Characterization of DNA damage repair mutations in lung cancer in an underserved urban patient population.

e20058 Background: DNA-damage repair (DDR) mutations in lung cancer have shown potential for use as therapeutic targets and predictive biomarkers. However, the relationship between DDR mutations and socioeconomic factors remains largely unknown. In this study, we characterize the distribution of DDR gene mutations in lung cancer patients at a single academic medical center serving a unique population consisting of primarily underserved, underinsured patients. Methods: All lung cancer patients seen at the University of Illinois Chicago (UIC) between 11/2/2015 and 9/11/2023 with TEMPUS genetic data available were included in the study (N = 235). DDR mutations of interest were ARID1A, ATM, ATR, ATRX, BAP1, BRCA1, BRCA2, BRIP1, CHEK2, ERCC3, FANCA, FANCC, MLH3, MRE11, MSH6, MUTYH, NBN, PALB2, and RAD50. The population was subdivided into a DDR mutation positive group and a DDR mutation negative group. Each group was compared with respect to lung cancer type, tumor mutational burden (TMB), and socioeconomic factors including sex, race, insurance category, and zip code. Results: The overall frequency of DDR mutations in the population was 28.5% (n = 67). The most common DDR mutations were ARID1A (20.7%), CHEK2 (12.8%), ATM (9.9%), BRCA2 (9.9%), ATRX (7.9%), and MUTYH (7.9%). The histological distribution of the DDR mutation positive group was adenocarcinoma (76.1%), squamous cell carcinoma (4.4%), adenosquamous carcinoma (2.9%), neuroendocrine carcinoma (5.9%), and other (10.4%). The histological distribution of the DDR negative group was adenocarcinoma (60.1%), squamous cell carcinoma (22.0%), adenosquamous carcinoma (1.1%), neuroendocrine carcinoma (4.1%), and other (12.5%). There was a significant effect in TMB, t(55) = 2.97, p = 0.004, with a higher mean TMB in the DDR positive group (M = 14.4, SD = 11.1) compared to the DDR negative group (M = 9.4, SD = 5.1). The most common zip codes in the DDR positive groupwere 60608 (9.0%), 60629 (9.0%), and 60616 (7.5%) compared to 60616 (8.3%), 60609 (5.3%), and 60624 (4.7%) in the DDR negative group. Demographic factors of the two groups are compared below. Conclusions: The frequency and distribution of DDR mutations in lung cancer at UIC appears similar to what has been previously reported in the literature. There is a higher tumor mutational burden in lung cancers with DDR mutations, which may suggest greater susceptibility to immunotherapy. There may be a correlation between the presence of DDR mutations and lung cancer type, insurance category, and patient geographic distribution. Future work will include obtaining further geographic data for the study population such as average income, pollution exposure, and smoking rate by neighborhood. Table: see text