Detailed deletion mapping on chromosome 1p32-p36 in human colorectal cancer: identification of three distinct regions of common allelic loss

Recent studies have suggested the existence of one or several tumor-suppressor genes on chromosome arm 1p in colorectal tumors. To determine the localization of the putative tumor suppressor genes, we performed LOH analysis in 1p in colorectal tumors. A total of 48 paired normal and tumor DNAs of 46 colorectal tumor patients and 21 microsatellite markers on 1p32.1-p36.3 were used for PCR-LOH analysis. Three commonly deleted regions were found: i) 1p36.3 (10-cm); ii) 1p35.1-p36.3 (2-cm); and iii) 1p34.2-p35 (1-cm). These regions overlapped with those reported in several types of tumor. No significant associations were found between LOH and clinicopathologic features. The regions identified in the present study could harbor tumor suppressor genes that would also be associated with several types of human cancer.     

Allelic deletion on chromosome 17p13.3 in early ovarian cancer

Multiple chromosome 17 loci may be involved in ovarian carcinogenesis. Fifty-seven sporadic ovarian epithelial tumors were examined for loss of heterozygosity at 15 loci on chromosomes 17p. Eighty % (39 of 49) of informative tumors had allelic loss in 17p13.3 at D17S30, D17S28, or both loci within this region, including 3 of 7 tumors of low malignant potential and 4 of 5 nonmetastatic carcinomas. The smallest region of overlapping deletions extends from D17S28 to D17S30, a distance of 15 kb. Furthermore, several tumors have breakpoints within the region detected by the D17S30 probe. Chromosome 17p13.3 genes with potential tumor suppressor function include HIC-1, DPH2L (N. J. Phillips et al. Isolation of a human diphthamide biosynthesis gene on chromosome 17p13.3, submitted for publication)/OVCA1, PEDF, and CRK. The HIC-1 coding sequence lies i kb centromeric to the D17S28-S17S30 region of deletion (M. Makos Wales et al., Nat. Med., 1:570-577, 1995) but remains a candidate because 5'-regulatory elements may lie within the critical region. Portions of the DPH2L/OVCA1 coding sequence lie within the D17S28-D17S30 interval. Somatic cell hybrid analysis places PEDF in an interval including D17S28, D17S30, and D17S54, whereas CRK is excluded from this interval. Chromosome 17p13.3 loss precedes TP53 and BRCA1 region deletions because the latter changes are see only in high-stage carcinomas. Microsatellite instability plays only a minor role in sporadic ovarian carcinogenesis because only 1 of 57 tumors showed this finding.     

Inverted duplication/deletion of chromosome 8p: mild clinical phenotype

PURPOSE: To report an adverse side effect associated with topical latanoprost usage. METHOD: Case report. A 76-year-old woman with primary open-angle glaucoma developed an iris cyst 5 weeks after beginning treatment with latanoprost. Clinical examinations and slit-lamp photographs were performed. RESULTS: Latanoprost was discontinued. Periodic examinations disclosed that the iris cyst gradually diminished and finally disappeared within 3 weeks. CONCLUSION: The formation of an iris cyst is a possible complication of topical latanoprost therapy.     

Small structural changes of chromosome 8. Two cases with evidence for deletion

The degeneration of the substantia nigra that characterises Parkinson's disease may cause an alteration in sensitivity of striatal dopamine receptors. The development of denervation supersensitivity has been held to be responsible for some of the effects of chronic levodopa therapy. The rotating rodent is an animal model commonly used to study the phenomenon of striatal dopamine receptor supersensitivity, and to investigate drugs which may prove to be beneficial in the treatment of Parkinson's disease. We have investigated as to whether long-term oral administration of levodopa to mice with unilateral destruction of striatal dopaminergic nerve terminals influences dopaminergic receptor denervation supersensitivity as judged by the circling response following systemically administered levodopa. It does not do so and the relevance of these findings to the treatment of Parkinson's disease is discussed.     

