Pre-existing immunity drives the response to neoadjuvant chemotherapy in esophageal adenocarcinoma

Esophageal adenocarcinoma (EAC) is a highly aggressive tumor. Patients with locally advanced disease undergo neoadjuvant chemotherapy (nCT) before surgery, however fewer than 30% of treated patients achieve a pathological complete response associated with increased 5-year overall survival. We set out to elucidate the mechanisms the response to nCT by multi-dimensional profiling of pre-treatment tumor biopsies and blood samples from EAC patients. In particular we performed whole exome sequencing (WES) and RNAseq on n=26 baseline EAC tumor; two additional EAC samples underwent only WES. WES on matched peripheral blood mononuclear cells (PBMCs) were used as germline control.

Type: Other
Archiver: European Genome-Phenome Archive (EGA)

1 Dataset 1 Publication

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Dataset ID	Description	Technology	Samples
EGAD00001010876	Exome sequencing was performed on n=28 treatment-naïve esophageal adenocarcinoma (EACs). Three to four biopsies sampling different areas of each tumor were pooled before nucleic acid extractions to mitigate the elevated heterogeneity described for EAC. WES was performed on EAC biopsies at 120X average coverage, with autologous PBMCs used as germline controls at 80X average coverage. Libraries were prepared from 30 ng of input DNA using the SureSelect QXT Human All Exon V7 kit (Agilent Technologies) and sequenced on the NextSeq 550 (Illumina), 2x150 bp. BCL files were demultiplexed to FastQ files using bcl2fastq2 software (Illumina). Three paired end sequencing batches were analyzed independently (Batch1: samples 8, 10, 11, 12, 15, 17, 18; Batch2: samples 20, 24, 25, 26, 27, 29, 30, 31, 33, 34 ; Batch3: samples 35, 37, 39, 40, 41, 43, 45, 48, 54, 55, 57). RNA sequencing was performed on n=26 treatment-naïve esophageal adenocarcinoma (EACs). Three to four biopsies sampling different areas of each tumor were pooled before nucleic acid extractions to mitigate the elevated heterogeneity described for EAC. RNAseq libraries were prepared on 50 ng of total RNA (with RNA integrity index RIN >=7) with the TruSeq Stranded mRNA library preparation kit (Illumina) in accordance with low-throughput protocol. After PCR enrichment (15 cycles) and purification of adapter-ligated fragments, the concentration and length of DNA fragments were measured using D1000 Screen Tape System (Agilent), obtaining a median insert size of 311 nucleotides. Then, RNAseq libraries were sequenced using the Illumina NovaSeq platform, 1x100 bp, obtaining on average 100 million single reads per sample.	Illumina NovaSeq 6000 NextSeq 550	166

Publications	Citations
Preexisting Immunity Drives the Response to Neoadjuvant Chemotherapy in Esophageal Adenocarcinoma. Arbore G, Albarello L, Bucci G, Punta M, Cossu A, Fanti L, Maurizio A, Di Mauro F, Bilello V, Arrigoni G, Bonfiglio S, Biancolini D, Puccetti F, Elmore U, Vago L, Cascinu S, Tonon G, Rosati R, Casorati G, Dellabona P. Cancer Res 83: 2023 2873-2888	5