Abstract 5094: A pan-cancer analysis of GRIN2A as a potential biomarker for immune checkpoint therapy

Abstract Background: GRIN2A is the encoding gene of GluN2A, which is a subunit of the N-methyl-D-aspartate receptor, and participates in the regulation of excitatory neurotransmission in the brain. GRIN2A is one of the key genes in epilepsy researches, however, only a few researches have been done on GRIN2A in cancer field. The existing studies showed that GRIN2A mutation was frequently found in melanoma and caused abnormal tumor suppressor function. Besides, GRIN2A mutation was associated with higher tumor mutation burden (TMB) in non-small-cell lung cancer, suggesting that GRIN2A-altered tumors might be more sensitive to immune checkpoint inhibitors (ICIs), but the correlation of GRIN2A mutation status with immune response in clinical remains unknown. Methods: Next generation sequencing (NGS) and clinical data of pan-cancer patients were obtained from two MSK-IMPACT Clinical Sequencing cohorts (MSK-2017, N=10336; MSK-2019, N=1661). The MSK-2019 cohort, which was treated with ICIs, were analyzed to explore the association between GRIN2A alteration and therapeutic efficacy of ICIs. Moreover, mRNA expression data of 10201 pan-cancer patients were obtained from the Cancer Genome Atlas (TCGA) database to explore the association between GRIN2A expression level and immune cell infiltration. Results: In total, 3.74% (387/10336) of pan-cancer patients in MSK-2017, and 7.47% (124/1661) in MSK-2019, carried GRIN2A alteration. In MSK-2017, the top three GRIN2A alteration frequency cancer types were melanoma (68/365, 18.63%), skin cancer (non-melanoma, 22/148, 14.86%) and small cell lung cancer (11/82, 13.41%), respectively. And the commonly mutation types of GRIN2A were missense mutation. In MSK-2019 treated with ICIs, the TMB level of GRIN2A-altered group was significantly higher than wild group (median TMB, altered-type vs. wild-type = 25.09 vs. 5.90 Muts/Mb, P<0.0001) and the overall survival (OS) of GRIN2A-altered group were significantly longer than wild group (OS, median, 44.00 vs. 15.00 months; HR=0.5812 [95%CI: 0,4474-0.7550], P=0.0008). But in MSK-2017 without immunotherapy, there was no difference in OS between GRIN2A-altered group and wild group (OS, median, 26.00 vs. 26.13 months; HR=1.194 [95%CI: 0.9588-1.487], P=0.0849). Furthermore, the GRIN2A expression level was positively correlated with the degree of immune cell infiltration in some tumor types, such as prostate adenocarcinoma (PRAD), while some tumors did the opposite, such as sarcoma (SARC). Conclusion: The results indicated that GRIN2A gene alteration was associated with a higher TMB level in pan-cancer patients, and patients carrying GRIN2A alteration might easily benefit from ICIs. Citation Format: Mei Jiang, Xuefeng Zhong, Mengli Huang. A pan-cancer analysis of GRIN2A as a potential biomarker for immune checkpoint therapy [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 5094.