Recurrent genetic variants and prioritization of variants of uncertain clinical significance associated with hereditary breast and ovarian cancer in families from the Region of Murcia.

Objectives: Hereditary breast and ovarian cancer (HBOC) follows an autosomal dominant inheritance pattern of cancer susceptibility genes. The risk of developing this disease is primarily associated with germline mutations in the BRCA1 and BRCA2 genes. The advent of massive genetic sequencing technologies has expanded the mutational spectrum of this hereditary syndrome, thereby increasing the number of variants of uncertain clinical significance (VUS) detected by genetic testing. Methods: A prevalence study of HBOC was performed within 2,928 families from the Region of Murcia, in southeastern Spain. Genetic testing enabled the identification of recurrent pathogenic variants and founder mutations, which were mainly related to the BRCA1 and BRCA2 genes. VUS testing was performed using a prioritization algorithm designed by our working group. Results: Variants c.68_69del, c.212+1G>A, and c.5123C>A were detected in 30 % of BRCA1 carriers, whereas exon 2 deletion concurrent with c.3264dupT, c.3455T>G and c.9117G>A variants were found in 30 % of BRCA2 carriers. A total of 16 VUS (15 %) were prioritized. Conclusions: The genotype-phenotype correlation observed in our study is consistent with the scientific literature. Furthermore, the founder effect of c.1918C>T (BRCA1) and c.8251_8254del (ATM) was verified in the Murcian population, whereas exon 2 deletion (BRCA2) was proven to be a Spanish founder mutation. Our algorithm enabled us to prioritize potentially pathogenic VUS that required further testing to determine their clinical significance and potential role in HBOC.

Next step in molecular genetics of hereditary breast/ovarian cancer: Multigene panel testing in clinical actionably genes and prioritization algorithms in the study of variants of uncertain significance.

INTRODUCTION: BRCA1 and BRCA2 are the two main genes causing hereditary breast and ovarian cancer (HBOC). However, thanks to the development of Next Generation Sequencing (NGS), other genes linked to this syndrome (CHEK2, BRIP1, ATM and PALB2 among others) can be analysed. MATERIAL AND METHODS: an analysis by multigene panel testing was performed in 138 index cases (ICs) from HBOC Spanish families with a previous non-informative result for BRCA1/2. The BRCA Hereditary Cancer Master™ Plus kit, including 26 actionable and candidate genes related to HBOC was employed. Once classified, an algorithm was employed to prioritized those variants of unknown significance with a higher risk of having a deleterious effect. Moreover, a mRNA splicing assay was performed for the prioritized VUS c.3402+3A > C in ATM, located at intron 23. RESULTS: A total of 82 variants were found: 70 VUS and 12 pathogenic or probably pathogenic variants. The diagnostic yield in actionable genes non-BRCA was 7.97% of the total tested ICs. Overall, 19 VUS were prioritized, which meant 27% of the 70 total VUS. RNA analysis of the variant 3402+3A > C confirmed a deleterious impact on splicing. DISCUSSION: The implementation of a multigene panel in HBOC studied families improved the diagnostic yield, concordant with results obtained in previous publications. Due to the important number of VUS obtained in NGS, the application of a prioritization algorithm is needed in order to select those variants in which it is necessary to conduct further studies.

Second trimester angiotensing-converting enzyme and uterine artery Doppler as predictors of preeclampsia in a high-risk population.

