Abstract C106: Enhanced characterization of molecular attributes through multi-omics analysis and comprehensive evaluation of global and local genomic ancestry in colorectal cancer among Hispanic-Latinos
Authors: Velazquez-Villarreal Enrique I. , Waldrup Brigette , Amzaleg Yonatan , Jin Yuxin , Postel Mackenzie , Loza Donna , Ovalle Serina , Quino Elizabeth , Chavez Carmen , Culver Julie , Stern Mariana C. , Lenz Heinz-Josef , Craig David W. , Carpten John D. 
Published: September 2024

Abstract
Introduction: Colorectal cancer (CRC) remains a significant public health challenge, representing the second leading cause of cancer-related mortality in the United States. Although mortality rates have generally decreased, the Hispanic/Latino (H/L) population in the Los Angeles area still experiences mortality rates up to 20% higher than those of their Caucasian American counterparts. Additionally, they are often diagnosed at a younger age and with more advanced disease stages, highlighting significant disparities in CRC outcomes. Currently, there are limited studies integrating clinical and multi-omics data from H/L populations, which are crucial for understanding the implications of colorectal tumorigenesis and addressing these disparities effectively. Methods: Clinical and genomic sequencing data were obtained from 60 primary CRC Tumor/Normal (T/N) samples within the Hispanic/Latino (H/L) population in the Los Angeles area through the PE-CGS network. For comparison, we analyzed 3,578 samples from non-Hispanic Whites (NHW) obtained from public databases. Additionally, we retrieved three CRC samples with spatial transcriptomic (ST) data from the 10xGenomics database. Using Whole Exome and RNA sequencing data, we performed somatic mutations, somatic copy number alterations (SCNAs), differential gene expression, cellular pathways, gene fusions, and global & local genomic ancestry analyses. The ST data underwent analysis utilizing newly released bioinformatics tools. Clinical and genomic data were integrated. Results: In these studies, distinct Amerindian (AMR) genomic ancestry proportion, age at diagnosis, and tumor localization patterns were observed, alongside significant mutations in key genes such as APC, TP53, and KRAS. The studies revealed evident cancer heterogeneity, influenced by factors such as mutation type, microsatellite instability, tumor subsite, and ethnicity. Additionally, several previously well-defined SCNAs were detected in the majority of tumors. Comparative analysis of gene expression and cellular pathways between H/L and NHW samples revealed distinct patterns. Furthermore, we identified gene fusions that potentially contribute to oncogenic activity in CRC. Ancestry analysis pointed to a predominant AMR ancestry. Notably, distinct associations of genetic ancestry with CRC tumor clinicopathological characteristics were identified. ST analysis delineated separate cancer, immune, and stroma components within the tumors. Conclusion: Our research has explored the molecular profiling of CRC tumors in H/L patients, providing crucial insights into the characterization of CRC tumors at the DNA and RNA levels, as well as the complex clinical and genomic diversity within our target population. Additionally, it offers valuable insights into the heterogeneity of CRC tumors and the tumor microenvironment. These findings establish the groundwork for subsequent projects, potentially leading to precision medicine approaches.
Citation Format: Enrique I. Velazquez-Villarreal, Brigette Waldrup, Yonatan Amzaleg, Yuxin Jin, Mackenzie Postel, Donna Loza, Serina Ovalle, Elizabeth Quino, Carmen Chavez, Julie Culver, Mariana C. Stern, Heinz-Josef Lenz, David W. Craig, John D. Carpten. Enhanced characterization of molecular attributes through multi-omics analysis and comprehensive evaluation of global and local genomic ancestry in colorectal cancer among Hispanic-Latinos [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr C106.