Triple negative breast cancer (TNBC) is an aggressive form of breast cancer that often strikes young women, particularly minority women in their reproductive years. This cancer is very aggressive and has a poor prognosis mainly, due to the lack of effective chemotherapeutic agents. Recently, molecular profiling of a patients’ tumors yielded detection of specific driver genes in primary tumors that resulted in the use of a single or combination therapies targeting those driver genes. Triple negative breast cancers present an additional problem, in that they are found in different forms or subtypes histologically and molecularly. Basal 2 subtype is one of the most aggressive form of TNBC. Studies have shown that histologically designated tumors yield different treatment results. This study examined the molecular profiles of two Basal 2 triple negative breast cancers representing two different African American women and their response to vorinostat. Using a RT2 Profiler PCR gene expression array, vorinostat was found to up-regulate 54 genes and downregulated 3 genes in HCC70 TNBC. In HCC1806, 23 genes were upregulated and 38 downregulated. The most significant changes in gene expression were noted in CCND2 expression.

Changes were also noted in SNA12, SERPINE, SLC39A6, AR, BRAC1 and TWIST. In HCC1806, significant changes in gene expression were noted in ABCB1, CCND2, CDKN1C and MMP9. Up-regulation of CCND2 was observed in both basal 2 cell lines. CCND2 encodes cyclin D2 in which low expression is associated with poor prognosis. Understanding individual differences in cancer driver genes will greatly improved personalized medicine in triple negative breast cancer.

Citation Format: Beverly Word, Ebony Cotton, George Hammons, Beverly Lyn-Cook, Density Stovall. Molecular profiling of basal 2 subtypes of triple negative breast cancer cells and their response to a histone deacetylase inhibitor [abstract]. In: Proceedings of the AACR Virtual Conference: Thirteenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2020 Oct 2-4. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(12 Suppl):Abstract nr PO-218.