Gregory C Critchfield

Myriad Genetics, Salt Lake City, Utah, United States

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Publications (5)25.65 Total impact

  • Thomas S Frank, Gregory C Critchfield
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    ABSTRACT: The characterization of specific genes responsible for the hereditary risk of common cancers has enabled the development of clinical tests designed to identify at-risk individuals and to significantly improve the clinical outcome of such individuals. Two of the most important syndromes associated with a hereditary risk of cancer in women are hereditary breast and ovarian cancer, resulting from the BRCA1 and BRCA2 genes, and hereditary non-polyposis colorectal cancer, caused primarily by the MLH1 and MSH2 genes. As testing for the hereditary risk of breast, ovarian, endometrial and colorectal cancer enters the clinical mainstream, physicians responsible for the health care of women are increasingly required to assess and provide guidance to healthy patients with a strong family history, cancer survivors who may be at risk of a second cancer and women who discover that a family member carries a specific mutation identified through genetic testing. Obstetricians and gynaecologists must therefore become familiar with the principles of assessing the family history for specific hereditary cancer syndromes, with the appropriate use of tests to confirm such syndromes and with the management options for women who have inherited a greatly increased risk of cancer.
    Bailli&egrave re s Best Practice and Research in Clinical Obstetrics and Gynaecology 11/2002; 16(5):703-13. · 2.02 Impact Factor
  • Thomas S Frank, Gregory C Critchfield
    Clinical Obstetrics and Gynecology 10/2002; 45(3):671-83; discussion 730-2. · 1.84 Impact Factor
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    ABSTRACT: To assess the characteristics that correlate best with the presence of mutations in BRCA1 and BRCA2 in individuals tested in a clinical setting. The results of 10,000 consecutive gene sequence analyses performed to identify mutations anywhere in the BRCA1 and BRCA2 genes (7,461 analyses) or for three specific Ashkenazi Jewish founder mutations (2,539 analyses) were correlated with personal and family history of cancer, ancestry, invasive versus noninvasive breast neoplasia, and sex. Mutations were identified in 1,720 (17.2%) of the 10,000 individuals tested, including 968 (20%) of 4,843 women with breast cancer and 281 (34%) of 824 with ovarian cancer, and the prevalence of mutations was correlated with specific features of the personal and family histories of the individuals tested. Mutations were as prevalent in high-risk women of African (25 [19%] of 133) and other non-Ashkenazi ancestries as those of European ancestry (712 [16%] of 4379) and were significantly less prevalent in women diagnosed before 50 years of age with ductal carcinoma in situ than with invasive breast cancer (13% v 24%, P =.0007). Of the 74 mutations identified in individuals of Ashkenazi ancestry through full sequence analysis of both BRCA1 and BRCA2, 16 (21.6%) were nonfounder mutations, including seven in BRCA1 and nine in BRCA2. Twenty-one (28%) of 76 men with breast cancer carried mutations, of which more than one third occurred in BRCA1. Specific features of personal and family history can be used to assess the likelihood of identifying a mutation in BRCA1 or BRCA2 in individuals tested in a clinical setting.
    Journal of Clinical Oncology 04/2002; 20(6):1480-90. · 18.04 Impact Factor
  • T S Frank, G C Critchfield
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    ABSTRACT: In the past, all women with a family history of breast or ovarian cancer were considered to be at increased risk of cancer themselves. The discovery of BRCA1 and BRCA2 demonstrated that susceptibility to breast and ovarian cancer can be inherited by women as a single-gene autosomal dominant disorder. For such women, evaluation of family history is an important screening tool to identify the possibility of hereditary cancer risk but only genetic testing can provide definitive, individualized risk assessment. Women who have inherited mutations in BRCA1 or BRCA2 now have several medical management options to address their increased risk of cancer. A well-educated community of health care providers and patients can use hereditary risk assessment, including genetic testing, to improve health care.
    Clinics in Perinatology 07/2001; 28(2):395-406. · 2.58 Impact Factor
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    ABSTRACT: Genetic testing for mutations in BRCA1 and BRCA2, two genes predisposing to breast and ovarian cancers, is available to women with a relevant family history. The aim of this study was to estimate the positive and negative predictive value of clinical sequence analysis of these genes. A reference graph showing positive and negative predictive values over a range of pre-test risk was derived, taking into account the sensitivity and specificity of a full-sequence analysis test. High positive and negative predictive values were found for women with pre-test risk between 4% and 40%, a range of risk commonly seen in clinical testing. The predictive value of full sequence and single-site analysis of BRCA1 and BRCA2, therefore, compares favorably with other diagnostic medical tests. Our results provide a numerical estimate of the predictive value of BRCA testing, and as such, provide a valuable tool to healthcare providers and families as they interpret BRCA1 and BRCA2 test results.
    Genetic Testing 02/2000; 4(1):45-8. · 1.17 Impact Factor