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Patricia N Tonin

Publications and source records attributed to Patricia N Tonin.

17 recordsLinked to original sources
PubMed2007

Global analysis of chromosome X gene expression in primary cultures of normal ovarian surface epithelial cells and epithelial ovarian cancer cell lines.

The interpretation of loss of heterozygosity (LOH) in cancers is complicated as genes that map to LOH regions may be transcriptionally active (Xa) or inactive (Xi) due to X chromosome inactivation (XCI). We have analyzed the chromosome X transcriptome in four epithelial ovarian cancer (EOC) cell lines (TOV21G, TOV81D, TOV112D, and OV90) and 12 primary cultures of normal ovarian surface epithelial (NOSE) cells in relation to chromosome X integrity. Two-way comparative analysis using HuGeneFL Affymetrix GeneChips of TOV21G, TOV81D and OV90 relative to the NOSE samples was highly correlated (> 89%) in contrast to that of TOV112D (56-69%). TOV112D, followed by TOV21G, exhibited the largest number of up-regulated genes. XIST expression by RT-PCR was not detectable in TOV112D or TOV21G. Allele-specific transcription by cDNA sequence analysis of genes known to be subjected to XCI revealed maintenance of XCI in TOV81D and OV90, but not TOV21G. Biallelic expression could not be assessed in TOV112D due to reduction to hemizygosity of chromosome X. Chromosome X rearrangements were observed in FISH analysis of TOV112D and TOV21G, and both of these EOC cell lines were negative for Barr body analysis. The differentially expressed genes did not appear to map to any particular region of the X chromosome in any EOC cell line. The absence of XIST expression is consistent with Barr body loss in TOV112D and TOV21G. The combined evidence is consistent with two proposed mechanisms to account for absence of Xi in female cancers: Xi loss followed by Xa duplication (exemplified by TOV112D) and transcriptional reactivation of Xi (exemplified by TOV21G). Despite an alteration in XIST expression and differences in allelic content in the EOC cell lines, the chromosome X transcriptome was modified modestly when compared with that of NOSE samples.

Cell Line, Tumor↗
PubMed2006

SET complex in serous epithelial ovarian cancer.

With low cure rates but increasing diverse treatment options that provide variable remission times, ovarian cancer is increasingly being recognized as a chronic disease. This reality indicates the need for a better understanding of factors influencing disease progression. In a previous global analysis of gene expression, we identified genes differentially expressed when comparing serous epithelial ovarian tumors of low and high malignant potential (grade 0 vs grade 3). In this analysis, 4 out of 5 members of the SET complex, SET, APE1, NM23 and HMGB2, were highly expressed in invasive grade 3 tumors. To further investigate the expression of these genes and the fifth member of the SET complex (pp32), we performed immunohistochemistry, on a tissue array composed of 235 serous tumors of different grades and disease stages. A significant correlation between expression of all SET complex proteins and the tumor differentiation was observed (p < 0.05). When combining all tumors, overexpression of Nm23 (p = 0.04), Set (p = 0.004) and Ape1 (p = 0.004) was associated with the clinical stage of the disease. No marker by itself was associated with prognosis. The combination of a high level of Nm23 in the context of a low level of Set compared to all other combinations of these markers did confer a better prognosis (p = 0.03). When combined, high expression of Hmgb2 and low expression of Ape1 was also associated with patient prognosis (p = 0.05). These findings suggest that a strategy that sums the activities of different partners within a pathway may be more appropriate in designing nomograms for patient stratification.

Adult↗
PubMed2006

Tissue array analysis of expression microarray candidates identifies markers associated with tumor grade and outcome in serous epithelial ovarian cancer.

