[Evaluation of Apolipoprotein A1 and Posttranslationally Modified Forms of Transthyretin as Biomarkers for Ovarian Cancer Detection in an Independent Study Population]
Ciphergen put out a PR about this, saying it validates results of the the study this post references. The difference being that this tests against disease controls, not those of healthy ones, which is good, but . . . Stock has been on a steady down trend ever since, and is below a buck this morning. All the studies in the world aren't going to help unless Quest says something about launching the blasted test.
>>Cancer Epidemiology Biomarkers & Prevention Vol. 15, 1641-1646, September 2006
Evaluation of Apolipoprotein A1 and Posttranslationally Modified Forms of Transthyretin as Biomarkers for Ovarian Cancer Detection in an Independent Study Population
Lee E. Moore1, Eric T. Fung2, Marielena McGuire2, Charles C. Rabkin1, Annette Molinaro1, Zheng Wang2, Fujun Zhang2, Jing Wang2, Christine Yip2, Xiao-Ying Meng2 and Ruth M. Pfeiffer1
1 Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Department of Health and Human Services, Bethesda, Maryland and 2 Ciphergen Biosystems, Inc., Fremont, California
Requests for reprints: Lee E. Moore, Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, 6120 Executive Boulevard, EPS 8118, Bethesda, MD 20852-7240. Phone: 301-496-6427; Fax: 301-402-1819. E-mail: moorele@mail.nih.gov
Background: Although overall 5-year survival rates for ovarian cancer are poor (10-30%), stage I/IIa patients have a 95% 5-year survival. New biomarkers that improve the diagnostic performance of existing tumor markers are critically needed. A previous study by Zhang et al. reported identification and validation of three biomarkers using proteomic profiling that together improved early-stage ovarian cancer detection.
Methods: To evaluate these markers in an independent study population, postdiagnostic/pretreatment serum samples were collected from women hospitalized at the Mayo Clinic from 1980 to 1989 as part of the National Cancer Institute Immunodiagnostic Serum Bank. Sera from 42 women with ovarian cancer, 65 with benign tumors, and 76 with digestive diseases were included in this study. Levels of various posttranslationally forms of transthyretin and apolipoprotein A1 were measured in addition to CA125.
Results: Mean levels of five of the six forms of transthyretin were significantly lower in cases than in controls. The specificity of a model including transthyretin and apolipoprotein A1 alone was high [96.5%; 95% confidence interval (95% CI), 91.9-98.8%] but sensitivity was low (52.4%; 95% CI, 36.4-68.0%). A class prediction algorithm using all seven markers, CA125, and age maintained high specificity (94.3%; 95% CI, 89.1-97.5%) but had higher sensitivity (78.6%; 95% CI, 63.2-89.7%).
Conclusions: We were able to replicate the findings reported by Zhang et al. in an independently conducted blinded study. These results provide some evidence that including age of patient and these markers in a model may improve specificity, especially when CA125 levels are 35 units/mL. Influences of sample handling, subject characteristics, and other covariates on biomarker levels require further consideration in discovery and replication or validation studies.<<
Cheers, Tuck |
