BRCA1 and BRCA2 mutations in women of different ethnicities undergoing testing for hereditary breast-ovarian cancer.

BACKGROUND: In women at increased risk for breast and ovarian cancer, the identification of a mutation in breast cancer gene 1 (BRCA1) and BRCA2 has important implications for screening and prevention counseling. Uncertainty regarding the role of BRCA1 and BRCA2 testing in high-risk women from diverse ancestral backgrounds exists because of variability in prevalence estimates of deleterious (disease-associated) mutations in non-white populations. In this study, the authors examined the prevalence of BRCA1 and BRCA2 mutations in an ethnically diverse group of women who were referred for genetic testing. METHODS: In this cross-sectional analysis, the prevalence of BRCA1 and BRCA2 mutations was assessed in a group of non-Ashkenazi Jewish women who underwent genetic testing. RESULTS: From 1996 to 2006, 46,276 women who met study criteria underwent DNA full-sequence analysis of the BRCA1 and BRCA2 genes. Deleterious mutations were identified in 12.5% of women, and recurrent deleterious mutations (prevalence >2%) were identified in all ancestral groups. Women of non-European descent were younger (mean age, 45.9 years; standard deviation [SD], 11.6 years) than European women (mean age, 50 years; SD, 11.9 years; P < .001). Women of African (15.6%; odds ratio [OR], 1.3 [95% confidence interval (95% CI), 1.1-1.5]) and Latin American (14.8%; OR, 1.2 [95% CI, 1.1-1.4]) ancestries had a significantly higher prevalence of deleterious BRCA1 and BRCA2 mutations compared with women of Western European ancestry (12.1%), primarily because of an increased prevalence of BRCA1 mutations in those 2 groups. Non-European ethnicity was associated strongly with having a variant of uncertain significance; however, reclassification decreased variant reporting (from 12.8%-->5.9%), and women of African ancestry experienced the largest decline (58%). CONCLUSIONS: Mutation prevalence was found to be high among women who were referred for clinical BRCA1 and BRCA2 testing, and the risk was similar across diverse ethnicities. BRCA1 and BRCA2 testing is integral to cancer risk assessment in all high-risk women.

Multiple endocrine neoplasia 2A due to a unique C609S RET mutation presents with pheochromocytoma and reduced penetrance of medullary thyroid carcinoma.

OBJECTIVE: We have identified a large kindred with multiple endocrine neoplasia 2A (MEN 2A) due to a mutation at RET codon 609 that results in a cysteine to serine substitution, a mutation previously identified in only one case in the literature. We characterized the clinical phenotype of the kindred and the biochemical mechanism of this new mutation. PATIENTS AND DESIGN: The index case, a 42-year-old woman, presented with pheochromocytoma. We screened 29 family members for the presence of the mutation. Of the 15 mutation-positive family members, 11 agreed to undergo further evaluation by physical examination, calcium and pentagastrin-stimulated calcitonin levels, measurement of urinary metanephrines, adrenal imaging and serum calcium levels. Biochemical characterization of the mutation was by transient transfection of human neuroblastoma cells and Western blot analysis. RESULTS: This kindred demonstrated an inheritance pattern consistent with autosomal dominant pheochromocytoma. Strikingly, no clinically evident case of medullary thyroid cancer (MTC) was observed among mutation-positive family members. Thyroidectomy in six cases revealed C-cell hyperplasia in all and microscopic MTC in two cases. Transfection experiments using human neuroblastoma cells showed that the mutant RET, unlike the wild-type receptor, is constitutively phosphorylated in the absence of ligand, and thus resembles other previously characterized MEN 2A mutations. CONCLUSIONS: The identification of a new mutation causing a MEN 2A phenotype that features pheochromocytoma and the surprising absence of clinically apparent MTC has significant implications for carriers of this mutation and provides further insights into the genotype-phenotype correlation in MEN 2A.

A novel method for creating artificial mutant samples for performance evaluation and quality control in clinical molecular genetics.

The lack of readily available, patient-derived materials for molecular genetic testing of many heterozygous or rare disorders creates a major impediment for laboratory proficiency and quality control procedures. The paucity of clinically derived mutation-positive samples could be surmounted if it were possible to construct artificial samples containing mutations of interest that would sufficiently resemble natural human samples. Such samples could then function as acceptable and realistic performance evaluation challenges and quality control reagents for recipient laboratories. Using the cystic fibrosis gene (CFTR) as a prototype, we have devised and executed experiments designed to generate unique DNA samples that could be used for these purposes. We used site-directed mutagenesis to generate mutations of interest in plasmid DNA derived from common bacterial artificial chromosome sources containing the cystic fibrosis transmembrane conductance receptor gene. CFTR mutations G85E and 1078delT were chosen to represent mutations in the original American College of Medical Genetics-recommended population-screening panel of 25 mutations. DNA samples containing predetermined concentrations and ratios of wild-type and mutated plasmids, bacterial artificial chromosomes of interest, and nonhuman genomic carrier DNA were characterized and tested in-house and in a group of nine pilot testing laboratories using a variety of technical platforms. The results indicate that these constructs, containing CFTR mutations in heterozygous and homozygous states, can serve as valid and accessible materials for quality assurance, including performance evaluation, proficiency testing, and assay quality control.

The relationship of APOE genotype to neuropsychological performance in long-term cancer survivors treated with standard dose chemotherapy.