Molecular profiling is a powerful approach to identify potential clinical markers for diagnosis and prognosis as well as providing a better understanding of the biology of epithelial ovarian cancer. On the basis of the analysis of HuFL expression data, we have previously identified genes that distinguish low malignant potential and invasive serous epithelial ovarian tumors. In this study, we used immunohistochemistry to monitor a subset of differently expressed candidates (Ahr, Paep, Madh3, Ran, Met, Mek1, Ccne1, Ccd20, Cks1 and Cas). A tissue array composed of 244 serous tumors of different grades (0-3) and stages (I-IV) was used in this analysis. All markers assayed presented differential protein expression between serous tumors of low and high grade. Significant differences in Ccne1 and Ran expression were observed in a comparison of low malignant potential and grade 1 tumor samples (p<0.01). In addition, irrespective of the grade, Ccne1, Ran, Cdc20 and Cks1 showed significant differences of expression in association with the clinical stage of disease. While high level of Ccne1 have previously been associated with poor outcomes, here we found that high level of either Ran or Cdc20 appear to be more tightly associated with a poor prognosis (p<0.001, 0.03, respectively). The application of these biomarkers in both the initial diagnosis and prognostic attributes of patients with epithelial ovarian tumors should prove to be useful in patient management.

Basic Helix-Loop-Helix Proteins↗
PubMed2006

From gene profiling to diagnostic markers: IL-18 and FGF-2 complement CA125 as serum-based markers in epithelial ovarian cancer.

We used an oligonucleotide-based DNA microarray to identify potential markers in 39 primary cultures of ovarian cancer specimens compared with 11 primary cultures of normal ovarian epithelia. Differential gene expression of IL-18 and FGF-2 was validated on a subset of samples by quantitative PCR and by IHC, using an independent tissue array of 90 cores of 20 normal ovarian surface epithelia and 70 EOCs representing different grades and pathologies of ovarian disease. We further compared, by ELISA, these two markers with CA125 in sera from 25 cancer-free and 47 ovarian cancer patients. IL-18 and FGF-2 proteins were significantly elevated in tumor tissues (p<0.04) and sera (p<0.05) from patients with ovarian cancer. In combination, the three markers (IL-18, FGF-2, and CA125) showed similar sensitivity in scoring for ovarian cancer (35/45 patients) compared to that of CA125 alone (37/45) and significantly improved the specificity of detection (20/25 patients) compared to each marker individually (15/25 for CA125; 18/25 FGF-2; 16/25 for IL-18). In conclusion we show that a combination of the three serum markers (IL-18, FGF-2 and CA125) is associated with EOC, with higher specificity than CA125 alone. Prospective studies with a large cohort of susceptible ovarian cancer patients will be required to expand these findings.

Biomarkers, Tumor↗
PubMed2006

Haplotype analysis suggest common founders in carriers of the recurrent BRCA2 mutation, 3398delAAAAG, in French Canadian hereditary breast and/ovarian cancer families.

BACKGROUND: The 3398delAAAAG mutation in BRCA2 was recently found to recur in breast and/or ovarian cancer families from the French Canadian population of Quebec, a population that has genetic attributes consistent with a founder effect. To characterize the contribution of this mutation in this population, this study established the frequency of this mutation in breast and ovarian cancer cases unselected for family history of cancer, and determined if mutation carriers shared a common ancestry. METHODS: The frequency was estimated by assaying the mutation in series of French Canadian breast cancer cases diagnosed before age 41 (n = 60) or 80 (n = 127) years of age, and ovarian cancer cases (n = 80) unselected for family history of cancer by mutation analysis. Haplotype analysis was performed to determine if mutation carriers shared a common ancestry. Members from 11 families were analyzed using six polymorphic microsatellite markers (cen-D13S260-D13S1699-D13S1698-D13S1697-D13S1701-D13S171-tel) spanning approximately a 3.6 cM interval at the chromosomal region 13q13.1, which contains BRCA2. Allele frequencies were estimated by genotyping 47 unaffected female individuals derived from the same population. Haplotype reconstruction of unaffected individuals was performed using the program PHASE. RESULTS: The recurrent BRCA2 mutation occurred in 1 of 60 (1.7%) women diagnosed with breast cancer before 41 years of age and one of 80 (1.3%) women with ovarian cancer. No mutation carriers were identified in the series of breast cancer cases diagnosed before age 80. Mutation carriers harboured one of two haplotypes, 7-3-9-3 - [3/4]-7, that varied with marker D13S1701 and which occurred at a frequency of 0.001. The genetic analysis of D13S1695, a polymorphic marker located approximately 0.3 cM distal to D13S171, did not favour a genetic recombination event to account for the differences in D13S1701 alleles within the haplotype. Although mutation carriers harbour genotypes that are frequent in the French Canadian population, neither mutation-associated haplotype was plausible in reconstructed haplotypes of 47 individuals of French Canadian descent. CONCLUSION: These results suggest that mutation carriers share a related ancestry; further supporting the concept that recurrent BRCA1 and BRCA2 mutations in the French Canadian population could be attributed to common founders. This finding provides further support for targeted screening of recurrent mutations in this population before large-scale mutation analyses are performed.