Detailed physical and deletion mapping of 8p with isolation of YAC clones from tumour suppressor loci involved in colorectal cancer

Loss of heterozygosity (LOH) of markers at chromosome 8p is frequently noted in many different tumour types, including colorectal cancer. Numerous investigations indicate the presence of more than tumour suppressor gene (TSG) located on 8p. In this study, we describe a detailed LOH map in colorectal cancer and relate this to physical mapping data from reduced radiation 8p hybrids, yeast artificial chromosome (YAC) co-localisation of markers and fluorescence in situ hybridisation data. These data indicate the presence of two regions harbouring putative TSG's between the polymorphic markers for the LPL gene-D8S298 (approximately 4 Mb) and the markers D8S136-D8S137 (approximately 8 Mb). Yeast Artificial Chromosomes (YAC) have been isolated from these regions of interest to aid the localisation of the putative TSG's.     

Localization of chromosome 8p regions involved in early tumorigenesis of oral and laryngeal squamous carcinoma

We analysed 30 primary invasive oral and laryngeal squamous carcinomas (SC), with concurrent dysplastic lesions, for genetic alterations at 15 microsatellite loci on the short arm of chromosome 8. Overall, loss of heterozygosity (LOH) was observed, in at least one informative locus, in 27% of the dysplastic lesions and in 67% of the invasive carcinomas. The highest frequency of allele losses in dysplasia (20% and 17%), and invasive carcinoma (40% and 48%) were detected in the same D8S298 and LPL-tet loci located on chromosomes 8p21 and 8p22 respectively. The minimal region with LOH was limited to 4.6 megaBases (mBs) at 8p22 and 7.1 mBs at 8p21. In addition, allelic losses in both dysplastic and corresponding invasive specimens were noted at the same loci in some tumors suggesting their emergence from a common preneoplastic clone. Allele losses correlated significantly with male gender, oral and laryngeal sites and high proliferative index. The data suggest that inactivation of tumor suppressor gene(s), within these loci, may constitute an early event in the evolution of oral and laryngeal SC.     

Microsatellite analysis reveals deletion of a large region at chromosome 8p in conventional renal cell carcinoma

We describe the case of a 33-year-old Caucasian male with follicular mucinosis successfully treated with isotretinoin. Follicular mucinosis is a primary idiopathic disease or a secondary, lymphoma-associated dermatosis. An effective standard therapy for this disease is unknown. In our case, isotretinoin led to a dramatic improvement of the skin lesions in about two weeks. To the best of our knowledge, the benefits of isotretinoin in the treatment of follicular mucinosis have never been reported previously. The efficacy of this drug could be mediated by a regulatory effect on the infiltrating cells and/or by a modulation of the target organ (skin) response to the infiltrating cells.     

A region-specific microdissection library for human chromosome 2p23-->p21 and the analysis of an interstitial deletion of 2p21

A region-specific library of human chromosome 2p23-->p21 was constructed using microdissection and microcloning techniques. Analysis of 94 single-copy microclones from the library showed that 64% were derived from the dissected region. Ten microclones were further mapped to the 2p21 region using a patient with an interstitial deletion of 2p21 and displaying holoprosencephaly, an abnormal embryonic development in midbrain and midface.     

K-ras mutation and loss of heterozygosity of chromosome 17p and survival in colorectal cancer

For the organism, adaptation corresponds to a physiological response to a problem raised by a modification in the internal medium and/or the environment while preserving homeostasis. Adaptations to muscle exercise can involve changes in metabolic, respiratory, or nutritional, or nutritional functions or any other modifications whose endpoint is the production more ATP for further muscle exercise. Adaptations occur at all the levels of the oxygen transport chain. We will thus focus successively on the notions of VO2max, ventilatory adaptations, thresholds, respiratory exchange, cardiac and vascular adaptations and peripheral adaptations.     

