Proteomic Profiling of Lymph Nodes Differentiates Classic Hodgkin Lymphoma With and Without Skeletal Involvement

Classic Hodgkin lymphoma (CHL) is a highly curable disease, even in advanced stages. Controversy remains over whether bone involvement negatively affects overall and progression-free survival in patients treated with intensive chemotherapy regimens. Whether cases that present with bone lesions harbor specific tumor microenvironmental features is unknown. We investigated protein expression in diagnostic lymph node biopsies from CHL patients with and without skeletal involvement at diagnosis to identify potential markers of skeletal disease. Protein expression patterns in diagnostic formalin-fixed paraffin-embedded lymphoma lymph node samples from CHL patients were analyzed by nano-liquid chromatography-tandem mass spectrometry. Patients were grouped according to skeletal involvement, which was defined as the presence of one or more FDG-avid lesions on a diagnostic FDG-PET/CT scan. Protein profiles identified patients with skeletal disease at diagnosis and showed disrupted cellular pathways, including immune system processes, cell adhesion, and cell growth/survival. Immunohistochemical evaluation also demonstrated differential expressions of angiotensin-converting enzyme (ACE), intercellular adhesion molecule 3 (ICAM3), integrin alpha-X (ITGAX), and calreticulin (CALR). In conclusion, proteomics identified altered protein expression profiles in lymph nodes among CHL cases presenting with disease disseminated to the skeletal system, which implies altered disease pathogenesis for these patients.