Adult↗
PubMed2006

[The limited spectrum of pathogenic BRCA1 and BRCA2 mutations in the French Canadian breast and breast-ovarian cancer families, a founder population of Quebec, Canada].

The unique genetic demography of the French Canadian population of Quebec, Canada, has provided a means to study the contribution of BRCA1 and BRCA2, the breast-ovarian cancer susceptibility genes. Here we review BRCA1 and BRCA2 in the context of French Canadian cancer families, a well-characterized founder population known for its contributions to medical genetics. Pathogenic BRCA1 and BRCA2 mutations contribute to a significant proportion of hereditary breast and/or ovarian cancer families of French Canadian descent. BRCA1 and BRCA2 mutations have been reported in approximately 40 % of families with at least three cases of breast and/or ovarian cancer, where breast cancer diagnosis occurred before age 66 years, and where all cases occurred within first-, second- and/or third-degree relatives to index affected cases tested for mutations. The proportion of mutation-positive families was very similar to that reported in independent studies of families not selected for ethnicity. However, 84 % of mutation-positive families were accounted for by one of eight pathogenic mutations in BRCA1 (2953delGTA + C, 3875delGTCT, and 4446C --> T) and BRCA2 (2816insA, 3398delAAAAG, 6085G --> T, 6503delTT, and 8765delAG). Haplotype analyses has suggested that carriers of the most common recurring mutations share a related ancestry. This effect has been attributed to common founders in the French Canadian population of Quebec who emigrated from France in between 1608 and 1759. It is possible that novel highly penetrant cancer susceptibility genes account for a fraction of the 60 % of BRCA mutation-negative French Canadian cancer families. The continued genetic analysis and phenotypic characterization of French Canadian cancer families is warranted given the large family structure of these families are amenable for classical genome-wide linkage analysis for novel breast and ovarian cancer susceptibility genes.

Age Factors↗
PubMed2005

Discrimination between serous low malignant potential and invasive epithelial ovarian tumors using molecular profiling.

Tumors of low malignant potential (LMP) represent 20% of epithelial ovarian cancers (EOCs) and are associated with a better prognosis than the invasive tumors (TOV). Defining the relationship between LMPs and TOVs remains an important goal towards understanding the molecular pathways that contribute to prognosis, as well as providing molecular markers, for these EOCs. To this end, DNA microarray analyses were performed either in a primary culture or a tumor tissue model system and selected candidate genes showing a distinctive expression profile between LMPs and TOVs were identified using a class prediction approach based on three statistical methods of analysis. Both model systems appear relevant as candidate genes identified by either model allowed the proper reclassification of samples as either LMPs or TOVs. Selected candidate genes (CAS, CCNE1, LGALS8, ITGbeta3, ATP1B1, FLIP, KRT7 and KRT19) were validated by real-time quantitative PCR analysis and show differential expression between LMPs and TOVs. Immunohistochemistry analyses showed that the two tumor classes were distinguishable by their expression of CAS, TNFR1A, FLIP, CKS1 and CCNE1. These results define signature patterns for gene expression of LMPs and TOVs and identify gene candidates that warrant further study to deepen our understanding of the biology of EOC.

Diagnosis, Differential↗
PubMed2005

Loss of heterozygosity and transcriptome analyses of a 1.2 Mb candidate ovarian cancer tumor suppressor locus region at 17q25.1-q25.2.

