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P J Goodfellow

Publications and source records attributed to P J Goodfellow.

At least 37 records · Page 2Linked to original sources
PubMed1998

Four new mutations in the DNA mismatch repair gene MLH1 in colorectal cancers with microsatellite instability. Mutations in brief no. 157. Online.

Hereditary nonpolyposis colorectal cancer (HNPCC) is frequently associated with inherited mutation in one of four DNA mismatch repair genes. Somatic mutations in the same genes are also found in a subset of sporadic colorectal cancers. A defect in DNA mismatch repair results in a RER (replication error) tumor phenotype. We screened 110 archival and 11 prospectively acquired colorectal cancers for the RER phenotype. A total of 22 cancers were RER-positive. RER-positive tumors were investigated for mutations in the DNA mismatch repair gene MLH1 using single-strand-conformation-polymorphism (SSCP) analysis. We identified four previously undescribed mutations in four different samples. Three mutations were exonic: a point mutation at codon 69 (AGG-->AAG(arg-->lys]); a single base pair deletion at codon 42/43 (GCAAAATCC-->GCAAATCC) leading to a new stop codon downstream; and a point mutation at codon 757 (TAA-->TAT [termination-->tyr] which extend the MLH1 peptide by 36 ammino acids. The fourth mutation was a 1 base pair insertion six base pairs 5' to the start of exon 14 (tttgtttt-->tttggtttt). The mutations were not seen in the patients' constitutional DNA. The somatic MLHI mutations identified appear to be causally associated with the RER phenotype.

Adaptor Proteins, Signal Transducing↗
PubMed1998

PTEN mutations in endometrial cancers with 10q LOH: additional evidence for the involvement of multiple tumor suppressors.

OBJECTIVE: The aim of this study was to assess the involvement of PTEN and other putative 10q tumor suppressors in endometrioid-type adenocarcinomas characterized by loss of 10q sequences. METHODS: PCR-based single-stranded conformational variant analysis and sequencing of individual PTEN exons in 34 tumor specimens and their corresponding normal DNA were used. RESULTS: Thirteen of the 34 tumors (38%) revealed a PTEN mutation: 2 frameshift, 3 nonsense, 3 missense, 3 splice site alterations, and 2 homozygous deletions. CONCLUSION: The observation that greater than 60% of endometrial cancers with 10q LOH lack PTEN mutations, in addition to previously reported LOH data, provides evidence for the existence of other tumor suppressors on 10q. Consideration of PTEN mutation status may prove important in deletion mapping studies to locate additional tumor suppressors on the long arm of chromosome 10.

Endometrial Neoplasms↗
PubMed1998

Confirmation that chromosome 18q allelic loss in colon cancer is a prognostic indicator.

PURPOSE: Recent studies suggest that allelic loss of sequences from the long arm of chromosome 18 may be a useful prognostic indicator in colorectal cancer. The aim of the present study was to confirm whether 18q loss of heterozygosity (LOH) is of prognostic value in patients with colon cancer. METHODS: Genomic DNA was prepared from archival tumor and corresponding normal tissue specimens from 151 patients who had undergone potentially curative surgery for adenocarcinoma of the colon. Polymerase chain reaction (PCR) was used to assess allelic loss of five chromosome 18q microsatellite markers in the tumors. The relationship between allelic loss and disease-free and disease-specific survival was investigated. RESULTS: LOH was detected in 67 of 126 tumors. Chromosome 18q allelic loss was a negative prognostic indicator of both disease-free (relative risk [RR], 1.65; P = .01) and disease-specific survival (RR, 2.0; P = .003). 18q loss was also associated with significantly reduced disease-free and disease-specific survival in patients with stage II (P = .05 and P = .0156) and III (P = .038 and P = .032) disease. CONCLUSION: Chromosome 18q allelic loss is a prognostic marker in colorectal cancers. Chromosome 18 LOH studies may be useful in identifying patients with stage II disease who are at high risk for recurrence, and as such might benefit from adjuvant chemotherapy.

