These include carboxylesterase 2 expression (neoadjuvant FOLFIRINOX), Hu-antigen R, microRNAs miR-142-5p and miR-204, human equilibrative nucleoside transporters and human concentrative nucleoside transporter-3 (gemcitabine), BRCA gene mutations (platinum-based chemotherapy and poly [Adenosine diphosphate ribose] polymerase inhibitors), and high microsatellite instability or mismatch repair deficiency (pembrolizumab) [44–52]. The gene discussed is CES2; the disease is hyperinsulinemic hypoglycemia, familial, 4.