Genetic Profiling Of Goblet Cell Carcinoid Of The Appendix Compared To Appendiceal Adenocarcinoma
*Trang Nguyen1, *Mary Garland-Kledzik2, *Paul Helft1, Eugene Ceppa1, Nicholas Zyromski1, C. Max Schmidt1, Attila Nakeeb1, Michael House1
1Indiana University School of Medicine, Indianapolis, IN;2John Wayne Cancer Institute, Santa Monica, CA
OBJECTIVE(S): Goblet cell carcinoid of the appendix (GCC-A) is a rare cancer with a mixed neuroendocrine and epithelial histology. Given the lack of robust clinical data, GCC-A is often treated along the same surgical and systemic therapy guidelines as appendiceal adenocarcinoma. The aim of this study is to compare the genetic profile of GCC-A versus appendiceal adenocarcinoma and mucinous adenocarcinoma using the AACR Project Genomics Evidence Neoplasia Information Exchange (GENIE) Database, one of the largest public cancer genomic data sets.
METHODS: Data from 152 appendiceal adenocarcinoma (A-A) patients, 134 mucinous appendiceal adenocarcinoma (MA-A) patients, and 30 GCC-A patients were analyzed from AACR Genie v 6.1. Genes mutated in less than two patients were excluded from analysis. Potentially actionable mutations were defined by the OncoKB annotations as having at least investigational evidence of a therapeutic drug.
RESULTS: Appendiceal adenocarcinoma and mucinous appendiceal adenocarcinoma had higher mutation rates compared to GCC-A for KRAS (3.33% GCC-A, 47.4% A-A, 70.9% MA-A), GNAS (0% GCC-A, 17.2% A-A, 44.0% MA-A), and TP53 (3.3% GCC-A, 33.1% A-A, 25.4% MA-A). GCC-A tumors had a higher rate of ARID1A mutations (11.1% GCC-A, 5.3% A-A, 6.6% MA-A), SOX9 mutations (18.5% GCC-A, 10.8% A-A, 4.1% MA-A) and SMAD4 mutations (23.3% GCC-A, 15.2% A-A, 9.7% MA-A). Another commonly mutated gene was APC (10.0% GCC-A, 13.8% A-A, 7.5% MA-A). Four patients (13.3%) with GCC-A had potentially actionable mutations or copy number alterations (ERBB2, NRAS, FGFR1 Amplification) while 26 (16.8%) of A-A patients and 16 (11.6%) of MA-A patients had potentially actionable mutations or copy number alterations.
CONCLUSIONS: The genetic landscape of goblet cell carcinoid of the appendix is distinct from appendiceal adenocarcinoma and mucinous appendiceal adenocarcinoma. Though traditionally these appendiceal neoplasms have been treated with similar chemotherapeutic agents, obtaining molecular profiles of these appendiceal cancers can help identify potentially actionable mutations and personalize treatment options for patients with these rare tumors.
Back to 2020 Abstracts