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Julie M Cunningham

Publications and source records attributed to Julie M Cunningham.

26 records · Page 2Linked to original sources
PubMed2003

No association of germline alteration of MSR1 with prostate cancer risk.

The macrophage scavenger receptor 1 gene (MSR1) was recently identified as a candidate susceptibility gene for hereditary prostate cancer and as a risk factor for sporadic prostate cancer. To confirm these findings, we screened MSR1 for germline mutations among individuals with familial prostate cancer and tested gene variants for associations in both sporadic and familial prostate cancer. Our results do not support MSR1 as a risk factor for prostate cancer.

Aged↗
PubMed2003

BRAF mutations in colon cancer are not likely attributable to defective DNA mismatch repair.

Frequent BRAF mutations were reported recently in a variety of human malignancies, including colorectal cancer. In this study, we screened 293 colorectal cancers for mutations in exons 11 and 15, two regions containing hotspots for BRAF mutation. Of the 293 cancers, 170 had normal mismatch repair, and 123 had defective mismatch repair (originating from both somatic as well as germ-line mutations in several of the mismatch repair genes). A total of 63 exonic mutations (22%) were detected, 60 of which were V599E, and one each of D593G, G468E, and D586A. Of the tumors with defective mismatch repair, 34% (42 of 123) had a mutation in BRAF, whereas only 12% (21 of 170) of tumors with proficient mismatch repair demonstrated a mutation (P < 0.0001). Interestingly, BRAF mutations were found most often in cases with an hMHL1 abnormality (35 of 60) and rarely in cases with an hMSH2 abnormality (1 of 39; P < 0.0001). More interestingly, of the 31 hMLH1 cases with a BRAF mutation, 30 occurred in tumors known to have hypermethylation of hMLH1 promoter. Only 1 of the 15 cases with a germ-line mutation in hMLH1 had a mutation in BRAF. In this series, BRAF mutations occurred rarely in tumors with defective mismatch repair attributable to the presence of germ-line mutation in either hMLH1 or hMSH2. Furthermore, BRAF mutations were strongly associated with the epigenetic alteration of hMLH1. Overall, these data suggest that BRAF mutations are not a consequence of defective mismatch repair per se.

Adaptor Proteins, Signal Transducing↗
PubMed2003

Luteinizing hormone beta polymorphism and risk of familial and sporadic prostate cancer.

BACKGROUND: Circulating testosterone plays an important role in maintenance and growth of prostate cells. Luteinizing hormone (LH), secreted from the anterior pituitary, signals testicular Leydig cells to secrete testosterone. A genetic variant of the LH-beta protein, LH-betaV, exists in up to 40% of Caucasians and is more bioactive than the wild-type protein. We hypothesized that genetically determined variation in LH function might affect susceptibility to prostate cancer via altered testosterone secretion. METHODS: We determined the frequency of the LH-betaV polymorphism (two linked polymorphisms: Trp(8) --> Arg and Ile(15) --> Thr) in familial prostate cancer patients (n = 446), in sporadic prostate cancer patients (n = 388), and in population-based controls without prostate cancer (n = 510) to assess the role of this polymorphism in susceptibility to prostate cancer. RESULTS: A higher frequency of this variant genotype (LH-betaV: Arg(8)/Thr(15)) was observed in familial prostate cancer patients (18.6%) than in controls (13.7%), and after taking into account the correlation of the familial cases and adjusting for age and body mass index (BMI), there was a weak positive association between the variant LH-beta genotype, and risk of familial prostate cancer (OR = 1.29; 95% CI 0.96-1.75). The sporadic case group was also slightly more likely to have a variant genotype (15.2%) compared to the controls (13.7%), and after adjustment for age and BMI, a similar association with this variant was found (OR = 1.33; 95% CI 0.86-02.07). Surgical cases showed a slightly stronger association for the variant LH-beta genotype compared to non-surgical cases, but among the surgical cases there was little variability in risk across nodal status, stage, and tumor grade. CONCLUSIONS: These data are consistent with the hypothesis that the LH-beta variant is a weak risk factor for prostate cancer.

Adult↗
PubMed2003

Mutations in CHEK2 associated with prostate cancer risk.

The DNA-damage-signaling pathway has been implicated in all human cancers. However, the genetic defects and the mechanisms of this pathway in prostate carcinogenesis remain poorly understood. In this study, we analyzed CHEK2, the upstream regulator of p53 in the DNA-damage-signaling pathway, in several groups of patients with prostate cancer. A total of 28 (4.8%) germline CHEK2 mutations (16 of which were unique) were found among 578 patients. Additional screening for CHEK2 mutations in 149 families with familial prostate cancer revealed 11 mutations (5 unique) in nine families. These mutations included two frameshift and three missense mutations. Importantly, 16 of 18 unique CHEK2 mutations identified in both sporadic and familial cases were not detected among 423 unaffected men, suggesting a pathological effect of CHEK2 mutations in prostate cancer development. Analyses of the two frameshift mutations in Epstein Barr virus-transformed cell lines, using reverse-transcriptase polymerase chain reaction and western blot analysis, revealed abnormal splicing for one mutation and dramatic reduction of CHEK2 protein levels in both cases. Overall, our data suggest that mutations in CHEK2 may contribute to prostate cancer risk and that the DNA-damage-signaling pathway may play an important role in the development of prostate cancer.