Loss of heterozygosity (LOH) analysis was performed in epithelial ovarian cancers (EOC) to further characterize a previously identified candidate tumor suppressor gene (TSG) region encompassing D17S801 at chromosomal region 17q25.1. LOH of at least one informative marker was observed for 100 (71%) of 140 malignant EOC samples in an analysis of 6 polymorphic markers (cen-D17S1839-D17S785-D17S1817-D17S801-D17S751-D17S722-tel). The combined LOH analysis revealed a 453 kilobase (Kb) minimal region of deletion (MRD) bounded by D17S1817 and D17S751. Human and mouse genome assemblies were used to resolve marker inconsistencies in the D17S1839-D17S722 interval and identify candidates. The region contains 32 known and strongly predicted genes, 9 of which overlap the MRD. The reference genomic sequences share nearly identical gene structures and the organization of the region is highly collinear. Although, the region does not show any large internal duplications, a 1.5 Kb inverted duplicated sequence of 87% nucleotide identity was observed in a 13 Kb region surrounding D17S801. Transcriptome analysis by Affymetrix GeneChip and reverse transcription (RT)-polymerase chain reaction (PCR) methods of 3 well characterized EOC cell lines and primary cultures of normal ovarian surface epithelial (NOSE) cells was performed with 32 candidates spanning D17S1839-D17S722 interval. RT-PCR analysis of 8 known or strongly predicted genes residing in the MRD in 10 EOC samples, that exhibited LOH of the MRD, identified FLJ22341 as a strong candidate TSG. The proximal repeat sequence of D17S801 occurs 8 Kb upstream of the putative promoter region of FLJ22341. RT-PCR analysis of the EOC samples and cell lines identified DKFZP434P0316 that maps proximal to the MRD, as a candidate. While Affymetrix technology was useful for initially eliminating less promising candidates, subsequent RT-PCR analysis of well-characterized EOC samples was essential to prioritize TSG candidates for further study.

Chromosome Mapping↗
PubMed2005

Identification of novel variant, 1484delG in the 3'UTR of H3F3B, a member of the histone 3B replacement family, in ovarian tumors.

Previous studies have implicated the chromosomal region at 17q25 as harboring tumor suppressor genes based on the frequent loss of heterozygosity (LOH) observed in epithelial ovarian cancers (EOC). RT-PCR validation of Affymetrix GeneChip expression of H3F3B, a member of the 3B histone family that maps to 17q25.1, revealed a doublet band in cDNA from one of four EOC cell lines, OV90. In contrast to three other EOC cell lines (TOV81D, TOV112D and TOV21G) and primary cultures derived from normal ovarian surface epithelial cells (NOSE), sequence analysis of the cDNA revealed a deletion of G at position 1484 of the transcribed sequence which is located within the 3'UTR of H3F3B. OV90 was derived from ascites fluid of an undifferentiated adenocarcinoma of ovarian origin. The variant allele was identified in 1 of 65 (2%) healthy women with no prior history of cancer and in 5 participants with ovarian tumors comprising of 4 of 79 (5%) malignant EOC, none of 10 low malignancy potential tumors, and 1 of 8 (13%) benign tumors. All carriers of the variant alleles were heterozygous and tumor samples did not exhibit preferential LOH of the normal allele. The variant allele was identified in EOC samples of clear cell (1 of 20), mucinous (1 of 8), mixed cell (1 of 3) and undifferentiated (1 of 2) histopathological subtypes but none of 34 serous or 12 endometrioid subtype tumors. One of 3 mucinous benign tumors also harbored the variant allele. The functional significance of the variant is unknown, however its presence in rare subtypes of ovarian epithelial tumors warrants further investigation.

3' Untranslated Regions↗
PubMed2005

OGG1 Cys326 variant, allelic imbalance of chromosome band 3p25.3 and TP53 mutations in ovarian cancer.

