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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Despite the relatively high prevalence of ovarian cancer (1% of American women will develop this disease in their lifetime) and recent developments in its molecular genetic understanding (several proto-oncogenes, such as AKT2 and cKRAS, and tumor suppressor genes, such as BRCA1 and BRCA2, have been implicated), little is known about the presence of ovarian tumors and cancer in women already diagnosed with other familial multiple tumor syndromes. In this review, we focus on the possible association of ovarian tumors with multiple endocrine neoplasias (MENs) and their related syndromes, such as Carney complex (CNC), Peutz-Jeghers syndrome (PJS), von Hippel-Lindau disease (VHLD), and Cowden's disease (CD). These conditions recently have been molecularly elucidated, and some of the genes responsible for them (including STK11/LKB1 and PTEN, the genes responsible for PJS and CD, respectively) have already been investigated in series of sporadic ovarian lesions, mostly carcinomas. A brief description of each disease is followed by a literature search for affected patients with ovarian tumors; we review our own experience with CNC patients and ovarian tumors. An association between PJS and CNC and ovarian neoplasms seems likely; carcinoids of the ovary may occur in patients with MEN 1. Only few patients with CD and VHLD have any ovarian pathology, but PTEN, the CD gene has been investigated in sporadic ovarian tumors. The aim of the present report is to alert clinicians who care for patients with MENs, CNC, PJS, VHLD, CD, and other syndromes for possible associations between various types of ovarian tumors and these conditions.
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PMID:Ovarian tumors associated with multiple endocrine neoplasias and related syndromes (Carney complex, Peutz-Jeghers syndrome, von Hippel-Lindau disease, Cowden's disease). 1214 81

Minimal deviation adenocarcinoma (MDA) is a well-differentiated variant of mucinous adenocarcinoma of the uterine cervix and is found relatively infrequently in the general population. However, MDA is strongly associated with Peutz-Jeghers syndrome (PJS), a rare hereditary autosomal disorder characterized by benign hamartomatous polyposis in the gastrointestinal tract and mucocutaneous pigmentation. A serine threonine kinase gene, STK11, has been identified as the tumor suppressor gene responsible for the PJS. In this study we investigated the possible direct role of STK11 in the development of MDA of the uterine cervix. Eleven rare cases of mucinous MDA, not known to be associated with PJS, were screened for the presence of mutations in the STK11 gene by single-strand conformation polymorphism analysis of PCR-amplified DNA fragments. Subsequently our findings were confirmed with cloning and sequencing. As a control, 24 cases of endocervical adenocarcinomas of other histologic subtypes, with no family history of PJS (19 mucinous adenocarcinomas, 4 endometrioid adenocarcinomas, and 1 clear cell adenocarcinoma), 15 cases of squamous cell carcinomas of the uterine cervix, 5 cases of endocervical glands with pyloric gland metaplasia, and 2 deeply situated nabothian cysts were investigated. Somatic mutations of the STK11 gene were confirmed in 6 (55%) of the 11 mucinous MDAs and 1 (5%) of the 19 mucinous adenocarcinomas, but not in the 5 nonmucinous adenocarcinomas, the 15 squamous cell carcinomas, nor the 5 endocervical glands with gastric metaplasia. MDAs with the STK11 mutation had a significantly poorer prognosis than MDAs without the STK11 mutation (p = 0.039). A germline mutation of STK11 was detected in one PJS patient with mucinous adenocarcinoma of the uterine cervix. These results suggest that mutations in the STK11 gene may play an important role in the etiology of MDA of the uterine cervix and may distinguish this rare tumor from other common types of adenocarcinoma of the uterine cervix.
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PMID:Mutations in the STK11 gene characterize minimal deviation adenocarcinoma of the uterine cervix. 1253 84

Despite high rates of loss of heterozygosity affecting various chromosomes, the number of tumor suppressor genes (TSGs) found to be consistently involved in primary liver cancer is low. In the past decade, characterization of homozygous deletions (HDs) in tumors has become instrumental to identify new TSGs or to reveal the influence of a particular TSG on the development of a specific tumor type. We performed a detailed HD profiling at 238 critical loci on a collection of 57 hepatobiliary tumor cell lines (hepatocellular, cholangiocellular, and bile duct carcinomas, hepatoblastomas, and immortalized hepatocytes). We identified HDs at 9 independent loci, the analysis of which was extended to 17 additional hepatobiliary tumor cell lines. In total, 34 homozygous losses involving 9 distinct genes were detected in the 74 cell lines analyzed. Besides expected deletions at the p16-INK4A/p14-ARF, FHIT, AXIN1, and p53 genes, we detected HDs at the PTEN, NF2, STK11, BAX, and LRPDIT genes that were formerly not known to be implicated in human liver tumorigenesis. In conclusion, our data suggest that these genes may represent novel liver tumor suppressive targets. Additional tumorigenic pathways should be carefully considered in hepatocarcinogenesis.
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PMID:Homozygous deletion scanning in hepatobiliary tumor cell lines reveals alternative pathways for liver carcinogenesis. 1266 63

