Gastric cancer (GC) is one of the most common malignant tumors of the digestive system, and its prognosis remains poor because most tumors were detected in late stages and the 5-year survival is less than 5%. The Cancer Genome Atlas (TCGA) study found that 70% of all GCs have mutations that can be targeted with existing drugs, yet only four molecularly-guided therapies have been approved. GCs have strong disparities in incidence, mortality and survival that disproportionately affect different populations of color. No large-scale cancer genomic research has been carried out in U.S. minority populations. GC molecular data from U.S. minority residents is crucial to improve outcomes, as genomic phenotypes have been associated with differential prognosis and response to treatments. To our knowledge, minority patient-derived models have not been used to test GC therapies. In this study, several organoids lines from minority patients were established and used as an in vitro platform for screening effective therapies. After genomic data analyses, six minority patient-derived organoids with or without cell cycle regulator or PI3K/AKT/mTOR pathway gene alterations were tested for responses to first-line therapies, targeted drugs and combination treatments. Among the 24 PDX models established, the efficacy study of PDX model PDX015 which has amplifications of CDK and AKT genes showed the targeting therapy (a CDKi) can effectively prolong overall survival of mice bearing xenograft treated with the CDKi (60 days), compared with those mice in control group (22 days). In addition, an AKT inhibitor was found significantly inhibited tumor growth in CDKi-resistant mice treated with the CDKi/AKTi combination. In conclusion, investigating the efficacy of targeted therapies in these U.S. minorities will empower precision medicine applications in GC patients and improve GC treatment outcomes. Minority-patient derived tumor models have great potential in preclinical studies of chemotherapies and targeted therapies to address gastric cancer disparities.

Citation Format: Hongyong Zhang, Ana Patricia Estrada-Florez, Paul Lott, Ted William Toal, Alexa Morales-Arana, Alma Poceros-Coba, UCaMP Consortium, Ai-Hong Ma, Nicole Britney Halmai, Luis Carvajal-Carmona. Preclinical studies of chemotherapies and targeted therapies to address gastric cancer disparities [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3108.