In BMC Cancer this week, researchers in the US and Spain report their characterization of a novel PTEN mutation in a breast cancer cell line. The team evaluated PTEN expression in several human breast carcinoma cell lines and were able to generate a novel mutation in the PTEN gene in the MDA-MB-453 cell line. The mutation alters the gene's sub-cellular distribution and could lead to a predisposition of breast epithelial cells to transform into cancer cells, the authors write.