Abstract 1255: Identification of predictive biomarkers for neoadjuvant chemotherapy response in invasive breast cancer Latino patients

• Published in: Cancer research (Chicago, Ill.) Ill.), 2022-06, Vol.82 (12_Supplement), p.1255-1255
• Main Authors: Guevara-Nieto, Hedda Michelle, Parra-Medina, Rafael, Mejia-Henao, Juan Carlos, López-Correa, Patricia Eugenia, Guío-Avila, José Ismael, Diaz-Casas, Sandra, Garai, Jone, Zabaleta, Jovanny, López-Kleine, Liliana, Cómbita, Alba Lucia
• Format: Article
• Language: English
• ISSN: 1538-7445; 1538-7445
• DOI: 10.1158/1538-7445.AM2022-1255

Purpose: Breast cancer (BC) is the leading cause of morbidity and mortality in women in Colombia, constituting a major public health issue. Importantly, not all breast cancer patients respond to neoadjuvant chemotherapy (NAC), leading to an incomplete pathological response and suggesting that there are tumor characteristics that may explain the differences in response. The overarching goal of this study is to identify gene expression profiles associated with an incomplete pathological response to NAC in Colombian women with invasive BC. Design: An integrative transcriptome analysis using Illumina high-throughput RNA sequencing was performed from 63 baseline and post-NAC (follow-up) paraffin-embedded samples from 46 different female patients with locally advanced BC (stage IIB to IIIC) treated at the Colombian National Cancer Institute. Gene expression data were obtained from 42 baseline and 21 follow-up samples. Two comparison analyses were conducted to identify differentially expressed genes (DEGs) first comparing baseline vs follow-up samples from nonresponders to NAC and second comparing to baseline samples from nonresponders vs responders to NAC. Additionally, enrichment analyses were performed in both comparative analyses. Results: From 46 patients included, 20 had a pathological complete response (pCR), while 26 did not show pCR. By investigating the gene expression profiling, 1546 significantly DEGs and 174 DEGs were identified among non-responders and Baseline analyses, respectively. From these analyses, 24 DEGs were found in common and apoptosis as the only shared enrichment pathway (p=0.001). In both analyses, Histone associated genes were downregulated in nonresponders (Histone 3, p=0,001 and Histone 2B, p