Population-based germline breast cancer gene association studies and meta-analysis to inform wider mainstream testing
Menée à partir des données de trois études incluant au total 101 397 femmes atteintes d'un cancer du sein et 312 944 témoins, cette méta-analyse évalue la fréquence de variants pathogènes au niveau de 37 gènes de susceptibilité puis examine leur association avec le risque de cancer du sein pour identifier les gènes devant être ciblés par les tests de génomique constitutionnelle
Background : Germline genetic testing, previously restricted to familial and young-onset breast cancer, is now offered increasingly broadly to ‘population-type’ breast cancer patients in mainstream oncology clinics, with wide variation in the genes included.
Methods : Weighted meta-analysis was performed for three population-based case-control studies (BRIDGES, CARRIERS and UK Biobank) comprising in total 101,397 women with breast cancer and 312,944 women without breast cancer, to quantify for 37 putative breast cancer susceptibility genes (BCSGs) the frequency of pathogenic variants (PVs) in unselected, ‘population-type’ breast cancer cases and their association with breast cancer and its subtypes.
Results : Meta-analysed odds ratios (ORs) and frequencies of PVs in population-type breast cancer cases were generated for BRCA1 (OR= 8.73 (95% CI 7.47-10.20), 1 in 101), BRCA2 (OR=5.68 (5.13-6.30), 1 in 68) and PALB2 (OR= 4.30 (95% CI 3.68-5.03), 1 in 187). For both CHEK2 (OR=2.40 (95% CI 2.21-2.62), 1 in 73) and ATM (OR=2.16 (95%CI 1.93-2.41), 1 in 132) subgroup analysis showed stronger association with ER-positive disease. Magnitude of association and frequency of PVs were low for RAD51C (OR=1.53 (95%CI 1.15-2.04), 1 in 913), RAD51D (OR=1.76, (95%CI 1.15-2.41, 1 in 1079) and BARD1 (OR=2.34 (1.85-2.97), 1 in 672); frequencies and associations were moderately higher restricting to triple-negative breast cancers.
The PV-frequency in ‘population-type’ breast cancer cases was very low for ‘syndromic’ BCSGs TP53 (1 in 1844), STK11 (1 in 11,525), CDH1 (1 in 2668), PTEN (1 in 3755) and NF1 (1 in 1470), with metrics of association also modest ranging from OR=3.62 (95%CI 1.98-6.61) for TP53 down to OR=1.60 (95%CI 0.48-5.30) for STK11.
Conclusions : These metrics reflecting ‘population-type’ breast cancer will be informative to defining the appropriate gene set as we continue to expand to germline testing out to more unselected population-type breast cancer cases.
Annals of Oncology , article en libre accès, 2023