123P Correlation between MSI, TMB and BLM gene mutation in solid tumors

BackgroundBLM (BLM RecQ Like Helicase) is a DNA helicase that plays an important role in maintaining genomic integrity. Researches have shown dysfunction of BLM was associated with PD-L1 expression. This study aimed to reveal the relation between BLM-mutant and BLM-wild type tumors tumor mutation burden (TMB) microsatellite instability (MSI).MethodsWe retrospectively analyzed mutations 15189 Chinese patients pan-cancer during 2019-2021(Simcere Diagnosis, Nanjing, China). Next-generation sequencing (NGS) assessed somatic tissue. We figured out frequency, TMB MSI BLM-mutant, wild-type.ResultsBLM mutants were detected 267 (1.8%) samples. The top 5 frequent cancers lung cancer (66, 24.7%), colorectal (64, 24.0%), liver (31, 11.0%), gastric (20, 7.5%) endometrial (12, 4.2%). variants included missense/indel/insert (80.2%),truncation (10.5%), CNV (7.1%) splicing site variant (1.9%), fusion (0.3%). inactive are either frameshift or mutations, recurring few hot spots (N515Mfs*16/fs/Kfs*2, D757Tfs*4). And we found group significantly higher than wild-type group[TMB-H (TMB ≥10 musts/Mb): BLM-MUT vs BLM-WT, 52.1% 9.1%, p < 0.01; MSI-H: 27.0% vs1.0% 0.01]. then, separately correlation MSI, gene cancers. Over 80% high values[colorectal (BLM-MUT 87.5% 8.4%, p<0.001); 81.8% 17.4%, p<0.01)].ConclusionsWe solid tumor. Our data showed tumors. Especially cancer, over values. In short, our molecular marker immunotherapy.Legal entity responsible for studyThe authors.FundingHas not received any funding.DisclosureAll authors declared no conflicts interest. (MSI). MethodsWe wild-type. ResultsBLM p<0.01)]. ConclusionsWe immunotherapy.