Age of Onset↗
PubMed2002

Analysis of the RNASEL gene in familial and sporadic prostate cancer.

The RNASEL gene on chromosome 1q25 was recently identified as a candidate gene for hereditary prostate cancer (PC). To confirm these findings, we screened 326 patients from 163 families with familial PC for potential germline mutations, by use of conformation-sensitive gel electrophoresis, followed by direct sequence analysis. A total of six variants were identified, including one intronic and five exonic changes (three missense and two silent alterations). There were no unequivocal pathogenic changes. To further test for potential associations between genes and increased risk for disease, the three missense polymorphisms (Ile97Leu, Arg462Gln, and Glu541Asp) were genotyped in 438 patients with familial PC and in 510 population-based control subjects. Association testing revealed no significant differences between patients and control subjects for either the Leu97 variant (chi(2) trend test = 1.42; P=.23) or the Asp541 variant (chi2=1.52; P=.22). However, significant differences were detected for the Arg462Gln genotypes (chi2=5.20; P=.02; odds ratio [OR] = 0.54; 95% confidence interval [CI] 0.32-0.91) when the genotype Gln/Gln was compared with Arg/Arg. In subset analyses, associations were also observed in the younger group (age at diagnosis </=64 years) (P=.0008; OR=0.29; 95% CI = 0.13-0.66), in node-negative patients (P=.01; OR=0.48; 95% CI 0.27-0.84), patients with stage T(1)/T(2) disease (P=.008; OR=0.39; 95% CI 0.2-0.75), and patients with low-grade disease (P=.01; OR=0.40; 95% CI 0.20-0.78). To evaluate whether this variant was also associated with sporadic PC, we genotyped an additional 499 patients with sporadic PC. Differences in frequency were not detected between patients with sporadic disease and control subjects. However, the same association was observed between patients with familial disease and patients with sporadic disease for the entire group (chi2=4.82; P=.03), as well as in the subset analyses. These results suggest that polymorphic changes within the RNASEL gene may be associated with increased risk of familial but not sporadic PC.

Adult↗
PubMed2002

Immunohistochemistry versus microsatellite instability testing in phenotyping colorectal tumors.

PURPOSE: To compare microsatellite instability (MSI) testing with immunohistochemical (IHC) detection of hMLH1 and hMSH2 in colorectal cancer. PATIENTS AND METHODS: Colorectal cancers from 1,144 patients were assessed for DNA mismatch repair deficiency by two methods: MSI testing and IHC detection of hMLH1 and hMSH2 gene products. High-frequency MSI (MSI-H) was defined as more than 30% instability of at least five markers; low-level MSI (MSI-L) was defined as 1% to 29% of loci unstable. RESULTS: Of 1,144 tumors tested, 818 showed intact expression of hMLH1 and hMSH2. Of these, 680 were microsatellite stable (MSS), 27 were MSI-H, and 111 were MSI-L. In all, 228 tumors showed absence of hMLH1 expression and 98 showed absence of hMSH2 expression: all were MSI-H. CONCLUSION: IHC in colorectal tumors for protein products hMLH1 and hMSH2 provides a rapid, cost-effective, sensitive (92.3%), and extremely specific (100%) method for screening for DNA mismatch repair defects. The predictive value of normal IHC for an MSS/MSI-L phenotype was 96.7%, and the predictive value of abnormal IHC was 100% for an MSI-H phenotype. Testing strategies must take into account acceptability of missing some cases of MSI-H tumors if only IHC is performed.

Aged↗
PubMed2002

The gene mutated in autosomal recessive polycystic kidney disease encodes a large, receptor-like protein.

Autosomal recessive polycystic kidney disease (ARPKD) is characterized by dilation of collecting ducts and by biliary dysgenesis and is an important cause of renal- and liver-related morbidity and mortality. Genetic analysis of a rat with recessive polycystic kidney disease revealed an orthologous relationship between the rat locus and the ARPKD region in humans; a candidate gene was identified. A mutation was characterized in the rat and screening the 66 coding exons of the human ortholog (PKHD1) in 14 probands with ARPKD revealed 6 truncating and 12 missense mutations; 8 of the affected individuals were compound heterozygotes. The PKHD1 transcript, approximately 16 kb long, is expressed in adult and fetal kidney, liver and pancreas and is predicted to encode a large novel protein, fibrocystin, with multiple copies of a domain shared with plexins and transcription factors. Fibrocystin may be a receptor protein that acts in collecting-duct and biliary differentiation.

Adult↗