MKI67 and lymphoproliferative syndrome: By July 2013, a handful of key immunohistochemical (IHC) stains (Ki-67, p16, LANA, CD3, CD20, CD45, ER, and PR) were implemented primarily to support the KCH Lymphoma Study, an observational clinical cohort of lymphoproliferative disorders (LPDs) that continues to enroll to this day (3).