Adenocarcinoma↗
PubMed1997

Novel germline RET proto-oncogene mutations associated with medullary thyroid carcinoma (MTC): mutation analysis in Japanese patients with MTC.

Germ-like and somatic mutations in the RET proto-oncogene are associated with inherited and sporadic medullary thyroid carcinoma (MTC). The majority of patients with multiple endocrine neoplasia type 2A (MEN2A) and familial medullary thyroid carcinoma (FMTC) carry germ-line point mutations that result in the substitution of one of five cysteine residues. We investigated exons 10, 11, 13, 14 and 16 of the RET proto-oncogene in 33 unrelated Japanese patients with MTC. Eleven of the 33 cases (33%) were found to have germ-line mutations. Three previously unreported mutations in exon 10 and 11 were identified: one in codon 620, (TGC-->GGC), resulting in a cysteine to glycine substitution, and two in codon 630, (TGC-->TCC) and (TGC-->TAC), resulting in cysteine to serine and cysteine to tyrosine changes, respectively. The new mutations were present in the germ-line DNA of four unrelated patients for whom a family history of MTC had not been documented. Because the new RET alleles described here involve cysteine residues in a region of protein previously associated with FMTC and MEN2A, it is very likely that they represent mutations that predispose to the development of MTC.

Adolescent↗
PubMed1997

Mutations in MLH1 are more frequent than in MSH2 in sporadic colorectal cancers with microsatellite instability.

The microsatellite instability that is a feature of tumors in patients with hereditary nonpolyposis colorectal cancer (HNPCC) is a consequence of defective DNA mismatch repair. Mutations in the DNA mismatch repair genes MSH2 and MLH1 may account for up to 90% of HNPCC kindreds. Microsatellite instability is also seen in 10-16% of sporadic colorectal cancers. A limited number of MSH2 and MLH1 mutations have been described for sporadic colorectal cancers. In this study, we screened 12 primary sporadic colorectal cancers with microsatellite instability for mutations in MSH2 and MLH1 by using reverse transcription-polymerase chain reaction (RT-PCR) and single-strand-conformation-variant (SSCV) analysis. Eight mutations were identified in six tumors. One mutation in MLH1 was found to be present in the patient's germline DNA. Four tumors had somatic mutations in MLH1, and, in two of these tumors, two different mutations were identified. A single tumor had a somatic MSH2 mutation. Our observations suggest that MLH1 is mutated more frequently than MSH2 in sporadic colorectal cancers with microsatellite instability.

Adaptor Proteins, Signal Transducing↗
PubMed1997

Mutational analysis of MLH1 and MSH2 in 25 prospectively-acquired RER+ endometrial cancers.

Mutations in the DNA mismatch repair (MMR) genes MLH1 and MSH2 have been linked to several human cancers which display the replication error (RER) phenotype. Germline mutations in these two genes have been implicated in about 90% of families with hereditary nonpolyposis colorectal cancer (HNPCC). A significant proportion of endometrial cancers, the second most common malignancy of the HNPCC syndrome, also exhibit RER. We screened 125 primary endometrial adenocarcinomas with seven microsatellite markers and identified 25 specimens with RER (20%). We used single-strand conformation variant analysis to search for mutations in MLH1 and MSH2. Direct sequencing of variants revealed only one germline mutation in MLH1 and a single somatic mutation in MSH2. However, six previously unreported sequence polymorphisms in MLH1 were identified. Four of these polymorphisms show clear population-based differences in allele frequency. In addition, a highly informative marker for MLH1 was characterized. The low frequency of mutations in MLH1 and MSH2 in this large series of cancers suggests that other MMR genes are responsible for the RER phenotype in endometrial cancers.

Adaptor Proteins, Signal Transducing↗
PubMed1997

Differential display in primary and metastatic medullary thyroid carcinoma.

