George J Burghel

Effects of higher-than-expected control population allele frequency on classification of loss-of-function variants in cancer susceptibility genes

A query was sent to the cancer predisposition gene variant database Cancer Variant Interpretation Group UK, on the nonsense variant in NM_032043.3(BRIP1):c.2392C>T,p.(Arg798Ter). The submitter classified this as a variant of uncertain significance, providing very strong variant effect evidence with the intention of adding supporting pedigree information, according to the guidelines used for classification. However, the relatively high population frequency in the UKB cohort of 367/439 920 (0.083%) was a concern as it is higher than expected for the disease frequency, which would reduce the predicted pathogenicity score. This situation highlights the increasing concerns over the use of population data in pathogenicity classification of truncating/loss-of-function (LoF) variants in known cancer predisposition genes, particularly since the addition of UKB control data. Here, we have conducted a series of case-control comparisons for common truncating variants in known breast/ovarian cancer-associated genes, as well as LZTR1-related schwannomatosis, to address this issue using our Manchester cancer screening population compared with controls in UKB data. Our data show strong ORs for these common truncating variants. We propose that for truncating variants in cancer susceptibility genes with a significant case-control OR, apparently conflicting population frequency evidence criteria should be avoided.

The NHS England Jewish BRCA Testing Programme: overview after first year of implementation (2023–2024)

Background The NHS Jewish BRCA Testing Programme is offering germline BRCA1 and BRCA2 genetic testing to people with ≥1 Jewish grandparent. Who have an increased likelihood of having an Ashkenazi Jewish (AJ) founder germline pathogenic variant (gPV) compared with the general population. Testing is offered via a self-referral, home-based saliva sampling pathway, supported by a genetic counsellor telephone helpline. A first-of-its-kind in the United Kingdom (UK) for population genetic testing, outside of research. Methods We reviewed data from germline testing of 5389 people who registered during the soft-launch phase (January 2023–January 2024) and their families to observe trends in uptake and outcomes of testing. Results Of the 5389 self-referrals, 4339 (80.5%) consented to testing. Of those with results returned, 2.3% (98/4,274) had a gPV (89.8% AJ founder and 10.2% non-AJ founder). Notably, the detection rate was higher in men (42/790, 5.3%) compared with women (56/3484, 1.6%), with the proportion reporting known BRCA variants within the family prior to consent also significantly increased (13.1% compared with 9.2%, respectively). Conclusion Overall detection rates of gPVs are similar to those reported elsewhere from Jewish population testing. The pathway, particularly for males, may attract uptake of testing by those previously aware of familial gPVs.

Pathogenic variant detection rate varies considerably in male breast cancer families and sporadic cases: minimal additional contribution beyond BRCA2, BRCA1 and CHEK2

Background Male breast cancer (MBC) affects around 1 in 1000 men and is known to have a higher underlying component of high and moderate risk gene pathogenic variants (PVs) than female breast cancer, particularly in BRCA2. However, most studies only report overall detection rates without assessing detailed family history. Methods We reviewed germline testing in 204 families including at least one MBC for BRCA1, BRCA2, CHEK2 c.1100DelC and an extended panel in 93 of these families. Individuals had MBC (n=118), female breast cancer (FBC)(n=80), ovarian cancer (n=3) or prostate cancer-(n=3). Prior probability of having a BRCA1/2 PV was assessed using the Manchester Scoring System (MSS). Results In the 204 families, BRCA2 was the major contributor, with 51 (25%) having PVs, followed by BRCA1 and CHEK2, with five each (2.45%) but no additional PVs identified, including in families with high genetic likelihood on MSS. Detection rates were 85.7% (12/14) in MSS ≥40 and 65.5% with MSS 30–39 but only 12.8% (6/47) for sporadic breast cancer. PV rates were low and divided equally between BRCA1/2 and CHEK2. Conclusion As expected, BRCA2 PVs predominate in MBC families with rates 10-fold those in CHEK2 and BRCA1. The MSS is an effective tool in assessing the likelihood of BRCA1/2 PVs.

Multi-Maintenance Olaparib Therapy in Relapsed, Germline BRCA1/2 -Mutant High-Grade Serous Ovarian Cancer (MOLTO): A Phase II Trial

Abstract Purpose: A single maintenance course of a PARP inhibitor (PARPi) improves progression-free survival (PFS) in germline BRCA1/2-mutant high-grade serous ovarian cancer (gBRCAm-HGSOC). The feasibility of a second maintenance course of PARPi was unknown. Patients and Methods: Phase II trial with two entry points (EP1, EP2). Patients were recruited prior to rechallenge platinum. Patients with relapsed, gBRCAm-HGSOC were enrolled at EP1 if they were PARPi-naïve. Patients enrolled at EP2 had received their first course of olaparib prior to trial entry. EP1 patients were retreated with olaparib after RECIST complete/partial response (CR/PR) to platinum. EP2 patients were retreated with olaparib ± cediranib after RECIST CR/PR/stable disease to platinum and according to the platinum-free interval. Co-primary outcomes were the proportion of patients who received a second course of olaparib and the proportion who received olaparib retreatment for ≥6 months. Functional homologous recombination deficiency (HRD), somatic copy-number alteration (SCNA), and BRCAm reversions were investigated in tumor and liquid biopsies. Results: Twenty-seven patients were treated (EP1 = 17, EP2 = 10), and 19 were evaluable. Twelve patients (63%) received a second course of olaparib and 4 received olaparib retreatment for ≥6 months. Common grade ≥2 adverse events during olaparib retreatment were anemia, nausea, and fatigue. No cases of MDS/AML occurred. Mean duration of olaparib treatment and retreatment differed (12.1 months vs. 4.4 months; P < 0.001). Functional HRD and SCNA did not predict PFS. A BRCA2 reversion mutation was detected in a post-olaparib liquid biopsy. Conclusions: A second course of olaparib can be safely administered to women with gBRCAm-HGSOC but is only modestly efficacious. See related commentary by Gonzalez-Ochoa and Oza, p. 2563

