To test the hypothesis that OCT-1 may be an important therapeutic target in breast cancer, we analyzed cell migration, growth rate, response to endoplasmic reticulum stress, and cell survival under hypoxia conditions following a reduction in the total OCT-1 or OCT-1A isoform expression levels in a triple-negative breast cancer cell line (MDA-MB231). This evidence concerns the gene POU2F1 and breast cancer.