RNA-binding proteins (RBPs) play central roles in regulating posttranscriptional gene expression, and their abnormal expression or function amplify the effects of cancer-driver genes, accelerates tumor progression and promote aggressiveness. TDP-43 is a RBP that, amongst other functions, participates in mRNA metabolism. It is a key player in neurodegenerative diseases like frontotemporal dementia and amyotrophic lateral sclerosis. Although recent evidence suggests a potential role in other pathogenic processes, the involvement of this protein in cancer is still unclear. In this work, we aimed to i) investigate the differential expression of TDP-43 in different cancer types, and ii) analyze the levels and localization of TDP-43 in breast cancer (BC) cell lines in vitro (MCF7, MDA-MB-231) using different TDP-43 antibodies. For the first purpose, we interrogated the CPTAC public dataset (breast, glioblastoma, colon and lung) using cBioportal to characterize mutations in the TARDBP gene and stratify samples according to the 25% and 75% quartiles of TDP-43 expression to identify the overrepresented biological pathways. Interestingly, RBPs and RNA metabolism were the top pathways present in the 75% quartile. Secondly, we used different antibodies raised against the N-terminal (N-t), C-t or internal regions of TDP-43, to investigate the localization of TDP-43 in cultured BC cell lines. Remarkably, although most cells studied so far (in culture, or in rodent and human tissue) had a predominantly nuclear TDP-43 localization, we show evidence of abundant cytoplasmic expression in BC cell lines under basal culture conditions. Moreover, since TDP-43 cytoplasmic mislocalization and aggregation are considered as pathological features in human neurological diseases, we are expanding our analysis to determine TDP-43 levels, localization and aggregation in BC samples. In summary, we provide evidence for a potential role of TDP-43 in BC that deserves further investigation.