A Ser326Cys amino acid variant encoded by OGG1 that removes the highly mutagenic 8-oxo-7,8-dihydroguanine adducts resulting from the oxidative damage produced by reactive oxygen species, has been suggested to reduce activity of the enzyme and result in an increase in G:C --> T:A transversions. Carriers homozygous for the Cys326 variant have been associated with increased risk in some cancers. In this study, we tested the association of this polymorphism with epithelial ovarian cancer (EOC) (n=91 cases) in comparison with women unaffected by the disease (n=57). Although the genotype encoding the homozygous Cys326 variant was found more often in cases (11%) than controls (9%), this was not statistically significant (p=0.297). As OGG1 at chromosome band 3p25.3 overlaps a region exhibiting allelic imbalance (AI) in EOC, we also examined the frequency of AI of the OGG1 locus and its association with somatic mutations in the TP53 tumor suppressor gene, which is frequently mutated in EOC. The frequency of AI and TP53 mutations in EOC was 32 and 37%, respectively. Although the proportion of EOC cases harboring the genotype homozygous for Cys326 was greater in TP53 mutation-positive cases (5 of 34, 15%) than mutation-negative cases (5 of 57, 9%), the distribution of genotypes was not significantly different (p=0.289). Four of the six heterozygous Ser326/Cys326 samples exhibiting AI, displayed loss of the Ser326 variant. About 16% of samples exhibited both AI of the OGG1 locus and a TP53 mutation. Proportionately more EOC samples harbored a mutation in the group of samples exhibiting AI (15 of 29, 52%) in comparison to the group of samples with no AI (19 of 62, 31%) (p=0.036). Although the OGG1 Cys326 variant appears to play a minor role in conferring increased risk of ovarian cancer, the observed AI of the OGG1 locus in association with TP53 somatic mutations warrants further investigation in this disease.

Allelic Imbalance↗
PubMed2004

Significant proportion of breast and/or ovarian cancer families of French Canadian descent harbor 1 of 5 BRCA1 and BRCA2 mutations.

In 1998, we reported that a significant proportion of breast and/or ovarian cancer families of French Canadian descent harbor specific germline mutations in BRCA1 or BRCA2 attributed to common founders. Here we report the frequency of previously described mutations (n = 7) and 13 mutations identified in French Canadian families since 1998, in a new group of families (n = 88). Four of the previously described mutations, 4446C>T, 2953delGTAinsC, 8765delAG and 6085C>T, account for 72% and 69% of mutation-positive families in previously (n = 81) and recently ascertained groups, respectively. Only 2 of 13 recently identified mutations were found in more than 1 family: 3875delGTCT (n = 2) and 3398delAAAAG (n = 4). The 2 groups (ascertained pre- and post-gene discovery) did not differ significantly when distribution of mutations based on cancer syndrome phenotype and age of diagnosis or number of breast cancer cases were compared. Five common mutations accounted for a significant proportion (84%) of all mutation-positive families. The age of diagnosis of female breast cancer in mutation-negative families was significantly higher than that of the mutation-positive families (p<0.0001). The total number of cases of cancer per family was significantly lower in mutation-negative than mutation-positive families (p<0.001). Our results define a new mutation panel for screening BRCA1/2 mutations and the phenotype of mutation-positive families harboring the common mutations in the French Canadian population.

Adult↗
PubMed2004

Gene expression microarray analysis and genome databases facilitate the characterization of a chromosome 22 derived homogeneously staining region.

Karyotype and fluorescence in situ hybridization (FISH) analyses previously identified a homogeneously staining region (HSR) derived from chromosome 22 in OV90, an epithelial ovarian cancer (EOC) cell line. Affymetrix expression microarrays in combination with the UniGene and Human Genome Browser databases were used to identify the candidate genes comprising the amplicon of the HSR, based on comparison of expression profiles of OV90, EOC cell lines lacking HSRs and primary cultures of normal ovarian surface epithelial (NOSE) cells. A group of probe sets displaying a minimum 3-fold overexpression with a high reliability score (P-call) in OV90 were identified which represented genes that mapped within a 1-2 Mb interval on chromosome 22. A large number of probe sets, some of which represent the same genes, displayed no evidence of overexpression and/or low reliability scores (A-call). An investigation of the probe set sequences with the Affymetrix and Sanger Institute Chromosome 22 Group databases revealed that some of the probe sets displaying discordant results for the same gene were complementary to intronic sequences and/or the antisense strand. Microarray results were validated by RT-PCR. Genomic analysis suggests that the HSR was derived from the amplification of a 1.1 Mb interval defined by the chromosomal map positions of ZNF74 and Hs.372662, at 22q11.21. The deduced amplicon is derived from a complex region of chromosome 22 that harbors low-copy repeats (LCRs). The amplicon contains 18 genes as likely targets for gene amplification. This study illustrates that large-scale expression microarray analysis in combination with genome databases is sufficient for deducing target genes associated with amplicons and stresses the importance of investigating probe set design before engaging in validation studies.

