115P Next-generation sequencing and liquid biopsy: Overcoming tissue limitations in oncology

Subsequently, patients consented at Newcastle Hospitals were identified on the TARGET National database.Results: We recruited 612 patients; out of them, 35/612 (5.7%) tumours harboured RB1 and TP53 gene co-alteration.Of these, 15 (42.8%) were lung cancers, 5 (14.3%) prostate cancers, 5 (14.3%) breast cancers, 4 (11.4%)bladder cancers, 2 (5.7%) colon cancer, 2 (5.7%) oesophagus carcinomas, 1 (2.9%) liver and 1 (2.9%) adrenocortical carcinoma.The majority of TP53 mutation were point mutations (62.9%).Differenly, for RB1 14 (40%) were frameshift mutations, 12 (34.3%)mutations leading to stop codons, 5 (14.3%) splice site mutations, 3 (8.6%)point mutations, and 1 (2.9%) an intron rearrangement.At the time of original diagnosis, 12/35 (34.3%) patients had histological evidence of NEC, while the remaining 23 (65.7%) started as histologically confirmed adenocarcinomas.The time from diagnosis to testing for TARGET was 27.0 mos for tNECs and 15.8 mos for primary NECs, while overall survival from TARGET was 5.6 and 7.2 mos, respectively.Conclusions: Our research shows that ctDNA analyses can reliably detect RB1 and TP53 co-mutation in a wide range of cancers without the constraints of a tissue biopsy, identifying both NECs and tNECs.Interestingly, while cancers originally identified as adenocarcinomas have a better outcome compared to NEC, their OS is comparable upon NE transformation.