PTEN immunohistochemistry of an invasive adenocarcinoma [Inv.Aden.] and adjacent adenoma [Adenoma] which demonstrates altered PTEN expression. Both adenoma and adenocarcinoma are surrounded by lymphoid and stromal cells which are expressing PTEN. The normal stromal cells exhibit strong nuclear and cytoplasmic staining. The adenoma cells appear to have reduced nuclear but retained cytoplasmic staining, whereas the invasive cancer cells have lost both nuclear and cytoplasmic PTEN expression (×200).