Cell Line, Tumor↗
PubMed2003

Patterns of expression of chromosome 17 genes in primary cultures of normal ovarian surface epithelia and epithelial ovarian cancer cell lines.

Oligonucleotide microarray analysis was applied to assess the expression profile of 332 probe sets representing 308 genes or expressed sequence tags (ESTs) that map to chromosome 17 in order to address epigenetic events that result in alterations in gene expression in epithelial ovarian cancer (EOC). Expression profiles were generated from 12 primary cultures derived from normal ovarian surface epithelium (NOSE) and four long-term cultures (TOV-81D, TOV-112D, TOV-21G and OV-90) derived from EOCs that have been previously characterized and shown to mimic features of the tumoral cells from which they were derived. The expression values of all 332 probe sets is highly correlated across the 12 NOSEs (89% correlation coefficients >0.90). In two-way comparisons, differential patterns of gene expression were observed for 157 probe sets for which the expression value of at least one EOC cell line fell outside the limits of the range of expression of the 12 NOSEs. When compared to NOSEs, four genes displayed similar differential patterns of gene expression across all four EOC cell lines, and 26 genes displayed similar differential patterns of gene expression across the three EOC cell lines (TOV-112D, TOV-21G and OV-90) representing tumoral cells derived from the most aggressive disease. A total of 17 genes displayed differential patterns of gene expression greater than threefold in at least one EOC cell line in comparison to NOSE, and three genes were differentially expressed greater than threefold across all aggressive cell lines. The analysis of a selected number of genes by RT-PCR revealed patterns of gene expression comparable to those observed by microarray analysis in the majority of samples tested. Comparison of expression profiles of differentially expressed genes identified by microarray analysis in two-way comparisons of the EOC cell lines and the NOSEs with published reports revealed 10 genes previously implicated in ovarian tumorigenesis and 18 in tumorigenesis of other types of cancer. The differential pattern of gene expression of genes that map to both the p and q arm of chromosome 17 is consistent with the hypothesis that a number of genes that map to this chromosome are implicated in the etiology of ovarian cancer.

Cells, Cultured↗
PubMed2003

The quest for a tumor suppressor gene phenotype.

Our current definitions of the tumor suppressor gene (TSG) have been guided by the identification of the prototypical gene, RB1, a TSG that is implicated in the development of both the inherited and sporadic forms of retinoblastoma. The hallmark feature of this TSG is loss of function in tumoral cells, which can be restored by reintroduction of a normally functioning protein with concomitant reversion of tumorigenicity. Key to this discovery was that loss of function is often achieved by deletion of a normal copy of the TSG and retention of a mutated allele, which was either inherited or acquired. Suppression of tumorigenicity and the loss-of-function concept of TSGs was also demonstrated in early studies where normal cellular growth was achieved when tumorigenic cells were fused with normal cells. Thus loss of genetic content and restoration of gene function has guided studies aimed at the discovery of novel TSGs. Here we review the successes of TSG discovery using three approaches that are based on the genetic analysis of inherited predisposition to cancer, tumors that display chromosome loss, and tumorigenic cells that display a suppression of tumorigenicity as a result of transfer of normal chromosomes. Based on a review of the literature we conclude that the discovery of TSGs has been highly successful in the genetic analysis of inherited predisposition to cancer with a dominant mode of inheritance. In contrast, the latter two approaches have yielded a paucity of TSGs that exhibit features similar to the prototypical RB1 in that they are rarely inactivated by somatic mutations in tumors displaying LOH, although decreased gene expression is observed. Nevertheless, some of these genes have been shown to suppress tumorigenicity when normal function is restored in tumorigenic cells consistent with the loss-of-function concept. These observations continue to challenge our current definition of TSG.

Animals↗
PubMed2002

Comparative analysis of loss of heterozygosity of specific chromosome 3, 13, 17, and X loci and TP53 mutations in human epithelial ovarian cancer.

