(A) AN INTRODUCTORY SENTENCE INDICATING THE PURPOSES OF THE STUDY:    Ovarian cancer (OC) is a heterogeneous disease with high grade serous ovarian cancer (HGSOC) as the commonest, the most aggressive tumor, which is often diagnosed at advanced stages, and with poor overall survival. Unfortunately, like many other cancer diagnoses, women of West African ancestry (Black women) with ovarian cancer experience worse outcomes than White women. In the US, Black women have higher morbidity and mortality rates and higher un-staged or unclassified tumors compared with White women, resulting in undertreatment with subsequent compromise in progression-free survival. Genomic instability is one of the most common underlying features of ovarian cancer and defective DNA damage repair has been implicated. The goal is to uncover canonical genes associated with the aggressive behavior of HGSOC in a cohort of black women that could explain the biology of this tumor. (B) A BRIEF DESCRIPTION OF PERTINENT EXPERIMENTAL PROCEDURES:   Formalin fixed paraffin embedded (FFPE) HGSOC tissue blocks from Nigeria in West Africa (WAB), Bahama in Caribbean (CBB), and Miami in USA (USB) were identified and selected after rigorous review and confirmation with immunohistochemical (IHC) markers when needed. Integration of digital histopathology and IHC markers (estrogen receptor, progesterone receptor, Ki67 and P53), whole exome sequence, RNA sequence of the FFPE samples was used to identify the proportion of genomic instability and defective DNA damage repair genes. We use spatial genomic library on tissue microarray (TMA) slide prepared on GeoMx digital spatial profiler (DSP) Nanostring platform to study the biology of the tumor and the tumor microenvironment (TME) and proteogenomics.(C) A SUMMARY OF THE NEW, UNPUBLISHED DATA:   The unsupervised principal component analysis of the tumor showed a distinct population of WAB and USB while the CBB showed admixture population. BACH2, ARG1, NAFT2 and FRA10A1 are commonly differentially expressed genes among the cohort. There is low expression of routine IHC markers among the WAB compared to the other groups.     Conclusion:   There is variation on gene expression by nativity and we hope to explore this variation for therapeutic purpose among black women with ovarian cancer.  

Citation Format: Ayodele Omotoso, Uchenna Ezenkwa, Raleigh Butler, Melissa Castillo, Alex Sanchez-Covarrubias, Matthew Schlumbrecht, Andre Pinto, Bala Audu, Sophia George. Genetic profiling of high grade serous ovarian cancer among women of African ancestry [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr C092.