PURPOSE: The primary purpose of this study was to compare the neuropsychological performance of long-term survivors of breast cancer and lymphoma treated with standard dose chemotherapy who carried the epsilon 4 allele of the Apolipoprotein E (APOE) gene to those who carry other APOE alleles. PATIENTS AND METHODS: Long-term survivors (mean=8.8+/-4.3 years post-treatment) of breast cancer (N=51, age=55.9+/-8.8) or lymphoma (N=29, age=55.8+/-11.6) who had been treated with standard-dose chemotherapy completed a standardized battery of neuropsychological and psychological tests. Survivors were also classified into two groups based on the presence (N=17) or absence (N=63) of at least one epsilon 4 allele of APOE. RESULTS: Analysis of covariance, controlling for age, gender, education, diagnosis, and WRAT-3 reading subtest (a proxy measure of baseline IQ), indicated that survivors with at least one epsilon 4 allele scored significantly lower in the visual memory (p<0.03) and the spatial ability (p<0.05) domains and tended to score lower in the psychomotor functioning (p<0.08) domain as compared to survivors who did not carry an epsilon 4 allele. No group differences were found on depression, anxiety, or fatigue. CONCLUSIONS: The results of this study provide preliminary support for the hypothesis that the epsilon 4 allele of APOE may be a potential genetic marker for increased vulnerability to chemotherapy-induced cognitive decline.

Factors affecting the detection rate of human papillomavirus.

BACKGROUND: Maximizing the accuracy of human papillomavirus (HPV) detection from a single sample is important for clinical and research purposes. The purpose of this study was to determine whether cyclic hormonal variation, recent sexual intercourse, interval between samplings, and the technique used to sample affect the detection of HPV. METHODS: This study was a prospective, longitudinal, randomized controlled trial. Three techniques for self-sampling (2 consecutive synthetic polyester fiber [Dacron] swabs, a single Dacron swab, and a tampon) were repeated at 3 different sampling times during a period of 4 to 6 weeks in addition to 1 clinician-directed sampling of the ectocervix and endocervix at the first sampling time. All self-samplings were taken in a proscribed randomized order. Women (aged 18 to 68 years) attending a colposcopy clinic for abnormal cytology or abnormal cervical appearance participated in the study. The outcome measure was the detection of HPV by polymerase chain reaction amplification. RESULTS: The 103 participants provided 1,189 cervicovaginal samplings. Logistic regression indicated that intercourse within 48 hours of sampling did not result in a greater detection of high-risk or any HPV type (odds ratio [OR] = 1.05, 95% confidence interval [CI], 0.65-1.69; OR = 1.08, 95% CI, 0.73-1.60, respectively). Among those women who have regular menstrual cycles, there was no cyclic effect on HPV detection for high-risk and any HPV types. Time from previous sampling did not affect HPV detection. Among the self-sampling techniques, using a single self-swab and the tampon resulted in the detection of HPV between 10% and 35% less often than using 2 consecutive swabs (P < .025). Self-sampling with 2 swabs was not significantly different from clinician sampling for detecting high-risk HPV types (OR for self-sampling = 0.87 (95% CI, 0.66-1.13)). CONCLUSIONS: HPV detection is not dependent on menstrual cycle timings, the recency of intercourse, or the time between samplings, but it is dependent on the sampling technique.

Tampon samplings with longer cervicovaginal cell exposures are equivalent to two consecutive swabs for the detection of high-risk human papillomavirus.

BACKGROUND: Self-sampling for human papillomavirus (HPV) is useful for triage of ASCUS Papanicolaou (Pap) smears. Tampons with 10-second cervicovaginal cell exposure can detect HPV but appear to be less efficient than two consecutive swabs. GOAL: The purpose of this study was to evaluate increased vaginal tampon exposures for detecting high-risk HPV. STUDY DESIGN: This longitudinal cohort study followed women who self-sampled weekly with tampons for progressively longer periods of time. A tampon was inserted for 10 seconds at the office visit and 1 hour, 4 hours, and overnight for the three subsequent home samples. Two concurrent swabs were used with each tampon sampling for contemporaneous comparisons. The MY09/MY11 PCR primer system with reverse line blot detection strips was used to detect 18 distinct high-risk HPV types. RESULTS: Of the 309 tampons and 618 swabs used at home, 83% were returned. Among normal women, the 10-second tampon detected fewer with normal histology and high-risk HPV than did its swabs ( = 0.0412), but the 1-hour, 4-hour, and overnight tampons had high-risk-HPV detection rates equal to their swabs. In women with CIN, all tampons and swabs equally identified those with high-risk HPV. CONCLUSION: Self-sampling for HPV detection is acceptable, feasible, and technically accurate for both tampons with longer cervicovaginal exposures and swabs. The choice of technique is dependent on the woman, her culture, and her clinician.

Randomized clinical trial of PCR-determined human papillomavirus detection methods: self-sampling versus clinician-directed--biologic concordance and women's preferences.

OBJECTIVE: The purpose of this study was to compare the high-risk human papillomavirus detection rates from self-sampled swabs and tampons with standard clinician-directed speculum sampling and to assess women's acceptance of self-sampling methods. STUDY DESIGN: One hundred three women who required a colposcopy underwent order randomization of the human papillomavirus sampling technique. Kappa and McNemar test statistical results were used to measure the agreement between clinician-directed and self-sampling techniques for high-risk types of human papillomavirus and the acceptance of self-sampling techniques. RESULTS: All self-directed samplings were equivalent to clinician sampling for all cervical intraepithelial neoplasia disease states. High-risk human papillomavirus was detected by self- and clinician-directed methods in 83% of the women with cervical intraepithelial neoplasia, grade 2/3. The 2 sequential swabs trend toward better detection of high-risk types of human papillomavirus than all other techniques for women with normal histologic factors (P =.0736, by McNemar's chi2 test). Ninety-four percent of women would accept self-sampling for their yearly cervical screen. CONCLUSION: Self-sampling is equivalent to clinician sampling for the detection of high-risk human papillomavirus and is acceptable to women as a yearly screen.