Despite recent advances in the understanding of the role of the RET proto-oncogene in the development of familial and approximately 30% of sporadic medullary thyroid carcinomas (MTC), little is known about other genetic events that modify the course and outcome of the disease. We compared the expression of genes in intrathyroidal MTCs to autologous local lymph node metastases by means of mRNA differential display (DDRT-PCR). This is the first report of differential display using surgical specimens of a primary cancer and its metastases. Total RNA was extracted from tumor tissue of two patients with MTC associated with multiple endocrine neoplasia (MEN 2B) and sporadic MTC, respectively. Following reverse transcription (RT), the products were PCR-amplified and separated on a denaturating polyacrylamide gel. RT-PCR products demonstrating differential expression were reamplified and used as probes for Northern blot analysis. Six fragments for which differential expression was confirmed were cloned and sequenced. Resultant sequences were tested for homology to sequences in public data bases, and two novel MTC-derived fragments (MDF-1, MDF-2) were identified. Sensitivity of the method was confirmed by identification of a sequence encoding the calcitonin precursor flanking peptide which is expressed almost exclusively in MTC and normal thyroid C cells. Overexpression of the ribosomal genes S3a and P0 was found in the metastases. Recent reports suggest that components of the translational apparatus act as regulatory mediators of growth, proliferation, and neoplastic change. The altered expression of ribosomal proteins and gene products encoded by MDF-1 or MDF-2 may play an important role in the progression and metastatic spread of MTC.

Blotting, Northern↗
PubMed1997

Prognostic value of chromosome 1p allelic loss in colon cancer.

BACKGROUND & AIMS: Current evidence suggests that there may be a tumor-suppressor gene on chromosome 1p associated with colorectal cancer. The aim of the present study was to determine whether allelic loss on chromosome 1p is of prognostic value in colorectal cancer. METHODS: Polymerase chain reaction was used to assess allelic loss of five chromosome 1p microsatellite markers in tumor specimens. Genomic DNA was prepared from archival tumor and corresponding normal tissue specimens from 116 patients who had undergone curative treatment for adenocarcinoma of the colon. Allelic loss was correlated with disease-free interval and survival. RESULTS: Deletion of 1p sequence was detected in 22 of 82 tumors. Deletions of the microsatellite markers D1S228 (1p36) and HY-TM1 (1p32) were significantly associated with poor survival (P < 0.05): relative risk, 4.1; 95% confidence interval, 1.25-9.23 for D1S228; and relative risk, 6.6; 95% confidence interval, 1.4-19 for HY-TM1. Loss of heterozygosity at D1S228 was also associated with shorter disease-free interval: relative risk, 4.5; 95% confidence interval, 1.3-11. CONCLUSIONS: Allelic loss in the 1p36 and 1p32 regions of chromosome 1 appears to be an independent predictor of poor prognosis in patients with adenocarcinoma of the colon.

Adult↗
PubMed1997

"Cold" single-strand conformational variants for mutation analysis of the RET protooncogene.

BACKGROUND: RET protooncogene mutation analysis is a routinely performed predictive DNA test in kindreds affected by multiple endocrine neoplasia (MEN) types 2A and 2B and familial medullary thyroid carcinoma (FMTC), and is a valuable diagnostic tool in newly diagnosed cases of medullary thyroid carcinoma (MTC). METHODS: We tested the suitability of the recently introduced "cold" single-strand conformational variant (SSCV) technique, which promises rapid, simple, nonradioactive detection of sequence variants in the identification of germline and somatic RET mutations. A total of 11 different mutations in exon 10 (codons 609, 611, 618, and 620) and 6 mutations in exon 11 (codon 634) were studied. RESULTS: Conditions were optimized so that conformational variants were demonstrated for all mutations examined in a single setting for exons 10 and 11. A novel six base pair (bp) inframe deletion between cysteines 630 and 634 was detected in a sporadic MTC. This adds to the evidence that not only cysteine deletions and substitutions but also changes in the spacing between cysteine residues have a pathogenic effect. CONCLUSIONS: Our results indicate that the cold SSCV method offers the advantages of simplicity, time savings, and nonradioactive detection for screening for RET sequence variants in hereditary and sporadic MTCs.

