title: Immunohistochemical markers in lymphoid malignancies: Protein correlates of molecular alterations.
abstract: Histomorphology, immunohistochemistry (IHC), and genetics are essential tools for the evaluation and classification of lymphoid malignancies. Advances in diagnostic techniques include the development of immunohistochemical assays that can serve as surrogates for genetic tests. We review the performance of a select subset of assays that detect the aberrant expression of onco-proteins secondary to chromosomal translocations (MYC; BCL2), somatic mutations (BRAF V600E; NOTCH1), and gene copy number gains (CD274 (encoding PD-L1); PDCD1LG2 (encoding PD-L2)) in fixed tissue biopsy sections. We discuss the limitations of IHC, but also its primary advantage over genetics; specifically, its ability to assess the final, common phenotypic consequences of a multitude of genetic and non-genetic events that influence protein expression. The information provided by IHC and genetic testing are thus intimately related; surgical pathologists will increasingly need to interpret and integrate the results of both to provide a comprehensive assessment of tumor biology and guide therapy.
authors.affiliation: Department of Pathology, Brigham and Women 's Hospital, Boston, Massachusetts.
authors.forename: Caleb
authors.initials: C
authors.lastname: Ho
authors.affiliation: Department of Pathology, Brigham and Women 's Hospital, Boston, Massachusetts. Electronic address: srodig@partners.org.
authors.forename: Scott J
authors.initials: SJ
authors.lastname: Rodig
mesh_terms: D014408:Biomarkers, Tumor / Q000235:genetics*; D019337:Hematologic Neoplasms / Q000737:chemistry / Q000235:genetics* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008221:Lymphoid Tissue / Q000737:chemistry* / Q000473:pathology; D025202:Molecular Diagnostic Techniques; D009154:Mutation; D009363:Neoplasm Proteins / Q000235:genetics*; D011237:Predictive Value of Tests; D011379:Prognosis; D015203:Reproducibility of Results
chemical_list: D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins
keywords: Genetic alteration; Hematologic malignancy; Immunohistochemistry; Protein expression