PFN1 and breast cancer: Hypothesizing that Ser71 phosphorylation may be a pro-survival event by inhibiting the pro-apoptotic activity of Pfn1, we treated the stable MDA-MB-231 cells with paclitaxel, a commonly used chemotherapy agent which was reported to cause apoptosis in breast cancer cells more effectively upon Pfn1 overexpression (Zaidi et al., 2016).