PALB2 p.L24F突变在中国乳腺癌人群中的致病性和药物敏感性研究

PALB2是近年来发现的除BRCA1、BRCA2以外胚系突变频率最高的乳腺癌易感基因，与乳腺癌发生密切相关。我们前期通过对2279例中国乳腺癌人群进行PALB2基因的二代测序，共发现31个PALB2意义不明突变，而这些VUS正需要通过系统的功能验证鉴定其致病性，以明确其临床意义。本研究前期通过数据库生信预测筛选得到7个高风险致病的PALB2 VUS，通过点突变构建PALB2 VUS质粒载体，并应用I-SceI/U2OS/DR-GFP同源重组报告系统筛选鉴定得到高风险致病突变PALB2 p.L24F (c.72G>C)。本研究拟进一步验证高风险致病突变PALB2 p.L24F对DNA损伤修复功能的影响，阐明PALB2 p.L24F突变影响DNA损伤修复的内在机制。本研究亦通过细胞系及荷瘤小鼠模型筛选PALB2 p.L24F突变敏感的化疗药和DNA损伤靶向药，为临床诊疗提供新的思路。

Excluding BRCA1/2，PALB2 variants contribute most significantly to the germline mutation detection rate for breast cancer in recent years, and is closely related to the development of breast cancer. However, numerous variants found in the clinical tests are missense variants of uncertain significance (VUS). The lack of verification toward these VUS challenges their clinical application. In the previous stage, we performed the next-generation sequencing on PALB2 in 2,279 Chinese breast cancer patients and detected 31 PALB2 VUS. The pathogenicity and clinical significance of these PALB2 VUS are required to be identified by using systematic functional verification. A total of seven potentially pathogenic PALB2 VUS were identified by using in silico algorithms. We further tested the effects of these potentially pathogenic VUS on the homologous recombination (HR) activity of PALB2 by I-SceI/U2OS/DR-GFP reporting system and found a novel pathogenic PALB2 variant p.L24F (c.72G>C). In this study, we intend to verify the effects of PALB2 variant p.L24F on DNA damage repair. We also try to elucidate the intrinsic mechanisms of PALB2 variant p.L24F disrupting DNA damage repair. Furthermore, we intend to screen PALB2 p.L24F variant-sensitive chemotherapeutics and DNA damage targeting drugs by using in vitro cell lines and tumor-bearing mice models for better clinical outcomes.