Genomic profiling of gallbladder carcinoma: Targetable mutations and pathways involved

Abstract

Gallbladder cancer (GBC) carries a poor prognosis and frequently present in late stages of disease. Identification of targetable molecular changes for selecting appropriate treatment and identifying prognostic and therapeutic subsets is required. Next-generation sequencing (NGS) using a frequently mutated for GBC may provide a reference for clinical management. The primary aim of the current study was to analyze the frequency of individual genetic alterations in GBC and to correlate with clinicopathological characteristics. A retrospective study was conducted using 22 gene panel examined NGS based approach for the detection of actionable genomic mutations in 37 GBC patients. The genetic and clinicopathological characteristics were analyzed. The number of mutations in cases was ranged from 1 to 15. A total of 171 mutations were identified in FFPE tissue DNA. The most common alterations were TP53 (90.90%), SMAD4 (60.60%), NOTCH1(45.45)& ERBB2 (45.45%), PIK3CA (33.33%) and MET (30.30)& PTEN (30.30%). Among the 22 gene panel, the TP53 gene was associated with histopathological differentiation (p = 0.0001), ERBB4 & ALK mutation was associated with necrosis (p = 0.012, 0.027), EGFR mutation was associated with mucin status (p = 0.023) and ERBB2 gene mutation was associated with T stage (p = 0.036). The study provides an overview of the genetic alterations in GBC patients.Targetable mutations are present in 89.91% cases of GBC which include SMAD4, NOTCH1, ERBB2&4, PIK3CA, MET, PTEN, EGFR, KRAS and BRAF. Metastatic disease was associated with high frequency of CTNNB1, KRAS and NRAS gene mutations.

Keywords: Gallbladder carcinoma; Genomic profiling; Next generation sequencing; Single nucleotide variation.