Amino Acid Sequence↗
PubMed1997

Hereditary motor and sensory neuropathy IIB: clinical and electrodiagnostic characteristics.

Axonal forms of autosomal dominant hereditary motor and sensory neuropathies (HMSNs) represent a heterogeneous group of disorders based on genetic linkage studies. We recently identified one large family with axonal HMSN exhibiting linkage to chromosome 3q, designated HMSN IIB, and report here the clinical and electrodiagnostic features. We clinically evaluated 10 individuals with HMSN IIB and performed detailed electrophysiologic studies in 5 of these patients. HMSN IIB is characterized clinically by the presence of distal symmetric motor weakness and prominent sensory loss affecting the lower extremities with preserved ankle reflexes. Symptomatic age at onset is in the second or early third decade of life. Six patients with HMSN IIB had distal trophic ulcerations in the feet, leading to eventual toe amputations in four cases. Electrodiagnostic studies confirmed a distal sensorimotor axonopathy involving the lower limbs with normal motor conduction velocities. Tibial H-reflexes were preserved in HMSN IIB, despite the uniform loss of sural nerve potentials. Overall, individuals with HMSN IIB demonstrated a consistent clinical and electrodiagnostic phenotype that had no overlap with genetically unaffected family members. The identification of specific clinical and electrodiagnostic features of HMSN IIB may prove useful in the diagnosis and differentiation between various subtypes of HMSN II.

Adult↗
PubMed1997

Allelotype of follicular thyroid carcinomas reveals genetic instability consistent with frequent nondisjunctional chromosomal loss.

Numerous studies aimed at the identification of chromosomal regions that are frequently deleted in specific tumor types have pointed to the location and involvement of specific tumor suppressor genes. Previous studies of loss of heterozygosity (LOH) among thyroid tumors have revealed frequent allelic deletions at a few chromosomal regions. A systematic genome-wide examination of LOH in a substantial number of follicular carcinomas, however, has not been performed previously. We assessed LOH at polymorphic markers from each nonacrocentric autosomal arm in a panel of 28 follicular thyroid carcinoma tumor and normal pairs. In contrast to the results of previous allelotype studies, we found high rates of LOH at multiple chromosomal regions. The highest rate of loss in our study was at 2p (50.0%), and 2q (50.0%), and the mean rate of LOH was 20.4%. Marked genetic instability in a subset of tumors was demonstrated by high fractional allelic loss, which accounted for more than 80% of observed LOH in this study. High fractional allelic loss was significantly associated with oxyphilic features and poor differentiation of these tumors. Our data provide evidence of a prevalent phenotype of nondisjunctional whole chromosomal loss in follicular thyroid carcinomas.

Adenocarcinoma, Follicular↗
PubMed1996

Allelotype analysis of esophageal adenocarcinomas: evidence for the involvement of sequences on the long arm of chromosome 4.

The incidence of esophageal adenocarcinoma has increased dramatically over the past 20 years. The causes for this change in incidence and the genetic defects that underlie tumorigenesis are unknown. We performed loss of heterozygosity (LOH) studies in esophageal adenocarcinomas in an effort to map the location of tumor suppressor genes involved in the initiation or progression of this cancer. A genome-wide search for LOH was undertaken using microsatellite repeat polymorphisms and a panel of 27 tumor and matched normal DNAs. This is the first report of an allelotype analysis of esophageal adenocarcinomas. We observed frequent loss of sequences on the short arm of chromosome 17 in the region of the TP53 gene. We also identified a region on 4q lost in more than half of the tumors investigated. The high rate of LOH for 4q sequences speaks to the involvement of an as yet unidentified tumor suppressor gene in esophageal adenocarcinoma tumorigenesis.

Adenocarcinoma↗
PubMed1996

Mxi1 tumor suppressor gene is not mutated in primary pancreatic adenocarcinoma.

