Cells reconstituted with WT-PALB2 showed substantially less sensitivity to olaparib than cells expressing p.A1025R and p.I944N (Fig. 4a). Similar results were observed for cisplatin treatment, although the difference in sensitivity was less pronounced (Fig. 4b). p.L24S, p.L1070P, and p.L35P were also associated with greater sensitivity to olaparib (Fig. 4c) and cisplatin (Fig. 4d) than WT-PALB2.

Cells reconstituted with WT-PALB2 showed substantially less sensitivity to olaparib than cells expressing p.A1025R and p.I944N (Fig. 4a). Similar results were observed for cisplatin treatment, although the difference in sensitivity was less pronounced (Fig. 4b). p.L24S, p.L1070P, and p.L35P were also associated with greater sensitivity to olaparib (Fig. 4c) and cisplatin (Fig. 4d) than WT-PALB2.

WT-PALB2 was associated with robust formation of damage-induced RAD51 foci, whereas the four variants were associated with defective foci formation (Fig. 3d, e).

Results for individual PALB2 variants were normalized relative to WT-PALB2 and the p.Tyr551ter (p.Y551X) truncating variant on a 1:5 scale with the fold change in GFP-positive cells for WT set at 5.0 and fold change GFP-positive cells for p.Y551X set at 1.0. The p.L24S (c.71T>C), p.L35P (c.104T>C), p.I944N (c.2831T>A), and p.L1070P (c.3209T>C) variants and all protein-truncating frame-shift and deletion variants tested were deficient in HDR activity, with normalized fold change <2.0 (approximately 40% activity) (Fig. 1a).

A total of 84 PALB2 patient-derived missense variants reported in ClinVar, COSMIC, and the PALB2 LOVD database were selected

Source Data

Source Data

We, therefore, analyzed the effect of 48 PALB2 VUS (Fig. 2a, blue) and one synthetic missense variant (p.A1025R) (Fig. 2a, purple)29 on PALB2 function in HR.