Evidence-based cancer diagnostics — classification, biomarkers, and molecular testing.
A patient with newly diagnosed triple-negative breast cancer, aged forty-two, asks whether her diagnosis was inherited — and whether it changes her treatment. That single question now sits at the intersection of oncology, surgery, genetic counseling, and pathology, and the germline BRCA1/BRCA2 test is what begins to answer it. What was once framed almost entirely as a question of familial cancer risk has, over the past several years, become a predictive biomarker: a result that helps determine which classes of drug a patient may be eligible for. That dual role…
More in Breast →HER2, encoded by the ERBB2 gene, is a receptor tyrosine kinase in the epidermal growth factor…
More in Colon →For decades, the Ki-67 proliferation index has occupied an awkward middle ground in diagnostic pathology: a…
More in Digital Pulse →Most estrogen receptor–positive, HER2-negative (ER+/HER2−) breast cancers respond well, at first, to endocrine therapy. The problem is durability. Under the sustained selective pressure of an aromatase inhibitor, subclones carrying mutations in the estrogen receptor gene, ESR1, can expand. These mutations — clustered in the ligand-binding domain — lock the receptor into a constitutively active, estrogen-independent…
More in Liquid Pulse →MET is a receptor tyrosine kinase encoded by the MET gene, and its ligand, hepatocyte growth factor, drives signaling that governs cell proliferation, survival, and motility. In a subset of non–small cell lung cancers (NSCLC), that pathway becomes a dependency. But there are several biologically distinct ways this happens, and pathologists need to keep them…
More in Lung →The advent of CD19-directed cellular and antibody therapies has transformed the management landscape for relapsed or refractory aggressive B-cell lymphomas. With this transformation comes a new diagnostic responsibility: documenting whether the therapeutic target—CD19—is actually present on a patient's tumor. This article reviews CD19 as a predictive biomarker, explaining what its assessment measures, how it is tested, and how the results inform eligibility for a class of targeted therapies. Throughout, the goal is educational clarity for a mixed audience of pathologists, oncologists, trainees, and informed patients. CD19 is a transmembrane glycoprotein…
More in Lymphoma →A 48-year-old woman presents with a pelvic mass and ascites. The biopsy shows clear cytoplasm, tubulo-cystic…
More in Ovarian →Among the most frequently deployed tools in surgical pathology of the prostate is a compact panel…
More in Prostate →