Dissecting diffuse large B-cell lymphomas of the "not otherwise specified" type: the impact of molecular techniques.

The updated edition of the Classification of Tumours of Haematopoietic and Lymphoid Tissues, published in September 2017 by the World Health Organization (WHO), presents many important changes to the document published in 2008. Most of these novelties are linked to the exceptional development of biomolecular techniques during the last 10 years. To illustrate how much new technologies have contributed to the better classification of single entities, as well as the discovery of new ones, would go beyond the objectives of this work. For this reason, we will take diffuse large B-cell lymphoma as an example of the cognitive improvement produced by high-yield technologies (such as the gene expression profile, the study of copy number variation, and the definition of the mutational spectrum). The acquisition of this knowledge not only has a speculative value but also represents the elements for effective application in daily practice. On the one hand, it would allow the development of personalised therapy programs, and on the other it would promote the transition from the bench of the researcher's laboratory to the patient's bedside.

Reproducibility of SOX-11 detection in decalcified bone marrow tissue in mantle cell lymphoma patients.

Mantle cell lymphoma (MCL) usually harbors the t(11;14)(q13;q32) with overexpression of CCND1 mRNA and transcription of the cyclin D1 nuclear protein. Regardless of CCND1 status, most MCLs also express the SOX11 nuclear protein, which is thus helpful in the diagnosis of the rare CCND1-negative MCLs. Recently, SOX11 has been reported to be often negative in MCLs clinically resembling marginal zone lymphoma and recently defined as "leukemic non-nodal" MCL in the incoming revision of the WHO classification of lymphoid tumors, for which the bone marrow biopsy is commonly the first diagnostic approach. Due to the less aggressive clinical behavior of the latter MCLs, the reliable determination of the SOX11 antigen in decalcified tissue is mandatory. To this end, since little data are available in the literature, four commercially available anti-SOX11 antibodies (two polyclonal and two monoclonal) were tested on 21 positive staging bone marrow (BM) biopsies from cyclin D1/SOX11-positive MCL patients (17 fixed in B5, 4 in 10% buffered formalin) and on 9 positive BM biopsies from leukemic non-nodal MCL patients. The results were compared for specificity, sensitivity, staining strength and degree of an additional staining on myeloid precursors, also evaluating possible impact of the different fixatives used. Non-mantle cell lymphomas were also tested to address specificity. All reagents showed high sensitivity but the monoclonal code CMC38221001 provided the highest specificity and the lowest degree of non-lymphoid staining on myeloid cells. Formalin fixation generally improved the performance of most antibodies when compared to B5 fixation.

Intracellular TCR-signaling pathway: novel markers for lymphoma diagnosis and potential therapeutic targets.

Despite the immunologic functions of T-cell receptor signaling molecules being extensively investigated, their potential as immunohistochemical markers has been poorly explored. With this background, we evaluated the expression of 5 intracellular proteins-GADS, DOK2, SKAP55, ITK, and PKCα-involved in T-cell receptor signaling in normal and neoplastic hematologic tissue samples, using antibodies raised against fixation-resistant epitopes of the 5 molecules. All 5 antibodies were associated with normal T-cell differentiation. GADS, DOK2, SKAP55, and ITK turned out to be T-cell lineage-specific markers in the setting of lymphoid and myeloid precursor neoplasms but showed differential expression in peripheral T-cell lymphoma (PTCL) subtypes, being detected in PTCL/not otherwise specified (NOS) and angioimmunoblastic T-cell lymphoma but negative in anaplastic large cell lymphoma (ALCL). Peripheral B-cell lymphomas were consistently negative for ITK, with occasional cases showing expression of DOK2 and SKAP55, and a proportion (47%) of hairy cell leukemias were GADS. Notably, PKCα highlighted a defective antigen in both PTCL/NOS (6%) and angioimmunoblastic T-cell lymphoma (10%), mostly negative in ALCL, and was aberrantly expressed in classical Hodgkin lymphoma (65%), Burkitt lymphoma (48%), and plasma cell myeloma (48%). In conclusion, all five molecules evaluated play a role in T-cell differentiation in normal and neoplastic tissues. They can be applied confidently to routine sections contributing primarily to assignment of T-lineage differentiation in the setting of hematopoietic precursor neoplasms (GADS/DOK2/SKAP55/ITK) and for the differential diagnosis between ALCL and PTCL/NOS (GADS/DOK2/SKAP55/ITK) or classical Hodgkin lymphoma (PKCα). Finally, association with specific tumor subtypes may have therapeutic potential.