High rates of loss of heterozygosity commonly affect multiple chromosomes in individual tumor types, yet the number of known tumor suppressor genes (TSGs) systematically mutated in the corresponding tumors is usually low. The search for homozygously deleted genome segments in tumor samples or cell lines has become a method of choice to identify major TSGs or to reveal their influence on the development of a given tumor type. Here, we report a detailed homozygous deletion (HD) profiling for 246 critical loci on a panel of 89 tumor cell lines containing significant subsets of lung, ovarian and head and neck squamous cell carcinomas. We found a total of 53 HDs affecting 17 loci. The major target for HDs was p16-INK4A/p14-ARF (23/89, 26% of cases). Among the remaining alterations, HDs affecting TP73 or telomeric markers have never been previously described, whereas other HDs represent the first examples associating lesions of certain TSGs with a given tumor type (NF2 in lung and ovarian cells, STK11 in HELA cells). Overall, tumor cell lines established from ovarian or lung carcinomas displayed a surprising diversity of loci targeted by HDs with 7 and 6 loci involved, respectively. Our data suggest that, beside allelotyping or transcriptome/proteome studies, extensive HD profiling represents a promising approach for the detection of hitherto not implicated signalling pathways of tumorigenesis.
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PMID:Homozygous deletions scanning in tumor cell lines detects previously unsuspected loci. 1280 Jan 97

The inherited hamartoma polyposis syndromes encompass several distinct clinical syndromes with different genetic bases, Cowden syndrome (CS), Bannayan-Riley-Ruvalcaba syndrome (BRRS), juvenile polyposis syndrome (JPS), and Peutz-Jeghers syndrome (PJS). Germline mutations in PTEN, encoding a tumor suppressor phosphatase on 10q23.3, is associated with 80% of CS and 60% of BRRS. JPS is caused by mutations in MADH4 and BMPR1A, encoding two members of the TGFB superfamily. Germline mutations in LKB1 (STK11) are associated with a subset of PJS. The number, distribution, and histologic type of polyps differ amongst these syndromes as do component cancer risks. While rare, usually asymptomatic, hamartomatous polyps are felt to be component to CS. Hamartomatous polyposis is usually prominent and symptomatic in BRRS. Polyposis, which can be quite symptomatic, is a cardinal component feature of PJS and JPS. Interestingly, glycogenic acanthosis of the esophagus is highly predictive of CS and the presence of PTEN mutation. PTEN mutation positive CS have been shown to be at increased risk of breast, thyroid, and endometrial cancer. PTEN mutation positive BRRS are at increased risk of at least breast cancer, possibly that of the thyroid as well. In contrast, JPS and PJS have increased risk of gastrointestinal cancers in particular. Thus, molecular-based diagnoses to differentiate each of these syndromes are important for medical management.
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PMID:Constipation, polyps, or cancer? Let PTEN predict your future. 1451 69

Genetic linkage studies have led to the identification of highly penetrant genes as the possible cause of inherited cancer risk in many cancer-prone families. Most women with a family history of breast/ovarian cancer have tumors characterized by alterations in particular genes, mainly BRCA1 and BRCA2, but also CHK2, ATM, STK11 and others. This paper examines the BRCA1 and BRCA2 genes, focusing on the Italian pattern of mutations. The function of these two genes, classified as tumor suppressors, is linked with key metabolic mechanisms such as DNA damage repair, regulation of gene expression and cell cycle control. The pathological BRCA allelic variants may cause alteration of protein function, transcriptional activity and DNA repair; accumulation of the defects leads to widespread chromosome instability that may be directly responsible for cancer formation. In fact, mutations in BRCA1 and BRCA2, conferring a highly increased susceptibility to breast and ovarian cancer, do not lead to cancer by themselves. The current consensus is that these are 'caretaker' genes, which, when inactivated, allow other genetic defects to accumulate. The nature of these other molecular events may define the pathway through which BRCA1 and BRCA2 act. The BRCA mutation spectrum is complex, and the significance of most nucleotide alterations is difficult to understand. Moreover, the mutation pattern seems to be related to ethnicity. The Italian Consortium of Hereditary Breast and Ovarian Cancer has reviewed 1758 families; 23% have been found to be carriers of pathogenetic mutations in BRCA1 or BRCA2. Founder mutations have been described in geographically restricted areas of Italy; a regional founder effect has been demonstrated in Italy for the mutations BRCA1 5083del19 and BRCA2 8765delAG, and a probable new founder mutation has been characterized in Tuscany. The presence of founder mutations has practical implications for genetic testing.
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PMID:Genetic alterations in hereditary breast cancer. 1528 Jan 80