Amplification of the c-myc oncogene occurs in a variety of solid tumors, including pancreatic adenocarcinomas. The MXI1 gene, located at 10q24-q25, may serve to negatively regulate c-myc oncogene activity, and potentially has tumor suppressor function. As such, altered MXI1 function might contribute to tumorigenesis. We examined 40 primary human pancreatic adenocarcinomas for MXI1 mutations. Single-strand conformation variant analysis and direct sequencing of the variants revealed a MXI1 polymorphism in 1 of 40 tumors. No MXI1 mutations were identified. Southern blot analyses did not reveal any gross rearrangements of MXI1. These results suggest that MXI1 is unlikely to play a role in human pancreatic adenocarcinoma tumorigenesis.

Adenocarcinoma↗
PubMed1996

Infrequent CDKN2 mutation in human differentiated thyroid cancers.

We examined the frequency of cyclin-dependent kinase (CDK) N2 alterations in differentiated and anaplastic thyroid cancers to assess the involvement of CDKN2 in the development of these cancers. The CDKN2 gene, which encodes the cell-cycle regulator p16, was recently shown to be mutated or deleted in many tumor cell lines. Its role in the genesis of primary tumors is uncertain, however. Tumor and corresponding normal DNAs were prepared by microdissection of paraffin-embedded tissue blocks or from frozen surgical specimens of 15 papillary, 15 follicular, and five anaplastic thyroid carcinomas. The entire CDKN2 coding region was screened by single-strand conformational variant analysis and direct sequencing of variants. The presence of homozygous deletions was evaluated by multiplex polymerase chain reaction (PCR) analysis. Loss of heterozygosity (LOH) in the CDKN2 region was assessed by using flanking polymorphic markers. Two somatic missense mutations were found among the 35 thyroid cancers, one in a follicular tumor and one in an anaplastic tumor. Multiplex PCR suggested the presence of homozygous deletion in one anaplastic tumor and hemizygous deletions in four tumors. LOH studies revealed loss of 9p sequences in four follicular (27%) and two anaplastic (50%) cancers. Our data suggest that alterations in CDKN2 played a role in a minority of thyroid cancers (three of 35). LOH in the region of CDKN2 is seen in a significant proportion of follicular and anaplastic but not papillary cancers. Loss of 9p sequences suggests a role for a tumor suppressor gene in the development of follicular and anaplastic thyroid cancers.

Adenocarcinoma, Follicular↗
PubMed1996

Loss of heterozygosity of chromosome 3p sequences is an infrequent event in endometrial cancer.

The genetic events associated with endometrial cancer are at present poorly understood. Frequent loss of heterozygosity (LOH) in a particular chromosomal region is often indicative of the involvement of a tumor suppressor gene. Previous studies are in disagreement over the involvement of a tumor suppressor gene(s) on the short arm of chromosome 3 in endometrial tumorigenesis. A set of 75 endometrial carcinomas was examined for the presence of LOH using 10 microsatellite repeat polymorphisms which are localized to chromosome 3p. In addition, these tumors were examined for the presence of replication errors (RER). Eleven of the 64 RER-negative tumors (17.2%) displayed LOH at one or more loci on chromosome 3p. The highest frequency of LOH at a single marker was 10.8% (4/37) at the locus D3S1312. The tumors investigated did not suggest that there was any common region of deletion. There was a significant increase in the frequency of 3p LOH in high-grade versus low-grade endometrioid adenocarcinomas (P < 0.05). Our results indicate that it is unlikely that a tumor suppressor gene on the short arm of chromosome 3 plays a major role in endometrial tumorigenesis.

Alleles↗
PubMed1996

Frequent deletion of chromosome 1p sequences in an aggressive histologic subtype of endometrial cancer.

The molecular genetic events underlying endometrial tumorigenesis are ill-defined at present. We have identified a region on the short arm of chromosome 1 which is frequently deleted in endometrial cancers. The region of deletion has been localized to bands 1p32-33. Deletion of 1p32-33 is seen more frequently in cancers of the highly aggressive papillary serous type than in cancers of the less-aggressive endometrioid type. These data suggest the presence of a tumor suppressor gene on 1p32-33 which is specifically involved in the development of endometrial cancers with poor outcome.

Adenocarcinoma, Clear Cell↗