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). This evidence concerns the gene PTPRC and lymphoproliferative syndrome.