In breast cancer, a high frequency of genomic deletion is found in chromosomal region 19p13. Of particular interest is that the LKB1 gene (also known as STK11) has been mapped to this region. LKB1 is responsible for Peutz-Jeghers syndrome (PJS), a genetic disease characterized by mucocutaneous pigmentation and gastrointestinal hematoma with an increased risk of developing cancer, including breast cancer. To further clarify the role of chromosomal region 19p13.2-13.3 in the pathogenesis of breast cancer and to identify more precisely candidate tumor-suppressor genes (TSGs) for positional cloning studies, we performed detailed high-resolution allelotyping analysis to detect allelic loss or loss of heterozygosity (LOH) in this region on microdissected samples from 140 primary breast tumors using 24 microsatellite markers. The highest frequencies of LOH were seen with D19S883 (30%) and D19S216 (29%), both at 19p13.3, D19S922 (28%), at 19p13.3-19p13.2, and D19S865 (39%), at 19p13.2; in addition, identification was made of at least four common deletion regions, including the LKB1 locus, that are centered on these four markers. In all the cases, we found discontinuous allele loss at several 19p13.2-13.3 sites in the same tumor (with the markers with the highest frequency of LOH adjacent to markers retaining heterozygosity), suggesting the presence of multiple TSGs. Interestingly, in tumors, the extent of allelic loss at these markers (measured as the fractional allele loss) increased significantly as the tumors progressed to poorer grades (P < 0.05). We conclude that 19p13.2-13.3 allele loss is a common event in the pathogenesis of breast carcinoma that often involves discontinuous LOH of multiple, localized TSGs (including LKB1), the concurrent inactivation of which may contribute to breast cancer progression.
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PMID:High-resolution 19p13.2-13.3 allelotyping of breast carcinomas demonstrates frequent loss of heterozygosity. 1533 48

Germ line mutations in the STK11/LKB1 tumor-suppressor gene (chromosome 19p13.3) are responsible for the Peutz-Jeghers syndrome (PJS). PJS patients frequently develop neoplasms of various organs. Ovarian sex cord-stromal tumor (SCST) with annular tubules, which shows a characteristic morphology intermediate between granulosa cell and Sertoli cell tumors, is distinctively associated with PJS. Although somatic mutations of STK11 are reportedly rare in sporadic forms of common cancers linked to PJS, there are no available studies assessing STK11 alterations in larger series of sporadic ovarian tumors with granulosa, Sertoli or combined differentiation. We examined 29 sporadic SCSTs for loss of heterozygosity (LOH) at 19p13.3, mutation, and promoter methylation of STK11. LOH at 19p13.3 was detected in 12 of 29 (41%) SCSTs, with the highest frequency at chromosome marker D19S894, which localizes approximately 3 mb centromeric to STK11, and it was more frequent in granulosa/Sertoli-stromal cell tumors (10 of 19; 52%) than in thecoma-fibroma tumors (2 of 10; 20%). The 2 fibrothecomas harboring LOH contained sex cord elements. None of the LOH-positive SCSTs demonstrated mutations or promoter methylation of STK11. Our results indicate that LOH at 19p13.3 in sporadic SCSTs targets a gene different from STK11, and may play a role in the pathogenesis of sporadic SCSTs, especially in tumors containing sex cord derivatives.
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PMID:The STK11/LKB1 Peutz-Jegher gene is not involved in the pathogenesis of sporadic sex cord-stromal tumors, although loss of heterozygosity at 19p13.3 indicates other gene alteration in these tumors. 1534 12

Peutz-Jeghers syndrome (PJS) is an autosomal-dominant polyposis disorder with an increased risk of multiple cancer. The LKB1/STK11 gene, which acts as a tumor suppressor, is responsible for PJS and plays a role in suppressing breast cancer. The low expression of LKB1/STK11 in sporadic breast cancer is significantly associated with shorter survival. Here we describe a PJS patient with aggressive breast cancer that carried not only a germline mutation of LKB1/STK11 but also loss of the normal allele. The combination of these mutations may be associated with the poor prognosis of this patient. To our knowledge, we are the first to show that a germline mutation causing PJS is combined with the loss of the homologous normal allele of LKB1/STK11 in breast cancer.
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PMID:Germline mutation of the LKB1/STK11 gene with loss of the normal allele in an aggressive breast cancer of Peutz-Jeghers syndrome. 1571 5

Germline mutations of the LKB1 (STK11) tumor suppressor gene lead to Peutz-Jeghers syndrome (PJS) and predisposition to cancer. LKB1 encodes a serine/threonine kinase generally inactivated in PJS patients. We identified the dual phosphatase and tumor suppressor protein PTEN as an LKB1-interacting protein. Several LKB1 point mutations associated with PJS disrupt the interaction with PTEN suggesting that the loss of this interaction might contribute to PJS. Although PTEN and LKB1 are predominantly cytoplasmic and nuclear, respectively, their interaction leads to a cytoplasmic relocalization of LKB1. In addition, we show that PTEN is a substrate of the kinase LKB1 in vitro. As PTEN is a dual phosphatase mutated in autosomal inherited disorders with phenotypes similar to those of PJS (Bannayan-Riley-Ruvalcaba syndrome and Cowden disease), our study suggests a functional link between the proteins involved in different hamartomatous polyposis syndromes and emphasizes the central role played by LKB1 as a tumor suppressor in the small intestine.
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PMID:LKB1 interacts with and phosphorylates PTEN: a functional link between two proteins involved in cancer predisposing syndromes. 1598 3


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