Genetic alterations in the region of the p53 gene on human chromosome 17 in colorectal cancer]

Most colorectal tumors are characterized, among other genetic alterations, by allele loss of the genes located on the short arm of chromosome 17 (17p13.1), including the p53 suppressor gene. In ovarian and mammary-gland tumors, deletions of another candidate tumor-suppressor gene, located in the 17p13.3 chromosome region, were observed. We analyzed allele losses in the loci of the short arm of chromosome 17 (YNZ22, MCT35.1, and the p53 gene) in colorectal-cancer patients from the former Soviet Union. Tumors with cytogenetic alterations in 17p and/or with a detected loss of heterozygosity at the YNZ22 (D17S30) locus were examined for allele losses in the p53 gene using two polymorphic sites. Different methods revealed alterations on 17p in 24 (48%) out of 50 patients with colorectal carcinomas. In all tumors with an allele loss of the YNZ22 marker (15 out of 44 informative cases), which was detected by means of PCR, allele loss of the p53 gene was found (12 out of 15 informative cases). In 5 out of 13 tumors with cytogenetic alterations in 17p, allele loss of the p53 gene was found, with the YNZ22 marker being unaffected. In one of these tumors, the i(17q) marker was found, and in the remaining four tumors, 17p translocations were detected. In 4 out of 5 tumors with translocations affecting 17p, the t(17;20)(q21;p12) translocation was detected. The informativeness of the screening for 17p translocations, using PCR for the YNZ22 locus, and the reasons for discrepancy between the data of PCR and cytogenetic analyses are discussed.     

p53 and colorectal cancer

Mutations of the p53 gene have been found in 380 of the 768 tumors (49.5%) included in the eight largest published series of colorectal cancer. Most point mutations of p53 change the conformation of the gene, and by stabilizing it make it detectable by immunohistochemistry. However, studies using both tests for p53 mutations and immunohistochemical methods found that the results of these two approaches were concordant in only 68% of cases. Conflicting data have been reported regarding the prognostic significance of positive p53 staining. Presence of a mutation is generally believed to indicate a poor prognosis.     

Identification of a homozygous deletion at 8p12-21 in a human prostate cancer xenograft

Endothelial-monocyte activating polypeptide II (EMAP II) and allograft-inflammatory factor-1 (AIF-1) are two proteins produced by activated monocytes and microglial cells. We now report expression of these factors during experimental therapy of rat neuroautoimmune diseases. Comparative analysis of two therapeutic strategies, treatment with high doses of recombinant autoantigens or with dexamethasone, revealed unexpected differences. High doses of autoantigen were most effective in experimental autoimmune encephalomyelitis and neuritis (EAE and EAN), but less effective in experimental autoimmune uveitis (EAU). Low and high doses of dexamethasone treatment greatly reduced the severity of EAE, EAN and EAU at day 11, but a relapse was observed between days 21 and 26. Only rather limited expression of EMAP II and AIF-1 is seen in the normal central nervous system (CNS). This constitutive expression is not abolished by dexamethasone treatment. In inflammatory autoimmune lesions of the rat CNS, prominent AIF-1 and EMAP II staining was seen with macrophages and monocytes. In particular, parenchymal microglial cells were now activated to express AIF-1 and EMAP II. In accordance with prevention of neurological signs, histological observations revealed that accumulation of activated monocytes expressing EMAP II and AIF-1 in the CNS or peripheral nervous system and the massive expression of these factors by parenchymal microglial cells is inhibited by high doses of autoantigen. Dexamethasone prevented or abolished local expression of EMAP II and AIF-1 at days 10-16. However, an acute and severe relapse occurred in encephalomyelitis between days 20-26. In these cases, a smoldering expression of EMAP II and AIF-1 persisting long after cessation of neurological signs was observed. Thus, expression of EMAP II and AIF-1 by infiltrating activated macrophages is a marker of disease activity and expression of these factors could be used to demonstrate 'silent' lesions in the CNS and prolonged microglial cell activation. Apparently, AIF-1 and EMAP II immunoreactivity are tools to stage activation of monocytes and microglial cells in inflammatory lesions.     

