Abstract 5844: A comprehensive pan-cancer analysis of MDM2/MDM4 gene amplification in Chinese solid cancer patients

Abstract Background: Many patients with cancer have benefited from immunotherapy represented by the blockade of immune checkpoint PD-1/PD-L1. However, about 4-29% of cancer patients treated with immunotherapy developed hyper-progressive diseases(HPD) with accelerated tumor growth. MDM2/MDM4 amplification was suggested as genomic correlates for elevated risk hyperprogression. The objective of this study was to evaluate the frequency of amplification of MDM2/MDM4 in the Chinese solid tumor patients and to provide advice on the selecting of optimal treatment decisions. Methods: Tumor or blood samples were collected from 2,937 patients with solid cancer, genetic mutations and amplification was detected using the next-generation sequencing(NGS). Results: A total 112 patients with MDM2/MDM4 amplification were identified, including lung cancer 50.9% (57/112), colorectal cancer 14.3% (16/112), gastric cancer 8.0% (9/112), liver cancer 5.4% (6/112), Biliary tract cancers 4.5% (5/112), breast cancer 2.7% (3/112), and pancreatic ductal adenocarcinoma 2.7% (3/112). TMB value was identified, The median TMB for lung cancer was 9.13 mutations/Mb, median TMB for colorectal cancer was 13.8 mutations/Mb, a high TMB value in gastric cancer (median TMB=20.22 mutations/Mb), and median TMB for liver cancer was 17.9 mutations/Mb. Meanwhile, MSI was detected in 8% of patients with MDM2/MDM4 amplification, of which 3 in lung cancer, 5 in colorectal cancer, and 1in gastric cancer. Conclusions: Although amplification of MDM2/MDM4 was observed only in a small proportion of patients, it demonstrated an association with high TMB in several common cancer types. In addition, our data indicate that amplification of MDM2/MDM4 in different types of cancer is heterogeneous and that an appropriate immunotherapy strategy for patients with solid cancer should be noted. Citation Format: xiangyu sun, Zhichao Fu. A comprehensive pan-cancer analysis of MDM2/MDM4 gene amplification in Chinese solid cancer patients [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 5844.