We previously reported the identification of three minimal regions of deletion on the short arm of chromosome 3 (3p) in epithelial ovarian tumor specimens, suggesting that the inactivation of tumor-suppressor genes in these regions may be important in terms of ovarian tumorigenesis. Another previous study of ovarian cancer observed that allele loss of chromosome 179 was frequently found in ovarian tumors that also showed loss of heterozygosity (LOH) of chromosomes 3p, 13q, 17p, and Xp. In an independent study, we also reported a high frequency of LOH for selected chromosome 17 loci in high-grade and late-stage ovarian tumors. We have extended our LOH analysis of chromosome 3p to include 102 ovarian tumor specimens (29 and 73 samples were previously examined for LOH of chromosome 3p and 17 markers, respectively), using additional polymorphic markers, to assess the coordinate LOH of loci representing the three chromosome 3p minimal regions of deletions [von Hippel-Lindau syndrome (VHL), thyroid hormone receptor beta, and fragile histidine triad (FHIT)] and LOH of other important loci [tumor protein 53 (TP53), breast cancer 1 early onset (BRCA1), breast cancer 2 early onset, retinoblastoma 1, ornithine carbamoyltransferase, and androgen receptor] or somatic mutations in TP53. There was a significant association between LOH of any chromosome 3p marker and LOH of any chromosome 17 marker (P = 0.026). The frequency of LOH at the TP53 locus was higher in the group of samples that displayed LOH of a 3p marker (P = 0.019), as was the frequency of LOH at the BRCA1 locus (P = 0.014). LOH of chromosome 3p was noted in four specimens that did not display LOH of either the BRCA1 or the TP53 locus, indicating that LOH of these loci need not precede LOH of the chromosome 3p loci. We found a significant association between LOH of the VHL (3p25) locus and LOH of any chromosome 17 marker (P = 0.005), suggesting that there may be an important relationship, in the tumorigenesis of epithelial ovarian cancer, between a gene at 3p25 and a gene located on chromosome 17. Our results indicate that inactivation of p53 by somatic mutation is unlikely to be a prerequisite to chromosome 3p LOH, because we found no significant association between mutations in TP53 and LOH of the three chromosome 3p loci. The frequency of LOH at the FHIT locus at 3p14 increased significantly with advancing age at diagnosis (P = 0.018), as did the frequency of somatic TP53 mutations (P = 0.008).

Chromosomes, Human↗
PubMed2002

Expression profiles of 290 ESTs mapped to chromosome 3 in human epithelial ovarian cancer cell lines using DNA expression oligonucleotide microarrays.

We have investigated previously the utility of oligonucleotide expression microarray technology in an analysis of four spontaneously transformed epithelial ovarian cancer (EOC) cell lines, TOV-21G, TOV-81D, OV-90, and TOV-112D. Here, we examine the expression of 290 expressed sequence tags (ESTs) that map to human chromosome 3 in a primary culture derived from normal ovarian surface epithelium (NOSE), NOV-31, and the four spontaneously transformed EOC cell lines. One of these cell lines, OV-90, harbors a deletion of an entire chromosome 3p arm. Whereas the most aggressive cell lines (OV-90, TOV-112D, and TOV-21G) exhibited the highest levels of expression, assessed by the mean of expression values of all ESTs, OV-90 showed the lowest mean of expression of ESTs that map to the 3p arm in comparison with TOV-112D and TOV-21G. This difference in expression profile of 3p ESTs in OV-90 is also reflected in the ratio of expression of ESTs on 3p versus the 3q arm and in that the expression values of ESTs that map to 3p were more often lower than higher in OV-90 in two-way comparisons with NOV-31, TOV-21G, and TOV-112D. The loss of a 3p arm does not affect the pattern of differential expression in analyses based on the range of numeric expression values of each EST or fold differences in expression for each EST in comparison with NOV-31. However, 25 differentially expressed ESTs were identified on the basis of threefold differences in expression values between NOV-31 and any EOC cell line; and six of these ESTs were differentially expressed uniquely in OV-90. The investigation of these ESTs could facilitate the identification of novel chromosome 3 genes implicated in ovarian tumorigenesis.

Chromosome Mapping↗