Proteomic analysis of anaplastic lymphoma cell lines: identification of potential tumour markers.

Anaplastic large-cell lymphomas (ALCL) are high grade lymphomas of T or null phenotype often associated with the t(2;5) translocation leading to the expression of a chimeric protein consisting of the N-terminal portion of nucleophosmin (NPM) and the intracellular domain of the anaplastic lymphoma kinase (ALK). Although ALCL are recognized as distinct clinical, biological and cytogenetic entities, heterogeneities persist in this group of tumours, which exhibit a broad spectrum of morphological features. Particularly, the common type tumour consisting in large cells contrast with the small cell variant that is sometimes associated with a leukemic phase. The ALK-negative ALCL is often associated with a poor prognosis. Here, we investigated the proteome of these subtypes of tumours using patient-derived cell lines. We compared the proteome of the cytosolic fraction of NPM-ALK-positive versus NPM-ALK-negative cells on one hand, and the proteome of common cell type versus small cell variant on the other hand. The identification of a set of proteins differentially expressed in the subtypes of ALCL points to new diagnosis/prognosis markers. This study also provides interesting information on the molecular mechanisms responsible for the different subtypes of ALCL.