological technique. In uterine cervical cancer, HPV types 16 and 18 are considered to have a high oncogenic risk, and are commonly associated with high grade CIN and invasive cancer under persistent HPV infection. C-myc overexpression in advanced stage and p53 mutation in HPV negative case are associated with poor survival. In endometrial cancer, oncogene activation and expression are less frequent than in cervical and ovarian cancer. K-ras point mutation (codon 12) tumors are more aggressive and c-erbB-2 overexpression are associated with metastasis and poor survival. In ovarian cancer, there are numerous abnormalities of oncogenes and tumor suppressor genes. Especially, EGF-R and PDGF-R alpha expression are associated with decreased survival. p53 mutation also decreases survival and response to chemotherapy. Recently. MSH2 (Lynch II syndrome) and BRCA1 gene are known to relate with familial ovarian cancer.
 ...
PMID:[Evaluation of prognostic factors in gynecological cancer examined by molecular biological study]. 868 14

Alterations in specific oncogenes and tumor suppressor genes that serve as surrogate markers of malignant transformation have been identified in ovarian cancers. Overexpression of the HER-2/neu oncogene occurs in approximately 30% of breast and ovarian cancers. In most studies, HER-2/neu overexpression has correlated with poor survival. Although mutation of the K-ras oncogene has been found in some mucinous ovarian cancers, mutations in this gene appear to be more common in borderline ovarian tumors. Amplification of c-myc occurs in approximately 30% of ovarian cancers and is more frequently seen in serous cancers. Mutation of the p53 tumor suppressor gene, with resultant overexpression of mutant p53 protein, occurs in 50% of Stage III/IV and 15% of Stage I/II ovarian cancers. Most p53 mutations in ovarian cancers are transitions, which suggests that they arise spontaneously rather than due to exogenous carcinogens. In contrast to the acquired genetic alterations described above that are a feature of sporadic ovarian cancers, a small fraction of epithelial ovarian cancers arise due to inherited genetic defects. Recently, the BRCA1 tumor suppressor gene on chromosome 17q was identified and shown to be responsible for some cases of hereditary breast and ovarian cancer. Families in which mutations in this gene exist are usually characterized by early age of disease onset. Presently, it remains unclear what fraction of hereditary ovarian cancers are due to BRCA1 mutations.
 ...
PMID:Biomarkers in the ovary. 874

The many genetic changes associated with human carcinogenesis include the activation and/or inactivation of various genes. Polymerase-chain reaction and single-strand conformation polymorphism analysis [PCR-SSCP] was used to detect alterations at exon 1 of the K-ras gene in 20 lesions of human endometrium. Six cases of endometrial hyperplasia, 13 of endometrial carcinoma and one of endometrial metastasis of ovarian cancer were analyzed. Mutations at exon 1 of the K-ras gene were detected in two of 13 human endometrial carcinoma [15%]; both were histologically defined adenocarcinomas, stage Ib and stage IIa according to the FIGO. Alterations were also observed in the single case of endometrial metastasis of ovarian cancer. It is worthy of note that among the six women with hyperplasic endometrial lesions K-ras gene mutation were not reported. These data suggest that K-ras activation is rare in Polish women and when it does occur it is in cancerous, but not in precancerous, lesions of human endometrium.
 ...
PMID:Detection of K-ras mutations in cancerous lesions of human endometrium. 906 33

Epidemiologic studies have shown that the risk of cancer in the ovarian surface epithelium is decreased by factors that suppress ovulation, whereas uninterrupted ovulation has been associated with increased risk. This suggests that ovulation may play a critical role in ovarian carcinogenesis. More recently, molecular studies have demonstrated alterations in specific oncogenes and tumor suppressor genes in ovarian cancers. Overexpression of the HER-2/neu oncogene occurs in approximately 30% of ovarian cancers and correlates with poor survival. Although mutation of the K-ras oncogene has been found in some mucinous ovarian cancers, mutations in this gene appear to be more common in borderline ovarian tumors. Amplification of c-myc occurs in approximately 30% of ovarian cancers and is more frequently seen in serous cancers. Mutation of the p53 tumor suppressor gene, with resultant overexpression of mutant p53 protein, occurs in 50% of stage III/IV and 15% of stage I/II ovarian cancers. Most p53 mutations in ovarian cancers are transitions, which suggests that they arise spontaneously rather than due to exogenous carcinogens. In contrast to the acquired genetic alterations described above that are a feature of sporadic ovarian cancers, 5-10% of ovarian cancers probably arise due to inherited genetic defects. Recently, the BRCA1 tumor suppressor gene has heen identified and shown to be responsible for most cases of hereditary ovarian cancer. Further studies are needed to augment our understanding of the molecular pathogenesis of ovarian cancer.
 ...
PMID:Human ovarian cancer of the surface epithelium. 933 69

During the past decades, the expansion of molecular biology has had a pivotal role in understanding the basis of cancer development and progression. In addition, real advances have been made in the application of DNA recombinant technology to cancer therapy and patient management. In gynecologic oncologic fields, there are also many investigations to explore the basic pathogenesis of gynecologic cancer, such as cervical cancer, ovarian cancer, and endometrial cancer. It is now known that specific types of human papilloma virus (HPV) are the principal etiologic agents for both cervical cancer and its precursors. However, the various kinds of alterations in oncogenes and tumor suppressor genes may play additional roles in carcinogenesis of cervical cancer. Although ovarian carcinoma is the most frequent cause of death from gynecologic malignancies, the histogenesis and biological characteristics of these tumors are not well understood. During the last several years, many key observations have been made concerning the genetic alterations associated with ovarian cancer. Recent researches including some dominant oncogenes and tumor suppressor gene mutations common to these malignancies are providing bases to elucidate the mechanisms underlying this cancer. The most important basis of endometrial cancer is that K-ras and p53 mutations are also frequently observed.
 ...
PMID:Molecular genetics of gynecologic cancer. 936 94

Within past few years, the investigation of molecular genetic markers has had an increasing influence on clinical decisions about initial treatment and follow-up. This review presents data concerning the most studied and interesting molecular markers in ovarian cancer. p53 tumour suppressor gene, Bcl-2 oncogene, K-ras oncogene, c-erb2 proto oncogene, c-myc oncogene are examples of currently used molecular genetic markers. Some of these markers might be useful adjuncts for monitoring response to therapy, including early detection of tumour reactivation to allow curative therapy and rapid detection of treatment failure. The study of these markers may also lead to a better understanding of the biological characteristics of ovarian cancer. The information derived from studies of these markers also represents the most promising avenue towards new treatment strategies.
 ...
PMID:[Molecular markers in ovarian cancer]. 959 89

There is evidence that ovarian cancer may be derived from the progressive transformation of benign and/or borderline tumours. Mutations involving different oncogenes and tumour suppressor genes accumulate during the process of malignant transformation, and the alterations of genes involved in the pathogenesis of familial ovarian cancer are probably early events in ovarian tumorigenesis. BRCA-1 and BRCA-2 act as classical tumour suppressor genes in hereditary tumours, but their role in sporadic tumours remains controversial; however, a high frequency of allele losses in BRCA-1 (17q) and BRCA-2 (13q) loci has been observed in both familial and sporadic tumours. The possible role of mismatch repair genes and microsatellite instability is also controversial, but a role for them has been proposed in borderline tumours. Mutations in K-ras are specific for mucinous tumours and may be related to mucinous differentiation. Finally, a role in tumour progression has been proposed for both c-erb B-2 and p53, but their practical value in prognosis remains questionable.
 ...
PMID:Molecular pathology of ovarian carcinomas. 973 87


1 2 3 4 Next >>