Nearly 70% of human genes undergo Alternative Polyadenylation (APA) due to the presence of alternative adenylation sites in the genome that alters the architecture of mRNA 3’-UnTranslated Regions (UTRs) leading to significant transcriptome diversity. Thus, a same gene can give rise to mRNA isoforms with same protein coding potential but variable 3’UTR length and regulatory content. Several APA genes switch to shorter mRNA isoforms in cancer cells and have been proposed to have prognostic potential. Our study aims to detect signatures of 3’UTR switching that are specific to triple negative breast cancer (TNBC). Combined with the reported APA markers, we use data from four triple-negative breast cancer patients sequenced using 10X single-cell technology to understand the behaviour of these APA markers at cellular level. We will present our current work to answer if these 3’UTR signatures can be used to identify tumour cells at single-cell resolution.