p53/ Status Assessment in Gastroesophageal Adenocarcinoma.

Chromosomal instability (CIN) is very frequent in gastroesophageal adenocarcinoma (GEA) and it is characterized by deletions/mutations resulting in p53 nuclear accumulation, as revealed by immunohistochemistry (IHC), which considers the cases with "high" staining levels to be positive. Aiming to improve aberrant detection, droplet digital PCR (ddPCR) was used to evaluate deletion in formalin-fixed, paraffin-embedded DNA (FFPE-DNA) and cell-free DNA (cfDNA). To further investigate the mutational profile, next-generation sequencing (NGS) was performed in a subset of FFPE samples.