Abstract P2-10-05: Referral to Genetic Services (GS) and Mutation Yield in 1132 Individuals at Risk for Hereditary Breast Ovarian Cancer Syndromes (HBOC)

Background: Family history directs referral of unaffected individuals to GS and is the main strategy to identify hereditary breast ovarian cancer syndrome. In unaffected individuals with known familial mutations, potentially life saving information can be provided to a large number of these individuals at a very modest cost.

Objectives: 1) To determine the rate of deleterious mutations in high risk individuals, based on pedigree, and 2) to identify the origin of their referral. Methods:

Over a 5-year period (2004 -2009) we analyzed the source of referral for genetic testing and the mutations detected in 1132 consecutively tested individuals. Of 1132 patients tested for BRCA1 or BRCA2 mutations, 420 were unaffected by cancer and 712 had breast or ovarian cancer at the time consultation. We excluded those from families who were previously tested at our institution to limit the bias for mutation positivity.

Results:

Seven hundred and sixty five patients were tested via comprehensive BRCA analysis (63 patients also had BART analysis) and of those only 7% (55) had deleterious mutations. Only 3% (24) had mutations in BRCA1 gene, and 29 patients had deleterious mutations in BRCA2. Of the 63 patients who underwent BART only 3% (2) had large deletions in BRCA1 gene. Two hundred and seventy three patients were tested for the three known Ashkenazi mutations and 20% (57) had deleterious mutations 10% (28) in BRCA1 gene and 10% (29) in BRCA 2. Ninety four patients were tested for known family mutations with single site analysis and there were (57%) 54 had deleterious mutations 27% (26) in BRCA 1 gene and 29% (28) in BRCA 2. Referring source was: self 283 (25%), GYN 430 (38%), surgeon 283 (25%), PCP 136 (12%) cases. Conclusions:

Single site testing of a known mutation costs ∼ 400$ and in 94 patients (8%) gave rapid information about cancer risk. Of these 27% (26) unaffected individuals were identified as carrying deleterious mutations and 73% (68) individuals found out their cancer risk was average. The yield of testing by comprehensive BRCA analysis was 7%, M3 panel detected 20% deleterious mutation and single site analysis for known familial mutations had the lower cost and higher yield of 57%. Primary care physicians identified only 12% of patients with high risk for hereditary cancer syndromes.

Discussion:

Although family history is the cornerstone of high-risk patient referral to GS, primary care physicians referred only 12% of all patients at risk for HBOC. Attention to family history and increased public awareness of hereditary risk are effective means of identifying at risk populations for referral for GS. The yield of mutation detection is highest and cost effective in families with known mutations. Our yield of 57% detection in families with known mutations is likely an indication that not all family members at risk seek genetic counseling or are referred at the same center.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-10-05.

Retinoid signaling directs secondary lineage selection in pancreatic organogenesis

BACKGROUND/PURPOSE

Retinoid signaling plays an important role in many differentiation pathways. Retinoid signaling has been implicated in the induction of differentiation by pancreatic ductal cancer cell lines and in patients with pancreatic cancer. The authors wished to better understand the role of retinoid signaling in pancreatic development.

METHODS

Embryonic pancreas was harvested from mice at serial gestational ages and immunohistochemical analysis was performed for retinoic acid receptors (RAR-alpha, RAR-beta, RAR-gamma), and retinoid X receptors (RXR-alpha, RXR-beta, and RXR-gamma). Also, early embryonic pancreases were cultured for 7 days with exogenous 9-cis retinoic acid (9cRA) or all-trans retinoic acid (atRA) and analyzed histologically and immunohistochemically.

RESULTS

Retinoid receptors were expressed in a lineage-specific distribution, with stronger expression for many in the exocrine compartment. The receptors were not often expressed until late gestation. Exogenous 9cRA induced predominantly ducts instead of acini, plus more mature endocrine (islet) architecture. Exogenous atRA induced predominantly acini instead of ducts, with no apparent endocrine effect.

CONCLUSIONS

Retinoids may have an important role in pancreatic differentiation, with a particular effect on secondary lineage selection between ductal and acinar phenotype. Because the control of ductal versus acinar differentiation has been implicated strongly in the pathogenesis of pancreatic ductal carcinoma, these results may lay the groundwork for studies in the mechanism of induced differentiation of pancreatic ductal cancer by retinoids.

Glottal patency during experimental seizures in piglets

Tracheostomized cats and piglets demonstrate respiratory stimulation during experimental seizures, whereas airway intact piglets demonstrate hypoventilation and increased subglottic resistances. The purpose of this study was to characterize the role of the vocal folds in contributing to these increased subglottic resistances during experimental seizures. A controlled animal study was performed in six anesthetized, spontaneously breathing, hyperoxic piglets who had subglottic pressure and airflow measured. A fiberoptic video scope directed into the cephalad trachea recorded subglottic images of the vocal folds. Glottal area patency (GAP) was evaluated at inspiratory onset (Io), peak inspiratory pressure (Ip), and expiratory onset (Eo) for four to five consecutive breaths under baseline control, ictal, interictal, and anticonvulsant conditions. Seizures were induced with i.v. pentylenetetrazol or bicuculline. Normalized GAP was greatest at Ip under all conditions, except anticonvulsant. During ictal periods, piglets demonstrated significant reductions in mean GAP throughout the respiratory cycle (Io, 98%; Ip, 78%; Eo, 98%), compared with baseline (p < 0.001, repeat measures analysis of variance). During ictal discharges, hypoventilation and glottal obstruction resulted in significant reductions in mean arterial pH (-0.35) and PaO2 (-39 kPa) and elevations in PaCO2 (+8.1 kPa), compared with baseline conditions. During interictal conditions mean GAP at Ip was increased, whereas at Eo (-66%) GAP was reduced, compared with control. These data demonstrate that the vocal folds are tonically adducted throughout the respiratory cycle during ictal phases and have increased expiratory adduction during interictal phases of seizures induced with standard i.v. convulsants in hyperoxic piglets.