Mainstreaming germline BRCA1/2 testing in non-mucinous epithelial ovarian cancer in the North West of England.

Poly(ADP-ribose) polymerase (PARP) inhibitors improve survival in BRCA-mutant high-grade serous ovarian carcinoma. As a result, germline and somatic BRCA1/2 testing has become standard practice in women diagnosed with ovarian cancer. We outline changes in testing and detection rates of germline BRCA1/2 pathogenic variants (PVs) in cases of non-mucinous epithelial ovarian cancer diagnosed during three eras, spanning 12 years, within the North West of England, and compare the uptake of cascade testing in families identified by oncology-led mainstreaming versus regional genetics clinics. Eras included: Period 1 (20% risk threshold for testing): between January 2007 and May 2013; Period 2 (10% risk threshold for testing): between June 2013 and October 2017 and; Period 3 (mainstream testing): between November 2017 and November 2019. A total of 1081 women underwent germline BRCA1/2 testing between January 2007 and November 2019 and 222 (20.5%) were found to have a PV. The monthly testing rate increased by 3.3-fold and 2.5-fold between Periods 1-2 and Periods 2-3, respectively. A similar incidence of germline BRCA1/2 PVs were detected in Period 2 (17.2%) and Period 3 (18.5%). Uptake of cascade testing from first-degree relatives was significantly lower in those women undergoing mainstream testing compared with those tested in regional genetics clinics (31.6% versus 47.3%, P = 0.038). Mainstream testing allows timely detection of germline BRCA1/2 status to select patients for PARP inhibitors, but shortfalls in the uptake of cascade testing in first-degree relatives requires optimisation to broaden benefits within families.

A Dominantly Inherited 5' UTR Variant Causing Methylation-Associated Silencing of BRCA1 as a Cause of Breast and Ovarian Cancer.

Pathogenic variants in BRCA1 or BRCA2 are identified in ∼20% of families with multiple individuals affected by early-onset breast and/or ovarian cancer. Extensive searches for additional highly penetrant genes or alternative mutational mechanisms altering BRCA1 or BRCA2 have not explained the missing heritability. Here, we report a dominantly inherited 5' UTR variant associated with epigenetic BRCA1 silencing due to promoter hypermethylation in two families affected by breast and ovarian cancer. BRCA1 promoter methylation of ten CpG dinucleotides in families who are affected by breast and/or ovarian cancer but do not have germline BRCA1 or BRCA2 pathogenic variants was assessed by pyrosequencing and clonal bisulfite sequencing. RNA and DNA sequencing of BRCA1 from lymphocytes was undertaken to establish allelic expression and the presence of germline variants. BRCA1 promoter hypermethylation was identified in 2 of 49 families in which multiple women are affected by grade 3 breast cancer or high-grade serous ovarian cancer. Soma-wide BRCA1 promoter hypermethylation was confirmed in blood, buccal mucosa, and hair follicles. Pyrosequencing showed that DNA was ∼50% methylated, consistent with the silencing of one allele, which was confirmed by clonal bisulfite sequencing. RNA sequencing revealed the allelic loss of BRCA1 expression in both families and that this loss of expression segregated with the heterozygous variant c.-107A>T in the BRCA1 5' UTR. Our results establish a mechanism whereby familial breast and ovarian cancer is caused by an in cis 5' UTR variant associated with epigenetic silencing of the BRCA1 promoter in two independent families. We propose that methylation analyses be undertaken to establish the frequency of this mechanism in families affected by early-onset breast and/or ovarian cancer without a BRCA1 or BRCA2 pathogenic variant.

Screening for familial ovarian cancer: failure of current protocols to detect ovarian cancer at an early stage according to the international Federation of gynecology and obstetrics system.

PURPOSE: To assess the effectiveness of annual ovarian cancer screening (transvaginal ultrasound and serum CA-125 estimation) in detecting presymptomatic ovarian cancer in women at increased genetic risk. PATIENTS AND METHODS: A cohort of 1,110 women at increased risk of ovarian cancer were screened between January 1991 and March 2004; 553 were moderate-risk individuals (4% to 10% lifetime risk) and 557 were high-risk individuals (> 10% lifetime risk). Outcome measurements include the number and stage of screen-detected cancers, the number and stage of cancers not detected at screening, the number of equivocal screening results requiring recall/repetition, and the number of women undergoing surgery for benign disease. RESULTS: Thirteen epithelial ovarian malignancies (12 invasive and one borderline), developed in the cohort. Ten tumors were detected at screening: three International Federation of Gynecology and Obstetrics (FIGO) stage I (including borderline), two stage II, four stage III, and one stage IV. Of the three cancers not detected by screening, two were stage III and one was stage IV; 29 women underwent diagnostic surgery but were found not to have ovarian cancer. CONCLUSION: Annual surveillance by transvaginal ultrasound scanning and serum CA-125 measurement in women at increased familial risk of ovarian cancer is ineffective in detecting tumors at a sufficiently early stage to influence prognosis. With a positive predictive value of 17% and a sensitivity of less than 50%, the performance of ultrasound does not satisfy the WHO screening standards. In addition, the combined protocol has a particularly high false-positive rate in premenopausal women, leading to unnecessary surgical intervention.