Metallothionein as a useful marker in Hodgkin lymphoma subclassification

Metallothionein (MT) expression is considered to be a prognostic factor that promotes tumor resistance to apoptosis. In non-Hodgkin lymphomas, MT is differentially expressed and constitutes a risk factor. We have characterised MT in lymph nodes of Hodgkin lymphoma (HL) [patients with nodular sclerosis (NSHL), mixed cellularity (MCHL), lymphocyte-rich classical HL (LRCHL) and nodular lymphocyte predominant HL (NLPHL)] and in controls. MT expression is significantly and differentially altered in the HL subtypes. NSHL and MCHL show highly increased MT throughout the lymph node. In contrast, MT is barely increased in LRCHL relative to controls. NLPHL shows a distinct pattern of heterogeneous MT with increased MT in nodular areas surrounded by MT-negative tissue. The cellular MT sources are reactive, infiltrating (non-neoplastic) cells, whereas neoplastic cells are devoid of MT. We show for the first time that MT is differentially expressed in subclassified HL.