Distinct regions of frequent loss of heterozygosity of chromosome 5p and 5q in human esophageal cancer

Twenty strains of Streptococcus bovis grew more slowly on lactose (1.21 +/- 0.12 h-1) then than on glucose (1.67 +/- 0.12 h-1), and repeated transfers or prolonged growth in continuous culture (more than 200 generations each) did not enhance the growth rate on lactose. Lactose transport activity was poorly correlated with growth rate, and slow growth could not be explained by the ATP production rate (catabolic rate). Batch cultures growing on lactose always had less intracellular fructose 1,6-bisphosphate (Frul,6P2) than cells growing on glucose (6.6 mM compared to 16.7 mM), and this difference could be explained by the pathway of carbon metabolism. Glucose and the glucose moiety of lactose were metabolized by the Embden-Meyerhoff-Parnas (EMP) pathway, but the galactose moiety of lactose was catabolized by the tagatose pathway, a scheme that by-passed Frul,6P2. A mutant capable of co-metabolizing lactose and glucose grew more rapidly when glucose was added, even though the total rate of hexose fermentation did not change. Wild-type S. bovis grew rapidly with galactose and melibiose, but these galactose-containing sugars were activated by galactokinase and catabolized via EMP. On the basis of these results, rapid glycolytic flux through the EMP pathway is needed for the rapid growth (more than 1.2 h-1) of S. bovis.     

p53 and prognosis in colorectal cancer

Treatment of rat liver arginase with N-bromosuccinimide results in modification of six tryptophan residues per enzyme molecule and is accompanied by loss of catalytic activity (E. Ber and G. Muzynska (1979) Acta Biochim. Pol. 26, 103-114). In order to probe the chemistry of N-bromosuccinimide inactivation and the role of tryptophan residues in catalysis, the two tryptophan residues of rat liver arginase, Trp122 and Trp164, have been separately mutated to phenylalanine using site-directed mutagenesis of the protein expressed in Escherichia coli. Both single Trp -> Phe mutant enzymes have kinetic parameters nearly identical to those for the wild-type enzyme. Treatment of native, wild-type, and each of the Trp -> Phe mutant enzymes with N-bromosuccinimide results in loss of absorbance at 280 nm and is accompanied by a loss of catalytic activity. However, treatment of the wild-type enzyme with N-bromosuccinimide in the presence of the arginase inhibitors NG-hydroxy-L-arginine or the combination of L-ornithine and borate protects against inactivation, even though tryptophan residues are modified. Treatment of the H101N and H126N mutant arginases with N-bromosuccinimide also results in loss of catalytic activity and modification of tryptophan residues. In contrast, the H141N mutant arginase is not inactivated by N-bromosuccinimide, indicating that His141 is the critical target for the N-bromosuccinimide inactivation of the enzyme.     

A de novo interstitial deletion of chromosome 15 band q25 as revealed by FISH-technique

We report a new chromosomal finding in a 20 month-old girl. The minor clinical features included: moderate mental retardation, microcephaly, mild hypotonia and hypertelorism. Initially, what appeared to be a terminal deletion of the long arm of one chromosome 15 [15q26-->qter] was determined to be an interstitial deletion involving band 15q25 as revealed by FISH-technique, showing the presence of intact telomeric hybridization signals. The cytogenetic diagnosis was thus modified to 46,XX, del (15) (pter-->q24::q26--> qter). Nevertheless, the function of the enzyme telomerase should not be ignored, as healing could occur following such terminal deletions. Consequently, it will remain a difficult task to distinguish terminal deletions from those that are interstitial.     

Mutational analysis of the p73 gene localized at chromosome 1p36.3 in colorectal carcinomas

A case of chordoid meningioma occurring in a 15-year-old girl is presented. The patient manifested seizures as the initial symptom and subsequently exhibited subclinical microcytic hypochromic anemia. The tumor, located in the falcotentorial region and associated with diffuse edema, was totally resected. On histological examination of the surgical specimen, the clustering pattern of partly vacuolated cells in the mucoid stroma mimicked chordoma; however, positive staining of individual cells for vimentin and epithelial membrane antigen led to a diagnosis of meningioma. Interestingly, the tumor cells were surrounded by a periodic acid-Schiff- and type IV collagen-positive substance. Electron microscopy demonstrated a strikingly dense and thick basal lamina. The patient's microcytic hypochromic anemia disappeared after the tumor was removed. Both the clinical and pathological features of this case resemble those of chordoid meningioma, a rare meningioma variant.