OBJECTIVE: To investigate whether serum angiotensing-converting enzyme (ACE) and uterine artery Doppler (UAD) are useful markers as predictors of preeclampsia (PE) in a high-risk population. METHODS: Patients at risk of PE (n = 68) were subclassified as having PE (n = 8) or no PE (n = 60). Blood samples were obtained between 19 and 22 weeks of gestation. Doppler ultrasound of the uterine arteries was done at the time of blood sampling. Maternal serum ACE was determined through spectrophotometry assay (A15 Biosystem, ATOM, Barcelona, Spain). RESULTS: Comparing the group who presented PE with the one who was not developed it, we found significant differences for ACE (54.2 ± 21.2, 38.1 ± 12.3 U/L; p = 0.003); the pulsatility index (PI) (1.2 ± 0, 3.1 ± 0.3; p = 0.032) and resistance index (RI) (0.7 ± 0.1, 0.5 ± 0.1; p = 0.004). The AUC for ACE was 0.724, so we selected the cutoff of 36.5 U/L (sensitivity: 62.5% and specificity: 86.7%). The AUC for PI was 0.652 choosing a cutoff of 1.4 (sensitivity: 57.1% and specificity: 93.1%). The AUC for RI was 0.712 and the cutoff of 0.7 (sensitivity of 71.4% and specificity: 89.6%). The combination that allowed us to increase the diagnostic performance was the ACE+RI with Doppler study, increasing the AUC to 0.872. CONCLUSIONS: ACE, PI and RI as parameters of Doppler study were useful predictors of PE in the second trimester of gestation. The best combination to increase the diagnostic performance was ACE with the RI.

Placental growth factor, soluble fms-like tyrosine kinase 1 and progesterone as diagnostic biomarkers for ectopic pregnancy and missed abortion.

OBJECTIVE: The aim of this study is to investigate if progesterone, placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt1) serum levels are useful markers to differentiate between ectopic pregnancy (EP), missed abortion (MA) and viable intrauterine implantation pregnancy (IUP). METHODS: We designed a retrospective case-control study which included 100 pregnant women (50 EP and 50 MA) at 6-8 weeks of gestation with ßhCG serum levels between 800 and 3500 UI/L and a viable IUP group. Progesterone, PlGF and sFlt-1 levels were measured with an electrochemiluminescence assay (Roche Diagnostics, Manheim, Alemania). A non parametric test was used to compare the markers in the different groups and we used receiver operating characteristic (ROC) curve analysis to calculate the area under the curve (AUC). RESULTS: When we compared the EP group with the MA group, we didn't find significant differences for PlGF (15.1[13.2-17.4]/16.7[12.8-18.7] pg/mL) (p=0.275). We only obtained significant differences for progesterone (9.1[3.1-16.8]/2.6[1.3-6.1] ng/mL) (p<0.001) and sFlt-1 (84[65-96]/126[94-256] pg/mL) (p<0.001). The AUC for progesterone was 0.756 and the cutoff point with better sensitivity and lower false positive rate was 6 ng/mL (sensitivity=60%, specificity=72.7%). The AUC for sFlt-1 was 0.842 and the cutoff point was 93 pg/mL (sensitivity=84.5%, specificity=86.3%). The combination of both markers allowed us to increase the AUC to 0.910. CONCLUSIONS: In conclusion, the present study suggests that sFlt-1 could be a useful marker to differentiate between an EP or a MA when ßhCG levels are similar in both groups. The combination of sFlt-1 with progesterone helps to increase the diagnostic performance.

Novel BRCA1 deleterious mutation (c.1918C>T) in familial breast and ovarian cancer syndrome who share a common ancestry.

Mutations in breast cancer susceptibility (BRCA) genes lead to defects in DNA repair processes resulting in elevated genome instability and predisposing to breast and ovarian cancer. We report a novel mutation (c.1918C>T) in the exon 11 of the BRCA1 gene that consists of a nonsense mutation that causes a stop codon downstream in the 640 position of the protein. The mutation was present in two Spanish unrelated families and was associated with four breast cancer cases, including two bilateral breast cancer (one of them synchronous). The median age/mean age (range) was 48.5/44.25 years (27-53). This finding led us to perform haplotype analysis in all family carriers. Four highly polymorphic microsatellite markers were used (17-3858, 17-3930, D17S855, D17S1326) to establish whether or not all these families had a common ancestor. This analysis showed that all mutation carriers of these families had a common haplotype. None of the noncarriers of the mutation or of the 24 healthy controls showed this haplotype. Therefore, the c.1918C>T mutation carriers from these two families allows us to assert that all analyzed mutation carriers share a common ancestry.