Germline BRCA1/2 status and chemotherapy response score in high-grade serous ovarian cancer

Abstract Background High-grade serous ovarian cancer (HGSOC) can be treated with platinum-based neoadjuvant chemotherapy (NACT) and delayed primary surgery (DPS). Histopathological response to NACT can be assessed using Böhm’s chemotherapy response score (CRS). We investigated whether germline BRCA1/2 (gBRCA1/2) genotype associated with omental CRS phenotype. Methods A retrospective study of patients with newly diagnosed FIGO stage IIIC/IV HGSOC prescribed NACT and tested for gBRCA1/2 pathogenic variants (PVs) between September 2017 and December 2022 at The Christie Hospital. The Cox proportional hazards model evaluated the association between survival and key clinical factors. The chi-square test assessed the association between CRS3 (no/minimal residual tumour) and gBRCA1/2 status. Results Of 586 eligible patients, 393 underwent DPS and had a CRS reported. Independent prognostic factors by multivariable analysis were gBRCA1/2 status (PV versus wild type [WT]), CRS (3 versus 1 + 2), surgical outcome (complete versus optimal/suboptimal) and first-line poly (ADP-ribose) polymerase-1/2 inhibitor maintenance therapy (yes versus no) (all P < 0.05). There was a non-significant trend for tumours with a gBRCA2 PV having CRS3 versus WT (odds ratio [OR] = 2.13, 95% confidence intervals [CI] 0.95–4.91; P = 0.0647). By contrast, tumours with a gBRCA1 PV were significantly less likely to have CRS3 than WT (OR = 0.35, 95%CI 0.14–0.91; P = 0.0291). Conclusions Germline BRCA1/2 genotype was not clearly associated with superior omental CRS. Further research is required to understand how HGSOC biology defines CRS.

Extended panel testing in ovarian cancer reveals BRIP1 as the third most important predisposition gene

The prevalence of germline pathogenic variants (PVs) in homologous recombination repair (HRR) and Lynch syndrome (LS) genes in ovarian cancer (OC) is uncertain. An observational study reporting the detection rate of germline PVs in HRR and LS genes in all OC cases tested in the North West Genomic Laboratory Hub between September 1996 and May 2024. Effect sizes are reported using odds ratios (ORs) and 95% confidence intervals (95% CI) for unselected cases tested between April 2021 and May 2024 versus 50,703 controls from the Breast Cancer Risk after Diagnostic Gene Sequencing study. 2934 women were tested for BRCA1/2 and 433 (14.8%) had a PV. In up to 1572 women tested for PVs in non-BRCA1/2 HRR genes, detection rates were PALB2 = 0.8%, BRIP1 = 1.1%, RAD51C = 0.4% and RAD51D = 0.4%. In 940 unselected cases, BRIP1 (OR = 8.7, 95% CI 4.6-15.8) was the third most common OC predisposition gene followed by RAD51C (OR = 8.3, 95% CI 3.1-23.1), RAD51D (OR = 6.5, 95% CI 2.1-19.7), and PALB2 (OR = 3.9, 95% CI 1.5-10.3). No PVs in LS genes were detected in unselected cases. Panel testing in OC resulted in a detection rate of 2% to 3% for germline PVs in non-BRCA1/2 HRR genes, with the largest contributor being BRIP1. Screening for LS in unselected cases of OC is unnecessary.

EMQN best practice guidelines for genetic testing in hereditary breast and ovarian cancer

AbstractHereditary Breast and Ovarian Cancer (HBOC) is a genetic condition associated with increased risk of cancers. The past decade has brought about significant changes to hereditary breast and ovarian cancer (HBOC) diagnostic testing with new treatments, testing methods and strategies, and evolving information on genetic associations. These best practice guidelines have been produced to assist clinical laboratories in effectively addressing the complexities of HBOC testing, while taking into account advancements since the last guidelines were published in 2007. These guidelines summarise cancer risk data from recent studies for the most commonly tested high and moderate risk HBOC genes for laboratories to refer to as a guide. Furthermore, recommendations are provided for somatic and germline testing services with regards to clinical referral, laboratory analyses, variant interpretation, and reporting. The guidelines present recommendations where ‘must’ is assigned to advocate that the recommendation is essential; and ‘should’ is assigned to advocate that the recommendation is highly advised but may not be universally applicable. Recommendations are presented in the form of shaded italicised statements throughout the document, and in the form of a table in supplementary materials (Table S4). Finally, for the purposes of encouraging standardisation and aiding implementation of recommendations, example report wording covering the essential points to be included is provided for the most common HBOC referral and reporting scenarios. These guidelines are aimed primarily at genomic scientists working in diagnostic testing laboratories.